Koofers

exam 1 - Flashcards

Flashcard Deck Information

Class:BIOL 2020 - Human Anatomy and Physiology II
Subject:Biology (MTSU and RODP)
University:Middle Tennessee State University
Term:Spring Term 2013
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100,000 beats per day The heart never rests, so how many times does it beat per day?
blood vessels

can be divided into:

  1. pulmonary circuit
  2. systemic circuit
pulmonary circuit carries blood to and from the lungs
systemic curcuit transports blood to and from the rest of the body
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oxygen-rich The right side of the pulmonary circuit carries more _________ blood because it is coming straight from the lungs.
curcuits operate simultaneously
25 days the heart starts beating ~____ days post-conception
arteries

carry blood away from the heart

*even if unoxygenated

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pulmonary _________ arteries carry oxygen poor blood to the lungs
capillaries thin-walled, microscopic vessels that connect the smallest arteries to the smallest veins
capillaries gases, nutrients, and wastes are exchanged with the tissues through the very thin walls of the _________
pulmonary _________ veins are very richly oxygenated
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right atrium receives O2-poor blood from the body and passes it to the right ventricle
Right ventricle pumps blood to the lungs
left atrium receives oxygen-rich blood from pulmonary circuit and passes it to the left ventricle
left ventricle pumps blood into systemic ciruit
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heart attack caused by a lack of oxygen and blood flow to the heart
chest pain (angina) caused by short term blockage of blood flow to the heart
heart murmur caused by leaking regurgitation of heart valves
nitrogliserin drug that causes chest to open up and help angina
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cardiac arrhythmia when your heart is not beating in proper rhythm and uses a defibrilator
heart directly posterior to the sternum; roughly from the 3rd costal cartilage to the end of the body of sternum
anterior mediastinum where the heart lies; space between 2 lungs
thymus the endocrine structure in the anterior mediastinum and is the gland deepest to sternum
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base the _______ of the heart refers to the attached superior end
apex the heart is tilted such that the ______ is about 3 inches left of the midline of the body
right the heart is also rotated such that in an anterior view of the body, we see mainly the _______ atrium and _______ ventricle
pericardium

the fibrous sac that surrounds the heart; consists of two layers:

  1. parietal paricardium
  2. visceral paricardium (aka epicadium)
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parietal pericardium the outer layer of the pericardium that consists of dense irregular and areolar CT with an inner lining of simple squamos EPI
dense irregular type of connective tissue in the parietal pericardium that resists stretching
simple squamous EPI type of EPI that makes up the inner lining of the parietal pericardium that reduces friction
visceral pericardium (aka epicardium) the inner layer of the pericardium that clings to the heart
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histamine the release of this causes inflammation (swelling)
pericardial cavity the potential space between the parietal and visceral layers and contains pericardial fluid
pericardial fluid lubricating fluid in the pericardial cavity that reduces friction between the beating heart and the surrounding tissues
pericarditis inflammation on the pericardium and increases friction, e.g. due to infection of trauma
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pericarditis when this is present, doctors can actually hear a scratching noise with a stethoscope
epicardium outermost layer of the heart wall (same as the visceral pericardium) that consists of an outer layer of simple squamous EPI over an inner layer of areolar CT that clings to the myocardium
myocardium the muscular wall of the heart that forms both the atria and ventricles
nerves controls power of contraction in tissue
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myocardium layer of the heart wall that is composed of cardiac muscle tissue, blood vessels, and nerves
myocardium layer of the heart that consists of concentric (nesting) layers of muscle tissue
endocardium the innermost layer of the heart wall
endocardium a simple squamous EPI that is continuous with the inner lining of the large blood vessels that attach to the heart and has very little turbulence
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cadiac muscle like skeletal muscle, it is striated and made up of myofibrils (with sacromeres)
sacromeres made up of Z-discs
cardiac muscles unlike skeletal muscles, they are quite small and usually uninucleate
skeletal muscle incredibly long compared to cardiac muscle, 5-10 times bigger. cells fuse together early, causing this muscle to be multinucleated.
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mitochondria

