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232 Cards in this Set
- Front
- Back
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is cardiac muscle striated?
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yes
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does cardiac muscle have intercalated disks?
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yes
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does cardiac muscle have fibers composed of cells?
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yes
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do the fibers in cardiac muscle branch?
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yes
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are their spaces between the fibers in cardiac muscle?
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yes
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is skeletal muscle striated?
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yes
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are there intercalated disks in skeletal muscle>
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no
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does skeletal muscle have fibers composed of cells?
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no cells
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do the fibers in skeletal muscle branch?
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yes
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are there spaces between the fibers in skeletal muscle?
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no
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is cardiac muscle striated?
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yes
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does cardiac muscle have intercalated disks?
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yes
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does cardiac muscle have fibers composed of cells?
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yes
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do the fibers in cardiac muscle branch?
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yes
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are their spaces between the fibers in cardiac muscle?
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yes
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is skeletal muscle striated?
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yes
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are there intercalated disks in skeletal muscle>
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no
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does skeletal muscle have fibers composed of cells?
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no cells
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do the fibers in skeletal muscle branch?
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yes
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are there spaces between the fibers in skeletal muscle?
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no
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what nervous system controls cardiac muscle?
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ANS
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what nervous system controls skeletal muscle?
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Somatic NS
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are smooth muscles striated?
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no
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do smooth muscles have intercalated disks?
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no
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do smooth muscles have cells with fibers?
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cells, no fibers
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does smooth msucle have fibers that branch?
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no fibers so no branching
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what system controls smooth muscle?
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ANS
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are atrial and ventrilcular deplaorizations long?
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yes
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do the depolarizations of the atria and ventricle have a plateau?
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yes
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what causes the longer action potential and plateua effect in cardiac tissue?
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fast Na+ channels, slow Ca++ channels
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do the slow Ca++ channels in cardiac muscle stay open longer than the fast Na+ channels? what effect does this help cause?
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yes
plateau effect |
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in cardiac muscle, which channles open 1st in the plateau effect? and what does this allow?
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NA+ channels open, allows NA+ ions to flow in
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in cardiac muscle, what channels open 2nd in the plateau effect? and what happens then?
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Ca++ channels
both channels are open for a time, allowing normal inflow of positive ions |
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in cardiac muscle, do the Ca++ channles remain open once the Na+ channels have cloased? what happens?
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yes
positive ions continue to flow in, even though Na+ are being pumped out |
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is cardiac muscle less permeable to K+ ions once an action potential begins?
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yes
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cardiac muscle less permeable to K+ ions once an action potential begins, what does this mean?
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K+ flows out VERY slowly, which increaes time that some positive ions stay inside the membrane
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name venous path of blood through the heart
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in through superior/inferior vena cava, into right atrium, right ventricle, pulmonary arteries
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name arterial flow of blood through the heart
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into heart from pulmonary veins, left atrium, left ventricle, aorta, brachiocephalic/LCC/Lsubclavian
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name the parts of the conduction system of the heart
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SA node, internodal fibers, AV node, AV bundle, left/right bundle branch, purkinje fibers
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where is the SA node located?
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wall of right atria near where the 2 vena cava enter
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where is the AV node located?
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posteroinferior region of the interatrial septum near the opening of the coronary sinus,
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what is the fucntion of the AV bundle?
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transmits electrical impulses from AV node (located between atria and ventricles) to point of the apex of the fascicular branches.
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where is the AV bundle located?
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(located between the atria and the ventricles)
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where is SA node located?
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right atrium of the heart,
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what is the function of the SA node?
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pacemaker
impulse-generating tissue, generator of sinus rhythm |
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where are the purkinje fibers located?
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inner ventricular walls of the heart, just beneath the endocardium.
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what is the function of the purkinje fibers?
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conduct an electrical stimulus or impulse that enables the heart to contract in a coordinated fashion.
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what is the P wave on an EKG?
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first wave of depolarization - from SA node to AV node
2 atria contract pumping blood |
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what is the QRS complex on an EKG?
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depolarization of the right and left ventricles
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what is a T wave on an EKG?
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repolarization (or recovery) of the ventricles
ventricular diastole |
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what is systole?
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when atria contract
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what is diastole?
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atria relax
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through what valve does blood enter the pulmonary trunk?
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through the pul. semi-lunar valve
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through what value does blood enter the ascending aorta?
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aortic semi-lunar
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what generates the "lub" heart sound?
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when the 2 AV valves close
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what causes the "dub" heart sound?
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closing of 2 semi-lunar valves
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what is the ability of the SA node to send signals even without vagus input?