uses oxygen to generate ATP

slow ______-twitch muscle is created for long-term use
cardiac muscle cells these cells have more mitochondria and the mitochondira are HUGE (make up ~25% of cell volume), have lots of myoglobin, and are even more richly vascularized than average skeletal muscle
myoglobin stores oxygen in cardiac muscle cells
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cardiac muscle cells wider, but shorter T-tubules and less sarcoplasmic reticulum than skeletal muscle
calcium in skeletal muscle, the trigger for contraction is the release of _______ from the sarcoplasmic reticulum
T-tubules in cardiac muscles, the trigger of contraction also involves the influx of calcium into the cell through these larger ________
T-tubules allow change in electrical charge and calcium is released from the sarcoplasmic reticulum
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cardiocytes are typically branched
intercalated discs cardioctyes are connected to several other cardiocytes at special sites called:
interdigitating folds the bumpy surface at the ends of the cells that increase the surface area for cell-cell connections
plasma the _______ membranes of adjacent cells are joined by desmosomes and gap junctions
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desmosomes resist stretching and help transfer the force of contraction from cell to cell
gap junctions allow small molecules and ions to flow between the cells thereby electrically connecting the cells
action potentials ___________ can quickly travel from cell to cell through the gap junctions
gap junctions in a sense, they allow the cardiocytes of the two atria to act like a single, huge cell
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autorhythmic the tissue contracts without neural stimulation 
pacemaker cell the timing of contractions is controlled by this special type of muscle cell 
contraction motor neurons can influence the pacemaker and the force of ________
cardiac muscle tissue tissue that is totally dependent on aerobic metabolism (respiration)
-hence lots of large mitochondria and myoglobin
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fatigue cardiac muscle does not readily ________
twitches ________ do not sum up in cardiac muscle as in skeletal muscle; therefore, the heart cannot produce a sustained contraction 
cardiac muscle tissue this type of muscle tissue is beneficial because if the heart became locked in a sustained contraction, it couldn't pump blood. 
-slow twitch=high stamina
Right atrium the path of blood through the heart starts here; it receives blood from the systemic circuit through the two great veins: superior & inferior vena cava 
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superior vena cava great vein that connects to the superior right atrium and carries deoxygenated blood from the upper body 
inferior vena cava great vein that connects to the inferior right atrium and carries deoxygenated blood from the lower body
auricle when not filled with blood, the outer portion of each atrium (both right and left) deflates into a wrinkly flap called the ________ ("ear")
interatrial septum the relatively thin wall separating the right and left atria
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foramen ovale from early embryonic development until birth, there's an oval opening, called the _____________, through the interatrial septum that connects the right and left atria
foramen ovale this was beneficial before birth because it bypasses lungs
fossa ovalis after closing, the foramen ovale becomes the ___________, a small, shallow depression that persists into adulthood 
Right ventricle blood flows from the right atrium through the right atrioventricular (AV) valve into the ___________
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cusps fibrous flaps 
right atrioventricular (AV) valve aka Tricuspid valve; has three cusps that are connected to chordae tendinae originating at the papillary muscles
chordae tendinae the free edge of each cusp is attached to connective tissue fibers called the __________ that originate at the papillary muscles and stabilize valves
papillary muscles where the chordinae tendinae originate; are conical muscular projections from the inner surface of the right ventricle 
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contracts when the right ventricle __________, the right AV valve closes and prevents the backflow of blood into the right atrium
chordae tendinae prevents overextension of the cusps 
(e.g. prevent them from acting like swinging doors)
trabeculae carneae the inner surface of the ventricle has a series of muscular ridges called the:
pulmonary circuit when the right ventricle contracts, it pumps blood through the pulmonary semilunar valve to enter the pulmonary trunk, which starts the _____________
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pulmonary semilunar valve these valves are called "semilunar" because the cusps have a half-moon shape and they prevent backflow of blood into the right ventricle upon relaxation of the ventricle 
pulmonary arteries During the pulmonary circuit, the pulmonary trunk quickly divided into the right and left ____________
pulmonary arteries these arteries divide into smaller and smaller branches until they deliver blood to the delicate gas-exchange sites of the lungs
pulmonary veins during the pulmonary circuit, after the exchange of gases in the lungs, oxygenated blood flow into the right and left ______________
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left atrium the right and left pulmonary veins deliver blood to the:
left ventricle blood flows from the left atrium through the left atrioventricular (AV) valve into the:
interventricular septum a thick wall separating the right and left ventricles 
left atrioventricular (AV) valve aka Bicuspid or Mitral valve; has only two cusps and also works via chordae tendinae and papillary muscles 
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left atrium when the left ventricle contracts, the left AV valve closes and prevents the backflow of blood into the:
ascending aorta blood is pumped by the strong left ventricle through the aortic semilunar valve into the: 
left ventricle the right and left ventricles hold equal amounts of blood, but the ______ ventricle has much thicker walls, making it more muscular
adema when you have unequal blood flow, you have swelling (________) that could create blockage and ruin pump.
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pressure the thicker, stronger walls enable the left ventricle to pump with much greater _______ than the right ventricle
right ventricle this ventricle only has to pump blood at low pressure a short distance (~6 inches)
left ventricle this ventricle has to pump blood throughout the systemic circuit and requires as much as 5x as much as the other ventricle
interventricular septum when the right ventricle contracts, it acts like a "bellows" and squeezes blood against the thick ____________
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contractions happen simultaneously 
right ventricle this ventricle has a pouch-like shape
left when the powerful _______ ventricle contracts, all of its walls contract such that the ventricle both shortens in length (from apex to base) and decreases in diameter
left ventricle this ventricle is round in cross-section 
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contracts when the left ventricle ________, it bulges into the right ventricular cavity and helps the right ventricle do its job 
heart beat this is created when the atria contract simultaneously and then the ventricles contract simultaneously sending equal volumes of blood to pulmonary and systemic circuits
valves heart _______ permit blood to flow in one direction only
atrioventricular valves valves that prevent blood from being forced backed into atria when ventricles contract, and without them, pumping efficiency would be very poor  
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ventricles with the _______ contract. blood moving back toward the atria swings the cusps of the valves together, sealing the valve 
chordae tendinae a split second before the ventricles contract, the papillary muscles contract and tighten the __________ thereby preventing the cusps from swinging into the atria 
papillary muscle if these were damaged, each time ventricles contract, there would be backflow (regurgitation) into the atria 
semilunar valves valves that prevent the blood from leaking back into the ventricles when the ventricles are relaxed 
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semilunar valves unlike the AV valves, these valves neither have nor need muscular braces because the pressure they need to withstand is much less (after all, the ventricles are relaxed)  
semilunar valve each has three cusps that brace each other in the closed position 
valvular heart disease (VHD) occurs if the valves malfunction to the extent that the heart cannot pump efficiently 
carditis sometimes valves are faulty at birth, but often faulty valves develop after ________ (inflammation of the heart) occurs 
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cardiac skeleton aka fibrous skeleton; consists of four dense bands of tissue that encircle the heart valves as well as the bases of the aorta and pulmonary trunk
bands the _______ of the cardiac skeleton stabilize the heart valves and the bases of the great vessels 
cardiac skeleton electrically insulate the cardiac cells of the ventricles from those of the atria and helps not to pump out of rhythm 
heart lots of collagen and elastic fibers support the structure of the ______
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cardiac muscle cell each of these muscle cells are wrapped in a strong, but elastic, sheath 
cross-links what neighboring cells are "tied" together by in the connective tissue of the heart 
connective tissues
  • physically supports the muscle cells, nerve cells, and blood vessels of the heart 
  • prevent overexpansion of the heart 
  • help heart "spring" back into its original size after contracting
  • help distribute the force of contraction
connective tissue helps distribute the force of contraction so that one area doesn't suffer most of the wear and tear 
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heart weighs less than 1% of your total body weight and gets 5% of your total blood 
heart since this organ is constantly active, its muscle cells need lots of oxygen and nutrients therefore it needs to send itself a large amount of blood 
coronary circulation the blood supply to the heart is called the:
coronary the _______ arteries (right and left) emerge from the base of the aorta
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coronary arteries these arteries emerge very close to the aortic semilunar valve 
relaxation blood only enters coronary arteries during _________
coronary when the left ventricle contracts, it forces blood into the aorta, but little blood flows into the ________ arteries, because the cusps of the valves block them
recoil when the ventricle relaxes, the stretched walls of the aorta relax and _______: (aka elastic rebound) both pushes blood further into the systemic circuit and into to coronary arteries 
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coronary arteries are among the most variable aspects of all human anatomy
right coronary artery supplies blood to the right atrium and the right ventricle 
Posterior interventricular branch branch of the RCA that supplies blood to both posterior ventricles
left coronary artery runs along margin of the left atrium; quickly splits into two major branches:
  1. circumflex branch 
  2. anterior interventricular (descending) branch
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circumflex branch branch of the LCA that supplies blood to the left atrium and posterior ventricle 
anterior interventricular (descending) branch branch of the LCA that supplies blood to both ventricles
anastomosis the anterior interventricular branch of the LCA eventually joins to the posterior interventricular branch of the LCA; such a convergence is called an __________
anastomosis this is helpful because it gives you an alternate blood flow route
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great cardiac vein vein that drains blood from the anterior heart and runs alongside the anterior interventricular branch of the LCA
Middle cardiac vein aka posterior interventricular vein; drains blood from the posterior heart and runs alongside the posterior interventricular branch of the RCA 
Small cardiac vein vein that drains blood from posterior right atrium and runs alongside the RCA and posterior right atrium 
coronary sinus all the cardiac veins empty into this which, in turn, empties into the right atrium and has a large, thin-walled vein on the posterior of the heart
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heart attacks (myocardial infarctions, MI) account for ~50% of all deaths in the US
heart attacks caused by a long-term insufficient supply of blood to one or more parts of the heart muscle that suddenly kills a patch of the myocardium 
infarctions death of tissue due to a stoppage of blood flow
coronary arteries the poor blood supply is usually due to a blood clot or atherosclerosis of the ____________ 
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heart attack patients may recover from this if the damage to the heart is small enough such that the heart can still pump efficiently, but typically the MI weakens the muscle and/or disrupts the conduction of electrical signals
atherosclorosis accumulation of fatty tissue that blocks the artery 
angina pectoris "chest pain" : a sense of heaviness or pain in the chest and often the left arm and shoulder and is caused by a SHORT TERM slow down or blockage of blood flow 
-e.g. a partially blocked coronary artery constricts temporarily 
angina pectoris during _________, when the artery dilates, or relaxes, the artery releases and goes back to normal 
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anaerobic fermentation with insufficient blood and oxygen, the cardiocytes switch to ____________ during angina pectoris 
chest pain the warning sign that the blood supply is weak to the heart  
resumes the chest pain during angina pectoris will abate when blood flow _______
conducting system a network of specialized cardiac muscle cells that initiates and distributes the electrical impulses through the heart that stimulate the heart to contract 
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cardiac since it has its own conducting system, _______ muscle contracts on its own and does not require neural stimulation; it's autorhythmic (unlike skeletal muscle) 
cardiac muscle cells two types of these cells are involved in a normal heartbeat:
a. contractile cells
b.  conducting cells
contractile cells the muscle cells that actually contract and propel the blood 
-e.g. actin and myosin
conducting cells specialized muscle cells which coordinate the contraction
-i.e. they make sure the contractile cells push blood in the correct direction and at the correct time 
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conducting cells typically smaller than the contractile cells and have few myofibrils
contraction in cardiac muscle, the actual _________ lags behind the electrical stimulation (similar to skeletal muscle)   
calcium, troponin because the electrical impulse has to spread throughout the cardiocyte, _______ has to be released from the sarcoplasmic reticulum and bind to _______, which finally uncover the binding sites etc.
binding sites where strands of myosin bind to actin receptors 
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components of the conducting system
  1. Sinoatrial (SA) node
  2. Internodal pathways
  3. Atrioventricular (AV) node
  4. AV bundle (Bundle of His)
  5. Bundle Branches
  6. Purkinje fibers 
prepotentials the conducting cells of both nodes (SA and AV) exhibit _______
prepotentials aka pacemaker potential; a gradual depolarization; in other words, the cell membranes of these conducting cells cannot maintain a stable resting potential  
positive the potential of both nodes (SA and AV) drift more _______ toward threshold
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-70 mV what membrane potential (mV) is resting potential?
action If you can get prepotentials into threshold, you can get _______ potential
spontaneous depolarization the rate of this is fastest in the SA node, which generates APs at a rate of ~100/min , and slower in the AV node, ~60 APs/min
pacemaker because the conducting cells of the SA node reach threshold the fastest, the SA node establishes the heart rate = it is the _________
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pacemaker installed in hearts to artificially give that person a speady bpm, and get placed if the person has damage to the SA node
parasympathetic NS If SA node is the pacemaker, then why is resting heart rate usually much slower than 100 bpm? Because __________ slows the heart
AV node If the SA node was damaged, this would now be the fastest and set the pace of the heart at ~60 bpm
parasympathetic NS NS that is always sending signals to slow heart rate
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250 during exercise, your heart rate can get up to _____ bpm.
C. ~20 bpm

All of the following are true of the SA node except for which of the following:

A. pacemaker

B. in right atrium near superior ven cava

C. ~20 bpm

Sinoatrial (SA) node located in the superior and posterior wall of the right atrium, near the entrance of the superior vena cava
SA node contains pacemaker cells that establish the heart rate
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internodal pathways these are conducting cells in the atrial wall that connect the SA node and AV node
contractile in internodal pathways, these conducting cells relay the signal from the SA node to the AV node, they also stimulate _______ cells of both atria to contract
contractile

in internodal pathways, once these cells begin contracting, the action potential spreads across the atrial cells by cell-to-cell contact

*i.e. through the intercalated discs

cardiac skeleton in internodal pathways, the contracting atrial cells do not pass the stimulus to the contractile cells of the ventricles because of the __________, which isolates the atrial myocardium from the ventricular
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atrioventricular (AV) node located in the floor of the right atrium near the right AV valve (tricuspid)
AV node here, the signal is delayed by ~100 msec because the conducting cells here are relatively small in diameter , and there are fewer gap junctions between cells  
delay important in the AV node because it ensures that the atria contract BEFORE the ventricles (i.e. allows the ventricles to fill with blood)
AV bundle (Bundle of His) from the AV node, impulse is conducted to _________
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AV bundle (Bundle of His) this bundle of conducting cells runs from the AV node to the interventricular septum and quickly divides into the bundle branches 
bundle branches occur within the interventricular septum, both branches extend toward the apex, turn, and fan out in opposite directions
left the _____ bundle branch is much larger than the other (because the _____ ventricle is larger)
left the left and right ventricles hold the same amount of blood, but the _____ ventricle is more tough and stronger because it has a longer distance to travel the systemic circuit 
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Bundle branches

these branches conduct the impulses to two places:

  1. to the papillary muscles of the ventricles
  2. Purkinje fibers
     
chordae tendinae bundle branches conduct impulses to the papillary muscles to ensure that the __________ tighten and stabilize the heart valves BEFORE the ventricles start to contract
purkinje fibers spread out from the apex of the heart to the base thus the ventricles begin contracting at the apex, and the contraction spreads in a wave-like fashion toward the base of the heart  
purkinje fibers this pushes blood to the correct direction toward the pulmonary trunk and aorta
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conducting depending on where your heart attack is, one's ________ cells can be damaged as well as muscle.
purkinje fibers differ from other conducting cells in being very large
purkinje fibers because of their large size, they conduct action potentials very quickly thus the signal to contract quickly reaches all the contractile cells of the ventricles, so the ventricles contract in UNISON 
gap junctions from the end of the Purkinje fibers, signal spreads from cardiocyte to cardiocyte through their ________
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conducting cells these cells exhibit prepotentials, they do not have a resting membrane potential and are always drifting upwards
pacemaker in SA node, the prepotentials are called "_________ potential"
spontaneous depolarization this happens when the cell membrane of conducting cells have "leaky" Na+ channels but relatively few "leaky" K+ channels  
neuron conducting cells are opposite of a _______, because conducting cells have more Na+ outside the cell membrane  
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conducting cells these types of cells are specialized muscle cells
conducting cells begin at about -60 mV but doesn't stay still, because Na+ continuously leaks in (and K+ mostly stays put) [=net influx of positive charges]
calcium conducting cells reach threshold at about -40 mV. this causes voltage-gated ____ channels to open where it rushes from the extracellular fluid down its concentration gradient 
calcium _______ is important for bones, muscle, synapses, memory, etc.
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K+ in conducting cells, after the calcium channels open, it spikes to above +0 mV. this opens lots of voltage-gated ____ channels and closes the voltage-gated calcium channel, allowing the excess positive charges to leave and repolarizes back to -60 mV. (cycle repeats)
electrocardiogram recordings of the electrical activites of the heart
electrodes the electrical activities that occur in the heart are powerful enough to be detected by _______ on the surface of the body
electrodes depending on where you position the _______ (aka leads), the appearance of the ECG varies
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P wave

_______: atrial depolarization

*this is a record of the electrical activity, NOT contraction 

QRS complex shows ventricular depolarization when measuring electrical activity and has a stronger signal because the ventricles are more powerful 
T wave shows ventricular repolarization when measuring electrical activity
atrial repolarization there is no wave shown for this when measuring electrical activity because it is "covered up" by the QRS complex  
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ECG's often used to diagnose cardiac arrhythmias
cardiac arrhythmias abnormal patterns of cardiac electrical activity; temporary ones are presumably not dangerous (about 5% have)
arrhythmias

serious ones reduce the heart's pumping efficiency and may indicate:

a. damage to myocardium

b. injuries to the pacemakers or conduction pathways

c. drug exposure

d. electrolyte imbalances 

ECGs measures thte voltage changes and the durations of the various waves
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QRS complex an enlarged heart is often indicated by a stronger _________ than normal
P-Q interval the period from the start of atrial depolarization to the start of the QRS complex 
P-Q interval this indicates the time it takes for the electrical signal to go from the SA node to the AV node
Q-T interval the period from the start of ventricular depolarization to the end of ventricular repolarization
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Q-T interval a prolonged _________ may indicate s potentially life-threatening congenital heart defect
nodal rhythm the type of rhythm when the ECG shows no SA node activity (the P wave is missing)  
AV node if the SA node isn't working, the _______ generates the rhythm
Heart block this is shown on an ECG when signals start at SA node but is blocked before reaching AV node (QRS complex and T waves are missing)
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ventricular fibrillation the most serious pathological ECGs that is often seen in myocardial infarction
defibrillation how much fibrillation be corrected?
blood vessels

five general classes:

  1. arteries
  2. arterioles
  3. capillaries
  4. venules
  5. veins
     
arteries _______-----> Divergence (splitting into smaller and smaller _____ [arterioles])
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veins ______---> convergence (join together or merge)
arteries type of blood vessel that carries blood AWAY from the heart and branches repeatedly into smaller ones, then called arterioles
arterioles the smallest arteries
capillaries blood vessel where nutrient/waste exchange occurs
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veins blood vessels that carry blood TO the heart (merge into larger ones)
venules smallest veins
endothelium the innermost layer of all blood vessels is the endothelial lining (or ________)
endothelium layer of blood vessels that is a simple squamos epithelium, meaning it has a smooth, low-friction surface
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functions

the structure of the different types of blood vessels reflects _______

vessels ______ which have to withstand greater pressures (e.g., arteries closest to the heart) have a thicker, stronger wall
tunica externa the outermost layer of the walls of the arteries and veins that has a connective tissue sheath that blends into surrounding tissues
tunica externa anchors the vessel into the surrounding tissue
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tunica media concentric layers of smooth muscle of the arterial and vein walls
tunica media this muscular layer can relax or contract to change the diameter of the vessel
tunica media layer of the artery and vein walls that is controlled by the autonomic nervous system
external elastic in arteries, the outer margin of the tunica media contains a thin band of elastic fibers called the __________  membrane and is bordered on both sides
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tunica media layer of the artery and vein walls that has the most smooth muscle
tunica intima innermost layer of the artery and vein walls and is in contact with the blood and is composed of simple squamous epithelium
internal elastic in arteries, the outer margin of the tunica intima contains a thick layer of elastic fibers called the ___________ membrane
thicker the walls of arteries are much _______ than veins mainly because the tunica media of arteries contains more smooth muscle and elastic fibers
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tunica media if artery, this layer is bordered by internal and external elastic membrane
arteries closer _______ can withstand to the heart and experiences greater pressure changes making its walls thicker
lumen opening in the center
cross-section in ________, arteries retain their circular shape, but the weaker-walled veins tend to look flattened or distorted
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muscular veins are less _______ than arteries
artery the endothelial lining (endothelium) of an _______ looks rippled when the _______ is CONSTRICTED
expandable veins are much more _______ than arteries
8x for a given rise in blood pressure, a vein will expand ____ more than a corresponding artery
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balloons veins are more like ______, arteries are more like car tires
valves these are not needed in arteries, because it has more blood pressure
arteries this type of blood vessel's thick, muscular walls make them elastic and contractile
elasticity this characteristic helps arteries absorb the pressure changes that occur with the pumping of the ventricles
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contractility this characteristic enables arteries to change in diameter and thus alter both blood flow and blood pressure
shock what happens when there is a sudden drop in blood pressure, making it hard for blood to reach the brain 
aneurysm when pressure is too great, a bulge in the weakened wall of an artery will develop called an:
aneurysm these bulges in the artery wall can actually burst, especially in the aorta (fatal bleeding) and the brain (can cause a stroke)
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capillaries in traveling from the heart to the _________, blood travels first in elastic arteries, then muscular arteries, and finally in arterioles.
elastic arteries the largest arteries, e.g. aorta, pulmonary trunk, and subclavian artery and has a diameter up to 2.5 cm
tunica media in elastic arteries, this layer of the artery and vein walls has especially high density of elastic fibers; thus highly elastic and can withstand great pressure changes that occur close to the heart.
elastic rebound

to some extent, all elastic arteries exhibit "_____________"

a. helps push blood forward

b. and dampens the pressure peaks and valleys such that blood flow is more continuous

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friction if blood gushed in and out instead of a continuous flow, the walls would weaken from all the ________.
muscular arteries

medium sized arteries that distibute blood to skeletal muscles and internal organs

-to pancreas, small intestines, lungs, etc.