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inherent rhymicity
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sinus tachycardia has a rate of what?
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>100 bpm
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what are the major causes of sinus tach?
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NS stim, increase in body temp, other abnormal conditions
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what rate does sinus bradycardia have?
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<60 bpm
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what are the major causes of sinus bradycardia?
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well conditioned athlete, decreased body temp, vagal stim of heart
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what occurs when the SA node send out irregular impulses?
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sinus arrhythmia
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what are sinus arrhythmias caused by?
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"circulatory reflexes" that change that strength of sympathetic/&or parasymp signals to SA node
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can a sinus arrhythmia occur during inspiration/expiration?
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yes
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what happens when an SA node signal is prevented from reaching the atrium?
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SA block
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what happens if an SA node signal does not reach the atria?
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the atris do not contract, no P wave
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why can a QRS and Twave still occur even if an SA node signal does not reach the atria?
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b/c the AV node can initiate a new stimulus so that the QRS and t waves still show up
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name the 4 major situation that cause the signal from the AV bundle to be blocked
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1) iscehmia of Av node
2) extreme vagal stimulation of heart 3) AV node inflammation 4)compressed AV bundles due to scar/ calcification |
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what is a situation in which the heart (or part) beats too soon?
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premature contraction
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most common causes of premature contraction?
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ischemia, calcified plaques in the heart, toxic irritation
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does the p wave occur too soon in a premature atrial contraction?
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yes
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since the p wave occurs too soon in a premature atrial contraction, what happens to the PR interval?
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shortened
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what happens to the next cardiac cycle after a premature contraction?
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if normal = longer interval b/w premature atrial contraction and next atrial contraction - compensatory pause
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what can cause a premature atrial contraction?
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lack of sleep, alchoho, drugs, smoking, drinking too much coffee
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what is a p wave missing in an AV nodal or bundle premature contraction>
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its superimposed on the QRS-T waves
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are AV nodal, AV bundle premature contactions caused by the same things as premature atrial contractions?
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yes
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what EKG finding is characteristic of a premature ventricular contraction?
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abnormally large QRS-T complex
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what are the causes of premature ventricular contractions?
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lack of sleep, smoking, coffee, emotional states
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are patients with persisent premature ventricular contractions more likely to develop ventricular fibrillations?
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yes
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what does "paroxysmal" mean?
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sudden onset of symptom
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are AV nodal, AV bundle premature contactions caused by the same things as premature atrial contractions?
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yes
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what EKG finding is characteristic of a premature ventricular contraction?
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abnormally large QRS-T complex
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what are the causes of premature ventricular contractions?
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lack of sleep, smoking, coffee, emotional states
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are patients with persisent premature ventricular contractions more likely to develop ventricular fibrillations?
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yes
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what does "paroxysmal" mean?
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sudden onset of symptom
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how long can paroxysms last?
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few seconds to days
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is an abnormal AV node rhythm a possible cause for an atrial paroxysmal tachycardia?
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yes
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why is ventricular paroxysmal tachycardia a serious condition?
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normally does not occur unless there has been ventricular ischemia, often occurs prior to v. fib
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what is the most serious cardiac arrhythmia?
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ventricular fibrillation
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how quick can a pt with vent. fib die if it is not stopped?
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2-3 MIN
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what does v. fib occur from?
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berserk cardiac impulses
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what happens to the resulting rhythms in v fib>
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they feedback on themsevles, which re-stimulates the arrhythmia, leads to complete cardiac cycle never occuring
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what can cause a fib?
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lesion of tricuspid and mitral valves - cause atria to swell b/c they cant empty properly
v. failure |
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will a fibrillating atrium pump blood to the ventricles?
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no
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does blood still get to the ventricles if the atria are fibrillating?
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passively and not efficiently
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what happens to the ventricles when the atria are not pumping and they are getting passively filled?
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their pumping also decreases
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are there commonly p waves in a fib?
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no
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what causes atrial flutter?
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atrial circus movemebts
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this law refers to an intrinsic regulation of heart pumping?
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Starlings law
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does how much blood that is pumped out of the heart depend of how much venous blookd returns to the heart?
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yes - as a general rule
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according to Straling's law, can the heart intrinsically change its rate of pumping depending on the volume of venous return?
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yes
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What law is this...direct relationship between amts of blood entering the heart and the force with which the heart contracts?
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Starlings law
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according to starlings law, if venous return to the heart increases, then cardiac systole decreases to clear extra blood?
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FALSE - increases
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does the sympathertic system innervate the myocardium?
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yes
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does the sympathertic system cause an increase of decrease in heart rate and systolic force and also increase/decrease C.O?