tunica media in muscular arteries, walls of the __________ are less elastic and more muscular than in elastic arteries
muscular arteries arteries you can see with the naked eye
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arterioles type of blood vessels that are tiny compared to mucular arteries with a diameter of ~30 um or less
arterioles transports blood from small muscular arteries to the capillaries
arterioles do not have an obvious tunica externa and its tunica media may have only 1-2 or <1 layer of smooth muscle cells
arterioles in most tissues, _________ vasodilate when O2 levels are low and vasoconstrict when sympathetic NS stimulates them 
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vasodilate causes more blood flow to part of body that needs oxygen
vasoconstrict increases blood pressure and pushes blood to muscle (in life threatening situations) 
capillaries the only vessels whose walls permit exchange of substances between the blood and interstitial fluid
capillary substances can quickly diffuse across the ________ walls since the walls are so thin
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capillary beds blood flows slowly the _________, thus giving plenty of time for the exchange of materials
capillary made up of a single layer of endothelium over a thin basement membrane and has no tunica media or externa
capillary has a diameter of about 8 um, very similar to that of a single RBC
continuous capillaries the most common type of capillary where the endothelium is a complete lining and found in all tissues except EPI and cartilage
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continuous capillaries type of capillaries that allow water, small solutes, and hydrophobic fluid, but prevent the loss of blood cells and plasma proteins
continuous capillaries type of capillaries that are specialized in the Blood-Brain Barrier in the brain 
fenestrated capillaries type of capillaries where the endothelial lining has pores
fenestrated capillaries capillaries that allow the exchange of water and solute as large as small peptides
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fenestrated capillaries capillaries common in blood vessls of the endocrine organs (e.g., hypothalamus, pituitary, pineal, thyroid)
sinusoids capillaries that resemble fenestrated capillaries that are flattened and irregularly shaped, but they have large gaps between the endothelial cells
plasma proteins

gaps between the endothelial cell wall of the sinusoids allow solutes as large as ________ to pass through

-occurs in liver, bone marrow, spleen, and many endocrine organs 

liver in this organ, sinusoids allow the _______ cells to secrete plasma proteins into the blood
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capillary beds capillaries function as interconnected networks or webs, called: 
precapillary sphincter the entrance to each capillary is regulated by a ____________, a ring of smooth muscle  
precapillary sphincter when it constricts, blood flow to that specific capillary is slowed or stopped and bloodis therefore diverted into other parts of the capillary bed  
veins collect blood from tissues and organs and return them to the heart
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veins relatively thin-walled (since lower pressures) but in general have larger diameters than arteries
venules the smallest veins, receive blood from capillary beds
tunica externa in both medium sized veins and large veins, this layer of the vein's wall is the thickest 
veins walls are relatively thin, with less smooth muscle in tunica media. because of this, they are much more expandable (distensible) than arteries
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veins since they are so stretchy and expandable, they an hold large amounts of blood
valves in venules and medium sized veins these prevent venous backflow of blood into capillary beds
pressure in venules/veins the _______ is so low that gravity can cause blood to flow backwards
valves greatly limit backward flow of blood by "catching" back-flowing blood
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arteries don't need valves because they have such high blood pressure
veins ______ are often sandwiched between skeletal muscles, when the muscles contract, the ______ get squeezed and blood is pushed toward the heart
standing

when you are ________, gravity makes it hard for blood to go from your feet

-e.g. fainting 

valves

if these weaken, blood will pool in the veins and the veins become grossly swollen

-e.g. varicose veins in legs

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hemorrhoids varicose veins in the walls of the anus, rectum, or both
blood

total _____ volume (~5 liters) is unevenly distributed among arteries, veins, and capillaries

Heart: 7%

Pulmonary circuit: 9%

Systemic arterial system: 13%

Systemic capillaries: 7%

Systemic venous system: 64%

systemic venous system nearly 2/3 of blood is here; within skin, bone marrow, liver, and lungs
veins the systemic venous system holds so much blood because the ______ more easily expand and thus can accomodate larger volumes of blood
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sympathetic if blood volume drops suddenly, e.g. major blood loss (hemorrhaging), the ________ NS stimulates the smooth muscle in medium-sized veins to constrict
venoconstriction systemic veins constrict in a process called _________ that decreases the amount of blood in the venous system and increases volume in the arterial system and capillaries where the blood is more needed
venous reserve constriction of veins in skin, liver, and lungs, allows for a large volume of blood to be redistributed and is normally about 20% of the total blood volume ca be shifted in this way, called: 
blood flow

the __________ through capillary beds is dependent on two major factors:

1. Pressure

2. Resistance

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pressure to keep blood moving, the heart must generate enough _______ to overcome the resistance to blood flow
cardiovascular pressure measure of the force exerted by blood against vessel walls
pressure

there are three basic types:

1. arterial blood pressure

2. capillary hydrostatic pressure (CHP)

3. venous pressure

blood pressure refers to arterial pressure, measured in millimeters of mercury (mm of Hg)
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pressure

the biggest change in _______ is from the aorta to the start of the capillary beds:

Aorta: average BP ~100 mm of Hg

systolic pressure

the pressure in a muscular artery when the left ventricle is in systole (contraction)

~120 mm of Hg is normal

diastolic pressure

the pressure when the left ventricle is in diastole (relaxation)

~80 mm of Hg is normal

capillary hydrostatic pressure the pressure within capillary beds, typically declines along bed from 35 to ~18 mm of Hg
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venous pressure pressure within the venous system is very low, ~18 mm of Hg in venules to only ~2 mm of Hg in venae cavae
140/90 according to the American Heart Association, what would be considered hypertension?
hypertension this level of pressure is bad because it increases the workload on the heart and makes it harder for the ventricles to push blood out
hypertension physically stresses the walls of blood vessels thereby promoting atherosclerosis
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plaque the high blood pressure might tear the endothelium and create scar tissue, focal points for ______ buildup
total peripheral resistance

resistance in the entire cardiovascular system; due to three major factors:

1. vascular resistance

2. viscosity

3. turbulence

vascular resistance the resistance of the blood vessels and the most important factor of total peripheral resistance
vascular resistance resistance due to the friction between flowing blood and the vessel walls
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friction

the amount of _______ itself depends on two major factors:

1. vessel length

2. vessel diameter

vessel length longer vessels have more friction because a greater surface area is in contact with the blood
vessel length

in adults, this is fairly constant and changes as we gain or lose weight

-could lose/gain richly vascularized muscle and/or adipose tissue

vessel length this changes a lot when we are young and growing
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increases if you gain 10 lbs of weight, it adds length to blood vessels, ________ peripheral resistance, and raises BP
vessel diameter the smaller the diameter, the greater the friction; this is because friction has the greatest effect close to the vessel wall
wall in a small vessel, nearly all the blood is close to the ______ and is thus slowed down
center in larger vessels, the blood in the ______ is hardly slowed down at all
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diameter unlike vessel length, this is changing rapidly
resistance vessel diameter has a much stronger affect than vessel length does on ________
2 if two blood vessels have the same diameter, but one is twice as long as the other, the longer vessel has ____ times the resistance
16 if two vessels have the same length, but one has twice the diameter of the other, the narrower vessel has ____ times the resistance
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vascular resistance is really dependent on vessel diameter, not so much on vessel lengh because diameter has a huge affect on resistance, and length doesn't change much in adults, but diameter does.
nervous system cannot control length, but it can readily adjust diameter through vasoconstriction/vasodilation
arterioles most of the peripheral resistance occurs in the _______, which are small in diameter but muscular
diameter by just making  small changes in the _______ of arterioles, the nervous system can have a big effect on resistance and blood flow 
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viscosity thickness ("stickiness") of a liquid
blood ______ viscosity is about 5x that of water and usually remains constant 
viscosity the _______ of blood is mainly due to the presence of blood cells and plasma cells
viscosity affected by a lack of plasma proteins in liver or increased number of blood cells. 
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turbulence

occurs when blood flows in eddies and whirls because of:

1. high flow rates

2. irregular surfaces on vessel walls

3. sudden changes in diameter

diameter sudden changes in _______ happen regularly at heart valves
turbulence increases resistance and slows blood flow
turbulence usually occurs between atria and ventricles but rarely elsewhere unless the vessel wall are damaged (i.e. atherosclerosis) 
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plaques would increase turbulence, decrease diameter, and raise blood pressure
vascular resistance in general, while three factors potentially influence the total resistance in the cardiovascular system (vascular, viscosity, and turbulence), in reality it is mainly ________ (and really vessel diameter)
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List View: Terms & Definitions

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 100,000 beats per dayThe heart never rests, so how many times does it beat per day?
 blood vessels

can be divided into:

  1. pulmonary circuit
  2. systemic circuit
 pulmonary circuitcarries blood to and from the lungs
 systemic curcuittransports blood to and from the rest of the body
 oxygen-richThe right side of the pulmonary circuit carries more _________ blood because it is coming straight from the lungs.
 curcuitsoperate simultaneously
 25 daysthe heart starts beating ~____ days post-conception
 arteries

carry blood away from the heart

*even if unoxygenated

 pulmonary_________ arteries carry oxygen poor blood to the lungs
 capillariesthin-walled, microscopic vessels that connect the smallest arteries to the smallest veins
 capillariesgases, nutrients, and wastes are exchanged with the tissues through the very thin walls of the _________
 pulmonary_________ veins are very richly oxygenated
 right atriumreceives O2-poor blood from the body and passes it to the right ventricle
 Right ventriclepumps blood to the lungs
 left atriumreceives oxygen-rich blood from pulmonary circuit and passes it to the left ventricle
 left ventriclepumps blood into systemic ciruit
 heart attackcaused by a lack of oxygen and blood flow to the heart
 chest pain (angina)caused by short term blockage of blood flow to the heart
 heart murmurcaused by leaking regurgitation of heart valves
 nitrogliserindrug that causes chest to open up and help angina
 cardiac arrhythmiawhen your heart is not beating in proper rhythm and uses a defibrilator
 heartdirectly posterior to the sternum; roughly from the 3rd costal cartilage to the end of the body of sternum
 anterior mediastinumwhere the heart lies; space between 2 lungs
 thymusthe endocrine structure in the anterior mediastinum and is the gland deepest to sternum
 basethe _______ of the heart refers to the attached superior end
 apexthe heart is tilted such that the ______ is about 3 inches left of the midline of the body
 rightthe heart is also rotated such that in an anterior view of the body, we see mainly the _______ atrium and _______ ventricle
 pericardium

the fibrous sac that surrounds the heart; consists of two layers:

  1. parietal paricardium
  2. visceral paricardium (aka epicadium)
 parietal pericardiumthe outer layer of the pericardium that consists of dense irregular and areolar CT with an inner lining of simple squamos EPI
 dense irregulartype of connective tissue in the parietal pericardium that resists stretching
 simple squamous EPItype of EPI that makes up the inner lining of the parietal pericardium that reduces friction
 visceral pericardium(aka epicardium) the inner layer of the pericardium that clings to the heart
 histaminethe release of this causes inflammation (swelling)
 pericardial cavitythe potential space between the parietal and visceral layers and contains pericardial fluid
 pericardial fluidlubricating fluid in the pericardial cavity that reduces friction between the beating heart and the surrounding tissues
 pericarditisinflammation on the pericardium and increases friction, e.g. due to infection of trauma
 pericarditiswhen this is present, doctors can actually hear a scratching noise with a stethoscope
 epicardiumoutermost layer of the heart wall (same as the visceral pericardium) that consists of an outer layer of simple squamous EPI over an inner layer of areolar CT that clings to the myocardium
 myocardiumthe muscular wall of the heart that forms both the atria and ventricles
 nervescontrols power of contraction in tissue
 myocardiumlayer of the heart wall that is composed of cardiac muscle tissue, blood vessels, and nerves
 myocardiumlayer of the heart that consists of concentric (nesting) layers of muscle tissue
 endocardiumthe innermost layer of the heart wall
 endocardiuma simple squamous EPI that is continuous with the inner lining of the large blood vessels that attach to the heart and has very little turbulence
 cadiac musclelike skeletal muscle, it is striated and made up of myofibrils (with sacromeres)
 sacromeresmade up of Z-discs
 cardiac musclesunlike skeletal muscles, they are quite small and usually uninucleate
 skeletal muscleincredibly long compared to cardiac muscle, 5-10 times bigger. cells fuse together early, causing this muscle to be multinucleated.
 mitochondria