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increases all
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what happens to the heart if sympathethetic innervation is reduced?
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HR also reduced
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what is the effect of norepi that the sympathetics release?
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increases myocardial permeability to Na+, Ca++ - less of a stimulus is needed to increase the rate of systole
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where does the vagus mainly go?
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SA and AV nodes, some to atrial myocardium, NONE to ventricular myocardia
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what is the vagus's main effect on the heart?
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RATE of contractions, limited effect on force of contraction
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AcH from the vagus acts to reduce heart rate by?
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inhibitiing SA node, decreasing AV node excitability
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how does ACh work on the heart?
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increases the SA and SV nodes K+ outflow, makes inside of nodes more negative = hyperpolarization
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what is the effect of K+ and Ca++ ions in the extracellular fluids of the heart if K+ is too high?
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heart dilates and becomes flaccid,
b/c extra K+ lowers the resting membrane potential, which lowers action potential strength, which weakens heart contractions |
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what is the effect of K+ and Ca++ ions in the extracellular fluids of the heart if Ca++ is too high?
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heart goes into spastic contractions
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what is "any vessel that carries blood away from the heart"?
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artery
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why can arteries be under higher pressure than veins?
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bc they have muscular walls
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do arteries carry oxygenated or deoxy blood?
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oxygenated
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what are the ONLY 2 arteries that carry deoxygenated blood?
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pulmonary arteries
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what are the smallest arteries before blood enters a capillary?
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arterioles
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what structure regulates blood flow into capillary beds?
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aertioles
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T/F aretioles cannot vasoconstrict or vasodilate because they do not have muscular walls
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false - they can contrict to the point of being closed, can vasodilate to point of increasing blood flow to a tissue x7
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what are the places where substance can be exchanged b/w blood and interstitial fluids?
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capillaries - capillary beds
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what things can be exchanged in the capillary beds?
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nutrients, respiratory gases, hormones, electrolytes, various fluids
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what quality of capillaries allows exchange to occur?
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walls are very thin and very permeable
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what are "tiny vessles that drain a capillary bed after exchanges of material have occurred"? also 1st vessel in venous system
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venules
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what is any vessel that carries blood TOWARD the heart?
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veins
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what structure acts as a blood reservoir?
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veins -
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are veins more or less muscular than artieries?
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less - allows blood to pool
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can veins vasodilate and constrict?
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yes - helps their ability to act as blood reservoirs
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how much blood is carried in systemic ciruclation?
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84%
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where is most of the blood in the systemic circulation?
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systemic venous system (reservoir effect) 64% - know this #
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where is the rest of the blood in the systemic circulation?
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20% systemic arterial system - know this #
, 7% in arterioles/capillaries |
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where is the blood that is not in the systemic circulation?
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7% heart, 9% pulmonary vessles,
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there are 3 basic principles that underlie all circulation functions...explain what it means that "a tissues needs determines rate of blood flow to that tissue"
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if a certain tissue uses lots of nutrients, then blood flow will be increased to that tissue - tissues have the ability to self regulate using local control of vasoconstriction/vasodilation
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there are 3 basic principles that underlie all circulation functions...explain what it means that total control of all "local tissue blood flows" controls CO
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heart can respond to tissue demands, heart responds to TOTAL vol of venous rtn to the heart by altering its pumping rate and/or force of contraction - ANS may assist in this by increasing stim to SA node
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there are 3 basic principles that underlie all circulation functions...explain what it means that arterial pressure (BP) is controlled independently of local blood flow control &/or CO
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if BP falls <100 mmHG, then within seconds a NS response occurs to increase BP
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what are the NS responses that occur to quickly increase blood pressure?
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vasoconstricion of arterioles (increases BP by increasing blood volume in the larger arteries) , cardiac systole (becomes more powerful), venous reservoirs vasoconstrict (to pump more blood to the heart), hormonal influences
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T/F the realtionship b/w the "corss-section (xs) area" of blood vessels and the speed with which blood flows is important
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true
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the venous system take up for _________ X.S area than does the arterial system
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MORE
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do capillaries take up a larger or smaller XS area than the total XS area of the veins and arteries combines?
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greater X6
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what is the force that blood exerts on blood vessles>
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blood pressure
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where is the highest pressure in the systemic circulation?
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aorta, large arteries
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where is the lowest pressure in the systemic circulation?
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vena cava - zero
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where is the highest pressure in the pulmonary circulation?
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pulmonary arteries
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where is the lowest pressure in the pulmonary circulation?