uses oxygen to generate ATP

 slow______-twitch muscle is created for long-term use
 cardiac muscle cellsthese cells have more mitochondria and the mitochondira are HUGE (make up ~25% of cell volume), have lots of myoglobin, and are even more richly vascularized than average skeletal muscle
 myoglobinstores oxygen in cardiac muscle cells
 cardiac muscle cellswider, but shorter T-tubules and less sarcoplasmic reticulum than skeletal muscle
 calciumin skeletal muscle, the trigger for contraction is the release of _______ from the sarcoplasmic reticulum
 T-tubulesin cardiac muscles, the trigger of contraction also involves the influx of calcium into the cell through these larger ________
 T-tubulesallow change in electrical charge and calcium is released from the sarcoplasmic reticulum
 cardiocytesare typically branched
 intercalated discscardioctyes are connected to several other cardiocytes at special sites called:
 interdigitating foldsthe bumpy surface at the ends of the cells that increase the surface area for cell-cell connections
 plasmathe _______ membranes of adjacent cells are joined by desmosomes and gap junctions
 desmosomesresist stretching and help transfer the force of contraction from cell to cell
 gap junctionsallow small molecules and ions to flow between the cells thereby electrically connecting the cells
 action potentials___________ can quickly travel from cell to cell through the gap junctions
 gap junctionsin a sense, they allow the cardiocytes of the two atria to act like a single, huge cell
 autorhythmicthe tissue contracts without neural stimulation 
 pacemaker cellthe timing of contractions is controlled by this special type of muscle cell 
 contractionmotor neurons can influence the pacemaker and the force of ________
 cardiac muscle tissuetissue that is totally dependent on aerobic metabolism (respiration)
-hence lots of large mitochondria and myoglobin
 fatiguecardiac muscle does not readily ________
 twitches________ do not sum up in cardiac muscle as in skeletal muscle; therefore, the heart cannot produce a sustained contraction 
 cardiac muscle tissuethis type of muscle tissue is beneficial because if the heart became locked in a sustained contraction, it couldn't pump blood. 
-slow twitch=high stamina
 Right atriumthe path of blood through the heart starts here; it receives blood from the systemic circuit through the two great veins: superior & inferior vena cava 
 superior vena cavagreat vein that connects to the superior right atrium and carries deoxygenated blood from the upper body 
 inferior vena cavagreat vein that connects to the inferior right atrium and carries deoxygenated blood from the lower body
 auriclewhen not filled with blood, the outer portion of each atrium (both right and left) deflates into a wrinkly flap called the ________ ("ear")
 interatrial septumthe relatively thin wall separating the right and left atria
 foramen ovalefrom early embryonic development until birth, there's an oval opening, called the _____________, through the interatrial septum that connects the right and left atria
 foramen ovalethis was beneficial before birth because it bypasses lungs
 fossa ovalisafter closing, the foramen ovale becomes the ___________, a small, shallow depression that persists into adulthood 
 Right ventricleblood flows from the right atrium through the right atrioventricular (AV) valve into the ___________
 cuspsfibrous flaps 
 right atrioventricular (AV) valveaka Tricuspid valve; has three cusps that are connected to chordae tendinae originating at the papillary muscles
 chordae tendinaethe free edge of each cusp is attached to connective tissue fibers called the __________ that originate at the papillary muscles and stabilize valves
 papillary muscleswhere the chordinae tendinae originate; are conical muscular projections from the inner surface of the right ventricle 
 contractswhen the right ventricle __________, the right AV valve closes and prevents the backflow of blood into the right atrium
 chordae tendinaeprevents overextension of the cusps 
(e.g. prevent them from acting like swinging doors)
 trabeculae carneaethe inner surface of the ventricle has a series of muscular ridges called the:
 pulmonary circuitwhen the right ventricle contracts, it pumps blood through the pulmonary semilunar valve to enter the pulmonary trunk, which starts the _____________
 pulmonary semilunar valvethese valves are called "semilunar" because the cusps have a half-moon shape and they prevent backflow of blood into the right ventricle upon relaxation of the ventricle 
 pulmonary arteriesDuring the pulmonary circuit, the pulmonary trunk quickly divided into the right and left ____________
 pulmonary arteriesthese arteries divide into smaller and smaller branches until they deliver blood to the delicate gas-exchange sites of the lungs
 pulmonary veinsduring the pulmonary circuit, after the exchange of gases in the lungs, oxygenated blood flow into the right and left ______________
 left atriumthe right and left pulmonary veins deliver blood to the:
 left ventricleblood flows from the left atrium through the left atrioventricular (AV) valve into the:
 interventricular septuma thick wall separating the right and left ventricles 
 left atrioventricular (AV) valveaka Bicuspid or Mitral valve; has only two cusps and also works via chordae tendinae and papillary muscles 
 left atriumwhen the left ventricle contracts, the left AV valve closes and prevents the backflow of blood into the:
 ascending aortablood is pumped by the strong left ventricle through the aortic semilunar valve into the: 
 left ventriclethe right and left ventricles hold equal amounts of blood, but the ______ ventricle has much thicker walls, making it more muscular
 ademawhen you have unequal blood flow, you have swelling (________) that could create blockage and ruin pump.
 pressurethe thicker, stronger walls enable the left ventricle to pump with much greater _______ than the right ventricle
 right ventriclethis ventricle only has to pump blood at low pressure a short distance (~6 inches)
 left ventriclethis ventricle has to pump blood throughout the systemic circuit and requires as much as 5x as much as the other ventricle
 interventricular septumwhen the right ventricle contracts, it acts like a "bellows" and squeezes blood against the thick ____________
 contractionshappen simultaneously 
 right ventriclethis ventricle has a pouch-like shape
 leftwhen the powerful _______ ventricle contracts, all of its walls contract such that the ventricle both shortens in length (from apex to base) and decreases in diameter
 left ventriclethis ventricle is round in cross-section 
 contractswhen the left ventricle ________, it bulges into the right ventricular cavity and helps the right ventricle do its job 
 heart beatthis is created when the atria contract simultaneously and then the ventricles contract simultaneously sending equal volumes of blood to pulmonary and systemic circuits
 valvesheart _______ permit blood to flow in one direction only
 atrioventricular valvesvalves that prevent blood from being forced backed into atria when ventricles contract, and without them, pumping efficiency would be very poor  
 ventricleswith the _______ contract. blood moving back toward the atria swings the cusps of the valves together, sealing the valve 
 chordae tendinaea split second before the ventricles contract, the papillary muscles contract and tighten the __________ thereby preventing the cusps from swinging into the atria 
 papillary muscleif these were damaged, each time ventricles contract, there would be backflow (regurgitation) into the atria 
 semilunar valvesvalves that prevent the blood from leaking back into the ventricles when the ventricles are relaxed 
 semilunar valvesunlike the AV valves, these valves neither have nor need muscular braces because the pressure they need to withstand is much less (after all, the ventricles are relaxed)  
 semilunar valveeach has three cusps that brace each other in the closed position 
 valvular heart disease (VHD)occurs if the valves malfunction to the extent that the heart cannot pump efficiently 
 carditissometimes valves are faulty at birth, but often faulty valves develop after ________ (inflammation of the heart) occurs 
 cardiac skeletonaka fibrous skeleton; consists of four dense bands of tissue that encircle the heart valves as well as the bases of the aorta and pulmonary trunk
 bandsthe _______ of the cardiac skeleton stabilize the heart valves and the bases of the great vessels 
 cardiac skeletonelectrically insulate the cardiac cells of the ventricles from those of the atria and helps not to pump out of rhythm 
 heartlots of collagen and elastic fibers support the structure of the ______
 cardiac muscle celleach of these muscle cells are wrapped in a strong, but elastic, sheath 
 cross-linkswhat neighboring cells are "tied" together by in the connective tissue of the heart 
 connective tissues
  • physically supports the muscle cells, nerve cells, and blood vessels of the heart 
  • prevent overexpansion of the heart 
  • help heart "spring" back into its original size after contracting
  • help distribute the force of contraction
 connective tissuehelps distribute the force of contraction so that one area doesn't suffer most of the wear and tear 
 heartweighs less than 1% of your total body weight and gets 5% of your total blood 
 heartsince this organ is constantly active, its muscle cells need lots of oxygen and nutrients therefore it needs to send itself a large amount of blood 
 coronary circulationthe blood supply to the heart is called the:
 coronarythe _______ arteries (right and left) emerge from the base of the aorta
 coronary arteriesthese arteries emerge very close to the aortic semilunar valve 
 relaxationblood only enters coronary arteries during _________
 coronarywhen the left ventricle contracts, it forces blood into the aorta, but little blood flows into the ________ arteries, because the cusps of the valves block them
 recoilwhen the ventricle relaxes, the stretched walls of the aorta relax and _______: (aka elastic rebound) both pushes blood further into the systemic circuit and into to coronary arteries 
 coronary arteriesare among the most variable aspects of all human anatomy
 right coronary arterysupplies blood to the right atrium and the right ventricle 
 Posterior interventricular branchbranch of the RCA that supplies blood to both posterior ventricles
 left coronary arteryruns along margin of the left atrium; quickly splits into two major branches:
  1. circumflex branch 
  2. anterior interventricular (descending) branch
 circumflex branchbranch of the LCA that supplies blood to the left atrium and posterior ventricle 
 anterior interventricular (descending) branchbranch of the LCA that supplies blood to both ventricles
 anastomosisthe anterior interventricular branch of the LCA eventually joins to the posterior interventricular branch of the LCA; such a convergence is called an __________
 anastomosisthis is helpful because it gives you an alternate blood flow route
 great cardiac veinvein that drains blood from the anterior heart and runs alongside the anterior interventricular branch of the LCA
 Middle cardiac veinaka posterior interventricular vein; drains blood from the posterior heart and runs alongside the posterior interventricular branch of the RCA 
 Small cardiac veinvein that drains blood from posterior right atrium and runs alongside the RCA and posterior right atrium 
 coronary sinusall the cardiac veins empty into this which, in turn, empties into the right atrium and has a large, thin-walled vein on the posterior of the heart
 heart attacks(myocardial infarctions, MI) account for ~50% of all deaths in the US
 heart attackscaused by a long-term insufficient supply of blood to one or more parts of the heart muscle that suddenly kills a patch of the myocardium 
 infarctionsdeath of tissue due to a stoppage of blood flow
 coronary arteriesthe poor blood supply is usually due to a blood clot or atherosclerosis of the ____________ 
 heart attackpatients may recover from this if the damage to the heart is small enough such that the heart can still pump efficiently, but typically the MI weakens the muscle and/or disrupts the conduction of electrical signals
 atherosclorosisaccumulation of fatty tissue that blocks the artery 
 angina pectoris"chest pain" : a sense of heaviness or pain in the chest and often the left arm and shoulder and is caused by a SHORT TERM slow down or blockage of blood flow 
-e.g. a partially blocked coronary artery constricts temporarily 
 angina pectorisduring _________, when the artery dilates, or relaxes, the artery releases and goes back to normal 
 anaerobic fermentationwith insufficient blood and oxygen, the cardiocytes switch to ____________ during angina pectoris 
 chest painthe warning sign that the blood supply is weak to the heart  
 resumesthe chest pain during angina pectoris will abate when blood flow _______
 conducting systema network of specialized cardiac muscle cells that initiates and distributes the electrical impulses through the heart that stimulate the heart to contract 
 cardiacsince it has its own conducting system, _______ muscle contracts on its own and does not require neural stimulation; it's autorhythmic (unlike skeletal muscle) 
 cardiac muscle cellstwo types of these cells are involved in a normal heartbeat:
a. contractile cells
b.  conducting cells
 contractile cellsthe muscle cells that actually contract and propel the blood 
-e.g. actin and myosin
 conducting cellsspecialized muscle cells which coordinate the contraction
-i.e. they make sure the contractile cells push blood in the correct direction and at the correct time 
 conducting cellstypically smaller than the contractile cells and have few myofibrils
 contractionin cardiac muscle, the actual _________ lags behind the electrical stimulation (similar to skeletal muscle)   
 calcium, troponinbecause the electrical impulse has to spread throughout the cardiocyte, _______ has to be released from the sarcoplasmic reticulum and bind to _______, which finally uncover the binding sites etc.
 binding siteswhere strands of myosin bind to actin receptors 
 components of the conducting system
  1. Sinoatrial (SA) node
  2. Internodal pathways
  3. Atrioventricular (AV) node
  4. AV bundle (Bundle of His)
  5. Bundle Branches
  6. Purkinje fibers 
 prepotentialsthe conducting cells of both nodes (SA and AV) exhibit _______
 prepotentialsaka pacemaker potential; a gradual depolarization; in other words, the cell membranes of these conducting cells cannot maintain a stable resting potential  
 positivethe potential of both nodes (SA and AV) drift more _______ toward threshold
 -70 mVwhat membrane potential (mV) is resting potential?
 actionIf you can get prepotentials into threshold, you can get _______ potential
 spontaneous depolarizationthe rate of this is fastest in the SA node, which generates APs at a rate of ~100/min , and slower in the AV node, ~60 APs/min
 pacemakerbecause the conducting cells of the SA node reach threshold the fastest, the SA node establishes the heart rate = it is the _________
 pacemakerinstalled in hearts to artificially give that person a speady bpm, and get placed if the person has damage to the SA node
 parasympathetic NSIf SA node is the pacemaker, then why is resting heart rate usually much slower than 100 bpm? Because __________ slows the heart
 AV nodeIf the SA node was damaged, this would now be the fastest and set the pace of the heart at ~60 bpm
 parasympathetic NSNS that is always sending signals to slow heart rate
 250during exercise, your heart rate can get up to _____ bpm.
 C. ~20 bpm

All of the following are true of the SA node except for which of the following:

A. pacemaker

B. in right atrium near superior ven cava

C. ~20 bpm

 Sinoatrial (SA) nodelocated in the superior and posterior wall of the right atrium, near the entrance of the superior vena cava
 SA nodecontains pacemaker cells that establish the heart rate
 internodal pathwaysthese are conducting cells in the atrial wall that connect the SA node and AV node
 contractilein internodal pathways, these conducting cells relay the signal from the SA node to the AV node, they also stimulate _______ cells of both atria to contract
 contractile

in internodal pathways, once these cells begin contracting, the action potential spreads across the atrial cells by cell-to-cell contact

*i.e. through the intercalated discs

 cardiac skeletonin internodal pathways, the contracting atrial cells do not pass the stimulus to the contractile cells of the ventricles because of the __________, which isolates the atrial myocardium from the ventricular
 atrioventricular (AV) nodelocated in the floor of the right atrium near the right AV valve (tricuspid)
 AV nodehere, the signal is delayed by ~100 msec because the conducting cells here are relatively small in diameter , and there are fewer gap junctions between cells  
 delayimportant in the AV node because it ensures that the atria contract BEFORE the ventricles (i.e. allows the ventricles to fill with blood)
 AV bundle (Bundle of His)from the AV node, impulse is conducted to _________
 AV bundle (Bundle of His)this bundle of conducting cells runs from the AV node to the interventricular septum and quickly divides into the bundle branches 
 bundle branchesoccur within the interventricular septum, both branches extend toward the apex, turn, and fan out in opposite directions
 leftthe _____ bundle branch is much larger than the other (because the _____ ventricle is larger)
 leftthe left and right ventricles hold the same amount of blood, but the _____ ventricle is more tough and stronger because it has a longer distance to travel the systemic circuit 
 Bundle branches

these branches conduct the impulses to two places:

  1. to the papillary muscles of the ventricles
  2. Purkinje fibers
     
 chordae tendinaebundle branches conduct impulses to the papillary muscles to ensure that the __________ tighten and stabilize the heart valves BEFORE the ventricles start to contract
 purkinje fibersspread out from the apex of the heart to the base thus the ventricles begin contracting at the apex, and the contraction spreads in a wave-like fashion toward the base of the heart  
 purkinje fibersthis pushes blood to the correct direction toward the pulmonary trunk and aorta
 conductingdepending on where your heart attack is, one's ________ cells can be damaged as well as muscle.
 purkinje fibersdiffer from other conducting cells in being very large
 purkinje fibersbecause of their large size, they conduct action potentials very quickly thus the signal to contract quickly reaches all the contractile cells of the ventricles, so the ventricles contract in UNISON 
 gap junctionsfrom the end of the Purkinje fibers, signal spreads from cardiocyte to cardiocyte through their ________
 conducting cellsthese cells exhibit prepotentials, they do not have a resting membrane potential and are always drifting upwards
 pacemakerin SA node, the prepotentials are called "_________ potential"
 spontaneous depolarizationthis happens when the cell membrane of conducting cells have "leaky" Na+ channels but relatively few "leaky" K+ channels  
 neuronconducting cells are opposite of a _______, because conducting cells have more Na+ outside the cell membrane  
 conducting cellsthese types of cells are specialized muscle cells
 conducting cellsbegin at about -60 mV but doesn't stay still, because Na+ continuously leaks in (and K+ mostly stays put) [=net influx of positive charges]
 calciumconducting cells reach threshold at about -40 mV. this causes voltage-gated ____ channels to open where it rushes from the extracellular fluid down its concentration gradient 
 calcium_______ is important for bones, muscle, synapses, memory, etc.
 K+in conducting cells, after the calcium channels open, it spikes to above +0 mV. this opens lots of voltage-gated ____ channels and closes the voltage-gated calcium channel, allowing the excess positive charges to leave and repolarizes back to -60 mV. (cycle repeats)
 electrocardiogramrecordings of the electrical activites of the heart
 electrodesthe electrical activities that occur in the heart are powerful enough to be detected by _______ on the surface of the body
 electrodesdepending on where you position the _______ (aka leads), the appearance of the ECG varies
 P wave

_______: atrial depolarization

*this is a record of the electrical activity, NOT contraction 

 QRS complexshows ventricular depolarization when measuring electrical activity and has a stronger signal because the ventricles are more powerful 
 T waveshows ventricular repolarization when measuring electrical activity
 atrial repolarizationthere is no wave shown for this when measuring electrical activity because it is "covered up" by the QRS complex  
 ECG'soften used to diagnose cardiac arrhythmias
 cardiac arrhythmiasabnormal patterns of cardiac electrical activity; temporary ones are presumably not dangerous (about 5% have)
 arrhythmias

serious ones reduce the heart's pumping efficiency and may indicate:

a. damage to myocardium

b. injuries to the pacemakers or conduction pathways

c. drug exposure

d. electrolyte imbalances 

 ECGsmeasures thte voltage changes and the durations of the various waves
 QRS complexan enlarged heart is often indicated by a stronger _________ than normal
 P-Q intervalthe period from the start of atrial depolarization to the start of the QRS complex 
 P-Q intervalthis indicates the time it takes for the electrical signal to go from the SA node to the AV node
 Q-T intervalthe period from the start of ventricular depolarization to the end of ventricular repolarization
 Q-T intervala prolonged _________ may indicate s potentially life-threatening congenital heart defect
 nodal rhythmthe type of rhythm when the ECG shows no SA node activity (the P wave is missing)  
 AV nodeif the SA node isn't working, the _______ generates the rhythm
 Heart blockthis is shown on an ECG when signals start at SA node but is blocked before reaching AV node (QRS complex and T waves are missing)
 ventricular fibrillationthe most serious pathological ECGs that is often seen in myocardial infarction
 defibrillationhow much fibrillation be corrected?
 blood vessels

five general classes:

  1. arteries
  2. arterioles
  3. capillaries
  4. venules
  5. veins
     
 arteries_______-----> Divergence (splitting into smaller and smaller _____ [arterioles])
 veins______---> convergence (join together or merge)
 arteriestype of blood vessel that carries blood AWAY from the heart and branches repeatedly into smaller ones, then called arterioles
 arteriolesthe smallest arteries
 capillariesblood vessel where nutrient/waste exchange occurs
 veinsblood vessels that carry blood TO the heart (merge into larger ones)
 venulessmallest veins
 endotheliumthe innermost layer of all blood vessels is the endothelial lining (or ________)
 endotheliumlayer of blood vessels that is a simple squamos epithelium, meaning it has a smooth, low-friction surface
 functions

the structure of the different types of blood vessels reflects _______

 vessels______ which have to withstand greater pressures (e.g., arteries closest to the heart) have a thicker, stronger wall
 tunica externathe outermost layer of the walls of the arteries and veins that has a connective tissue sheath that blends into surrounding tissues
 tunica externaanchors the vessel into the surrounding tissue
 tunica mediaconcentric layers of smooth muscle of the arterial and vein walls
 tunica mediathis muscular layer can relax or contract to change the diameter of the vessel
 tunica medialayer of the artery and vein walls that is controlled by the autonomic nervous system
 external elasticin arteries, the outer margin of the tunica media contains a thin band of elastic fibers called the __________  membrane and is bordered on both sides
 tunica medialayer of the artery and vein walls that has the most smooth muscle
 tunica intimainnermost layer of the artery and vein walls and is in contact with the blood and is composed of simple squamous epithelium
 internal elasticin arteries, the outer margin of the tunica intima contains a thick layer of elastic fibers called the ___________ membrane
 thickerthe walls of arteries are much _______ than veins mainly because the tunica media of arteries contains more smooth muscle and elastic fibers
 tunica mediaif artery, this layer is bordered by internal and external elastic membrane
 arteriescloser _______ can withstand to the heart and experiences greater pressure changes making its walls thicker
 lumenopening in the center
 cross-sectionin ________, arteries retain their circular shape, but the weaker-walled veins tend to look flattened or distorted
 muscularveins are less _______ than arteries
 arterythe endothelial lining (endothelium) of an _______ looks rippled when the _______ is CONSTRICTED
 expandableveins are much more _______ than arteries
 8xfor a given rise in blood pressure, a vein will expand ____ more than a corresponding artery
 balloonsveins are more like ______, arteries are more like car tires
 valvesthese are not needed in arteries, because it has more blood pressure
 arteriesthis type of blood vessel's thick, muscular walls make them elastic and contractile
 elasticitythis characteristic helps arteries absorb the pressure changes that occur with the pumping of the ventricles
 contractilitythis characteristic enables arteries to change in diameter and thus alter both blood flow and blood pressure
 shockwhat happens when there is a sudden drop in blood pressure, making it hard for blood to reach the brain 
 aneurysmwhen pressure is too great, a bulge in the weakened wall of an artery will develop called an:
 aneurysmthese bulges in the artery wall can actually burst, especially in the aorta (fatal bleeding) and the brain (can cause a stroke)
 capillariesin traveling from the heart to the _________, blood travels first in elastic arteries, then muscular arteries, and finally in arterioles.
 elastic arteriesthe largest arteries, e.g. aorta, pulmonary trunk, and subclavian artery and has a diameter up to 2.5 cm
 tunica mediain elastic arteries, this layer of the artery and vein walls has especially high density of elastic fibers; thus highly elastic and can withstand great pressure changes that occur close to the heart.
 elastic rebound

to some extent, all elastic arteries exhibit "_____________"

a. helps push blood forward

b. and dampens the pressure peaks and valleys such that blood flow is more continuous

 frictionif blood gushed in and out instead of a continuous flow, the walls would weaken from all the ________.
 muscular arteries

medium sized arteries that distibute blood to skeletal muscles and internal organs