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pulmonary veins
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T/F arterial BP is lowest at level of the heart
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false - highest
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t/f from heart to capillaries there is a steady decline in BP
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true
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t/f avgerage BP in venous tree is significantly higher than arterial tree
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false- lower
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t/f BP drops to almost 0 mmHG in vena cava
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true
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does what is going on in the right atrium affect the venous return to the heart?
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yes
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what is "the amt of blood that flows past a designated point in some specific period of time"
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blood flow
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what does it mean to say that a pts CO = 5000 ml/min?
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5000 ml/min is the amt of blood that flows from the heart to the ascending aorta
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what 2 factors control blood flow through a vessel?
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pressure difference, velocity of blood flow
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what is the difference b/w the pressures at the 2 ends of vessel?
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pressure difference, aka pressure gradient - this difference causes blood to flow
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how can veolcity of blood flow be calcaulted?
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velocoty = flow/cross sectional area
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name the order of flow velocites from the aorta
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aorta, arterioles, small veins, capillaries
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what is anything that opposes blood flow in the vessels?
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vascular resistance
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what is vascular resistance due to in healthy vessles?
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friction b/w the vessel walls and the moving blood
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what is vascular resistance due to in abnormal vessles?
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damage to endometrium, blood clots
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what is the usual way to calcuate "vacular resistance"?
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select 2 pts in a vessel and then measure blood flow and pressure differences b/w those 2 points
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what is meant by total peripheral resistance?
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pressure difference bw the systemic and pulmonary systems
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what is cardiac output?
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amt of blood leaving the heart in some unit of time
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what is the formula for CO?
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HR X SV
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what is the law bases on the relationship b/w pressure differences at the 2 ends of a vessle and the resulting vascular resistance to blood flow?
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Ohms law
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does vascular diameter affect resistance to blood?
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yes - smaller vessle offer more resistance than larger ones
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are differences in blood pressure in various vessles in the body partly due to the size of the vessles?
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yes
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what law is a way to calculate the blood flow in different sized vessles, or in vessles whos diamter is changing?
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Poiseille's law
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what law says that the rate of blood flow will be higher in larger vessels than in smaller vessels?
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Poiseille's law
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why do larger vessles have a greater rate of blood flow?
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large diameter vessels have a larger stream diameter, then the center of that stream will NOT by touching the endometrium and will NOT affect resistance to flow as much as the blood that is actually touching the endometrium
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can hematocit affect blood flow?
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yes
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what happens to blood flow as viscocity increases?
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blood flow decreases
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does the bloods contents affect the viscosity?
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yes
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what is the effect of BP on blood flow?
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increase in BP does NOT cause a proportional increase in blood flow, effect on BP is disproportinally large
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why is the effect of increasing blood pressure greater than expected?
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b/c as BP increases:
provides more force to push blood through a vessel, causes the vessel diameter to expand, which lowers vascular resistance |
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what refers to the increase a vessle's blood volume as blood pressure increases?
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vascular distensibilty
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are arteries less distensbile than veins?
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yes
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does increased blood volume cause arteries to distend?
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yes
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what is the exception to arteries being less distensible than veins?
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pulmonary arteries - much more distensible than systemic veins
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what is the formula for vascular distensibilty?
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VD = increase in vol/(increase in pressure) (original vol)
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T/F knowing vascular compliance of blood vessles is more important than knowing blood vessel distensibilty
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true
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is it possible for a very distensible vessel to have very little volume? which means that it also has less compliance that does a much less distensible vessel?
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yes is possible - why the vascular compliance of veins is 24x that of arteries
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t/f vascular distensibiltiy and vascular compliance does tells us that any particular blood volume change will cause a larger increase in arterial BO than it does venous BP
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true
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t/f when veins become constricted, a lot of blood is pumped to the heart, which will result in larger CO
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true
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why can up to 1/2 a litter of blood can be transfused into a pt in a few minutes without any major increase in pts BP?
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to alter venous pressure by just 3-5 mmHG would require hundres of ml of fluid
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t/f sympathetic stimulation of not a major physiological mechanism used to increase venous blood return to the heart, which will result in an increase in force &/or frequency of heart pumping
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false
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t/f sympathethic control of vascular complanice is very important in a situation such as hemorrhage
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true
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what is a surge of blood that fills the arteries when the heart contracts?
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pressure pulsation
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how can pulse pressure be calculated?
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pulse pressure = (systolic pressure)-diastolic pressure
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what is a normal pulse pressure?
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40mmHg
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what are the 2 main factors that affect pulse pressure?
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hearts stroke volume output, capacitiance of the arterial tree
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does increases stroke volume result in increases cardiac output? would this increase systolic pressure or diastolic pressure?