-to pancreas, small intestines, lungs, etc.

 tunica mediain muscular arteries, walls of the __________ are less elastic and more muscular than in elastic arteries
 muscular arteriesarteries you can see with the naked eye
 arteriolestype of blood vessels that are tiny compared to mucular arteries with a diameter of ~30 um or less
 arteriolestransports blood from small muscular arteries to the capillaries
 arteriolesdo not have an obvious tunica externa and its tunica media may have only 1-2 or <1 layer of smooth muscle cells
 arteriolesin most tissues, _________ vasodilate when O2 levels are low and vasoconstrict when sympathetic NS stimulates them 
 vasodilatecauses more blood flow to part of body that needs oxygen
 vasoconstrictincreases blood pressure and pushes blood to muscle (in life threatening situations) 
 capillariesthe only vessels whose walls permit exchange of substances between the blood and interstitial fluid
 capillarysubstances can quickly diffuse across the ________ walls since the walls are so thin
 capillary bedsblood flows slowly the _________, thus giving plenty of time for the exchange of materials
 capillarymade up of a single layer of endothelium over a thin basement membrane and has no tunica media or externa
 capillaryhas a diameter of about 8 um, very similar to that of a single RBC
 continuous capillariesthe most common type of capillary where the endothelium is a complete lining and found in all tissues except EPI and cartilage
 continuous capillariestype of capillaries that allow water, small solutes, and hydrophobic fluid, but prevent the loss of blood cells and plasma proteins
 continuous capillariestype of capillaries that are specialized in the Blood-Brain Barrier in the brain 
 fenestrated capillariestype of capillaries where the endothelial lining has pores
 fenestrated capillariescapillaries that allow the exchange of water and solute as large as small peptides
 fenestrated capillariescapillaries common in blood vessls of the endocrine organs (e.g., hypothalamus, pituitary, pineal, thyroid)
 sinusoidscapillaries that resemble fenestrated capillaries that are flattened and irregularly shaped, but they have large gaps between the endothelial cells
 plasma proteins

gaps between the endothelial cell wall of the sinusoids allow solutes as large as ________ to pass through

-occurs in liver, bone marrow, spleen, and many endocrine organs 

 liverin this organ, sinusoids allow the _______ cells to secrete plasma proteins into the blood
 capillary bedscapillaries function as interconnected networks or webs, called: 
 precapillary sphincterthe entrance to each capillary is regulated by a ____________, a ring of smooth muscle  
 precapillary sphincterwhen it constricts, blood flow to that specific capillary is slowed or stopped and bloodis therefore diverted into other parts of the capillary bed  
 veinscollect blood from tissues and organs and return them to the heart
 veinsrelatively thin-walled (since lower pressures) but in general have larger diameters than arteries
 venulesthe smallest veins, receive blood from capillary beds
 tunica externain both medium sized veins and large veins, this layer of the vein's wall is the thickest 
 veinswalls are relatively thin, with less smooth muscle in tunica media. because of this, they are much more expandable (distensible) than arteries
 veinssince they are so stretchy and expandable, they an hold large amounts of blood
 valvesin venules and medium sized veins these prevent venous backflow of blood into capillary beds
 pressurein venules/veins the _______ is so low that gravity can cause blood to flow backwards
 valvesgreatly limit backward flow of blood by "catching" back-flowing blood
 arteriesdon't need valves because they have such high blood pressure
 veins______ are often sandwiched between skeletal muscles, when the muscles contract, the ______ get squeezed and blood is pushed toward the heart
 standing

when you are ________, gravity makes it hard for blood to go from your feet

-e.g. fainting 

 valves

if these weaken, blood will pool in the veins and the veins become grossly swollen

-e.g. varicose veins in legs

 hemorrhoidsvaricose veins in the walls of the anus, rectum, or both
 blood

total _____ volume (~5 liters) is unevenly distributed among arteries, veins, and capillaries

Heart: 7%

Pulmonary circuit: 9%

Systemic arterial system: 13%

Systemic capillaries: 7%

Systemic venous system: 64%

 systemic venous systemnearly 2/3 of blood is here; within skin, bone marrow, liver, and lungs
 veinsthe systemic venous system holds so much blood because the ______ more easily expand and thus can accomodate larger volumes of blood
 sympatheticif blood volume drops suddenly, e.g. major blood loss (hemorrhaging), the ________ NS stimulates the smooth muscle in medium-sized veins to constrict
 venoconstrictionsystemic veins constrict in a process called _________ that decreases the amount of blood in the venous system and increases volume in the arterial system and capillaries where the blood is more needed
 venous reserveconstriction of veins in skin, liver, and lungs, allows for a large volume of blood to be redistributed and is normally about 20% of the total blood volume ca be shifted in this way, called: 
 blood flow

the __________ through capillary beds is dependent on two major factors:

1. Pressure

2. Resistance

 pressureto keep blood moving, the heart must generate enough _______ to overcome the resistance to blood flow
 cardiovascular pressuremeasure of the force exerted by blood against vessel walls
 pressure

there are three basic types:

1. arterial blood pressure

2. capillary hydrostatic pressure (CHP)

3. venous pressure

 blood pressurerefers to arterial pressure, measured in millimeters of mercury (mm of Hg)
 pressure

the biggest change in _______ is from the aorta to the start of the capillary beds:

Aorta: average BP ~100 mm of Hg

 systolic pressure

the pressure in a muscular artery when the left ventricle is in systole (contraction)

~120 mm of Hg is normal

 diastolic pressure

the pressure when the left ventricle is in diastole (relaxation)

~80 mm of Hg is normal

 capillary hydrostatic pressurethe pressure within capillary beds, typically declines along bed from 35 to ~18 mm of Hg
 venous pressurepressure within the venous system is very low, ~18 mm of Hg in venules to only ~2 mm of Hg in venae cavae
 140/90according to the American Heart Association, what would be considered hypertension?
 hypertensionthis level of pressure is bad because it increases the workload on the heart and makes it harder for the ventricles to push blood out
 hypertensionphysically stresses the walls of blood vessels thereby promoting atherosclerosis
 plaquethe high blood pressure might tear the endothelium and create scar tissue, focal points for ______ buildup
 total peripheral resistance

resistance in the entire cardiovascular system; due to three major factors:

1. vascular resistance

2. viscosity

3. turbulence

 vascular resistancethe resistance of the blood vessels and the most important factor of total peripheral resistance
 vascular resistanceresistance due to the friction between flowing blood and the vessel walls
 friction

the amount of _______ itself depends on two major factors:

1. vessel length

2. vessel diameter

 vessel lengthlonger vessels have more friction because a greater surface area is in contact with the blood
 vessel length

in adults, this is fairly constant and changes as we gain or lose weight

-could lose/gain richly vascularized muscle and/or adipose tissue

 vessel lengththis changes a lot when we are young and growing
 increasesif you gain 10 lbs of weight, it adds length to blood vessels, ________ peripheral resistance, and raises BP
 vessel diameterthe smaller the diameter, the greater the friction; this is because friction has the greatest effect close to the vessel wall
 wallin a small vessel, nearly all the blood is close to the ______ and is thus slowed down
 centerin larger vessels, the blood in the ______ is hardly slowed down at all
 diameterunlike vessel length, this is changing rapidly
 resistancevessel diameter has a much stronger affect than vessel length does on ________
 2if two blood vessels have the same diameter, but one is twice as long as the other, the longer vessel has ____ times the resistance
 16if two vessels have the same length, but one has twice the diameter of the other, the narrower vessel has ____ times the resistance
 vascular resistanceis really dependent on vessel diameter, not so much on vessel lengh because diameter has a huge affect on resistance, and length doesn't change much in adults, but diameter does.
 nervous systemcannot control length, but it can readily adjust diameter through vasoconstriction/vasodilation
 arteriolesmost of the peripheral resistance occurs in the _______, which are small in diameter but muscular
 diameterby just making  small changes in the _______ of arterioles, the nervous system can have a big effect on resistance and blood flow 
 viscositythickness ("stickiness") of a liquid
 blood______ viscosity is about 5x that of water and usually remains constant 
 viscositythe _______ of blood is mainly due to the presence of blood cells and plasma cells
 viscosityaffected by a lack of plasma proteins in liver or increased number of blood cells. 
 turbulence

occurs when blood flows in eddies and whirls because of:

1. high flow rates

2. irregular surfaces on vessel walls

3. sudden changes in diameter

 diametersudden changes in _______ happen regularly at heart valves
 turbulenceincreases resistance and slows blood flow
 turbulenceusually occurs between atria and ventricles but rarely elsewhere unless the vessel wall are damaged (i.e. atherosclerosis) 
 plaqueswould increase turbulence, decrease diameter, and raise blood pressure
 vascular resistancein general, while three factors potentially influence the total resistance in the cardiovascular system (vascular, viscosity, and turbulence), in reality it is mainly ________ (and really vessel diameter)
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