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yes
systolic pressure causes increased pulse pressure |
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what happens as arterial complaince decreases?
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stoke volume pressure increases
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what happens to pulse pressure in arteriosclerosis?
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vessles become less compliant, increases blood pressure, resulting increased pulse pressure
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what is a decrease in the size of any canal or opening?
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stenosis
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what is it called when the diameter of arotic semi-lunar valves decrease?
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aortic stenosis
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does aortic stenosis cause more or less blood to flow through the valve? and what hapens to the pulse pressure?
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less
decreases |
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what is the ductus arteriosus?
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fetal connection b/w the pulmonary trunk and descending thoracic aorta
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where does blood throw the ductus arteriosus?
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from pulmonary trunk into descendng aorta,bypassing the lungs
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do the fact that blood bypasses the lungs in the fetus cause a increase/decrease in diastolic pressure b/w heart beats?
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decrease
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what happens in arotic regurg?
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aortic semi-lunar valve is missing or is present but doesnt close properly
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what is the result of aortic regurg?
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when left ventricle goes into diastole, blood flows back into it from ascending aorta
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can the pressure in the aorta fall to zero during diastole in aortic regurg?
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yes in severe cases
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is there a lack of an incisura in aortic regurg?
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yes
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how much effect does gravity have on blood pressure in major arteries?
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not much, because they are so muscular
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does gravity have an effect on smaller arteries and capillaries?
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yes
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what happens to arterial pressure as you get farther away from the heart?
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gets lower
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name fucntions of veins...
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return blood to heart, blood reservoirs d/t distensibility, move blood by action of venous pump, help regulate cardiac output
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what is the central venous prssure?
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central venous pressure
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does all venous blood enter the rt atrium through the superior and inferior vena cava?
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yes
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what is the normal central venous pressure?
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0 mmHg
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in the distended state, do large veins have resistance? how important are they in pumping blood to the heart?
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bascially none, unimportant
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do surroudning structures affect the resistance of veins?
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yes they can cause compression points that can cause the pressure in small peripheral veins to be higher than the central venous pressure
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what are the conseqences to peripheral pressure if central venous pressure increases above 0mmHg?
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venous rtn to rt atrium is decreased, Blood backs up in brain, distention of veins, final = increased peripheral venous pressure
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if abdominal pressure rises, why must venous leg pressure also rise?
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abdominal vein pressure rises, so leg veins must increase their pressure to pump blood up the adbominal veins
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what can cause compression of abdominal veins?
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pregnancy, buildup of abdominal fluids, adb tumors
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what is the effect of gravity on venous pressure?
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blood weight pressure run from -10 mmhg in the head to 90+ mmHg in the feet
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what is the pressure in the neck veins?
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0mmHg b/c they are at a compression point and gravity keeps them closed
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which has one-way valves..arteries or veins?
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veins
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what do one way valves in veins allow?
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movement of blood only towards the heart
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what does the venous pump entail?
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action of one way vein valves coupled with skeletal msucle contractions
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what happens during the venous pump?
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muscle contraction compresses veins, these veins push blood through venous valves toward the heart, when muscles relax, one-way valves cloase and prevent back flow
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will the venous pump work in a stationary, standing patient?
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no the pump doesnt work and venous pressure can rise tp 90+ mmHg , legs can swell due to pooling of blood in leg veins
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what are variose veins?
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veins whose valves are not working properly
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what are the nurtients that need to get to and from tissues in blood?
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o2, glucose, amino acids, FAs, hormones, removal of Co2 and H+, nitrogen compunds
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can tissues control their own local blood flow depending on their metabolic needs?
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yes
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do tissues control their blood supply at a minimal level required to obtain needed nurtients?
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yes
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t/f as metabolism increases in a particular tissue, blood flow to that tissue will also increase
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true
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why doesnt the circulation supply all tissues with a large blood flow all the time?
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would require heart to pump more blood than it is capable of pumping, waste of energy
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what is acute control of blood flow?
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rapid changes (secs-min) in the diameter of local arterioles and small vessels
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give examples of acute control of blood flow
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increased metabolism, increased blood flow
as tissue nutrients decrease, blood flow to that tissue will increase |
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what is reactive hyperemia?
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blood flow has stopped, vessel is unblocked, flow of blood will increase dramitically above normal
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what is active hyperemia?
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tissue very active (exercise) blood flow to that tissue increases , can increase by 20x normal
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what is the name for when "blood o2 levels decrease, blood flow to tissues"//its a theory
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oxygen lack theory for local blood flow regulation - also called nutrient lack theory
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