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38 Cards in this Set
- Front
- Back
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What is the physiology of the heart? |
1. Heart is enclosed in a fibrous sac, pericardium 2. Membrane on the outside, epicardium -Between the two cardium has watery fluid that serves as a lubricant as the heart moves within the sac 3. Myocardium is cardiac muscle cells of th ehwalls 4. Endothelial cells that lies the inner surface of the cardiac and blood vessel |
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What is the cardiac anatomy of the aheart |
1. Vena cave pumping blood back to the right atrium 2. tricuspid valve from Right atrium to right ventricle ( papillary muscle prevents backflow) 3. blood goes through the lung to the veins t ogbo back to the left atrium (biscupid valve) 4. Enters the left ventricle to aorta and thorug the body 5. Interventricular septum separates the two walls |
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What are cardiac muscle |
Striated as the results of thick myosin and thin actin filaments -shorter with more branchign Uses gap junctions by intercalated disk for communications |
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What is the gap juntion purpose? |
Allow ap to sprad from one cell to another So one exictation leads to all |
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What are pacemaker cells |
spotntaneous contractions at the SA nodes 1% are pacemaker cells |
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What is the contracticle pattern of the heart |
Sinoatrial node depolarizes that leads to tehe atrium to depolarize eventially goes down the bundle of his to the purkinje fiber to depolraize the ventricle |
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What are the nodes |
SA node : pacemaker AV noddes at the base of the right atrium that is progprogates slowly to give the atria a chance to contract |
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What is the bundle of his and purkinje fiber |
Bundle of his is fiber down the septume to connect to the purkinje to distribute the impulse throguh ventricles
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What is the resting membrane potential |
More permeable to potassium than sodium probably due to size -90mV +20Mv for threshold sodium has equilibrium potential of 60 mV |
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What is the ventricular action potential |
1. Begins with depolarization whre sodium channels open to allow potassium to flow in and potassium channel closes to prevent positive charge from leaving 2. Partial repolarization where it plateuas and sodium channel closes and fast pottasium channels open to allow some pottasim to leave 3. Plateau face wher calcium channels opens ( L) where it steadily opens for awhile calcium goes in 4. Repolarization here calcium channels close and slow pottasium opens 5 resting |
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What contribute to the prolong plateau depolarrization? |
Slow and prolong opening of voltaged calcium channels and plus closure of pottasium channels Allow the slow contraction phase to pump the blood out The dip afterwards |
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What contribues to the repolarizatio phase |
opening of potassium channels |
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What contributes to the rapid depolrization |
sodium channel opens |
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What is the excitation contraction coupling pathway?cardiac |
1. Excitation by a neighbor cell 2. Calcium flows in and interacts with the ryanodine receptor channel (RyR) 3. This leads to a local release of calcium 4. Collectivetly the ions causes a calcium signals 5. Calcium binds to troponin (calmodulin for smooth muscle) to intiiate contraction 6. Relaxation occurs when calcium is pumped back in for storage 7. Calcium leaves by exchanging sodium 8 This creates a gradient along iwth the sodium pottasium atpase |
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What is the AP for a pacemaker cell? |
1. Sodium channels leaking through the funny channel + calcium move in through T channels promotes graded depolarization 2. Rapid opening of voltaged gated channel is responsible fore the rapid depolariation phase. Calcium opening ( L ) 3. The repolarization is caused by potassium channels opening and closing of calcium channels |
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What is the biggest difference between the two cardiac cell AP? |
Autorhymethic cell does not have a resting potentia lbecause of the sodium channel leackage of the funny channel and t channels calcium that moves calciums in |
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How do symapthetic signal affect the heart? |
Increase sodium and calcium influx to the pacemaker cells by allow the cells to reach threshold faster |
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How do parasympathetic signal affect the heart |
Increase potassium movement otu of the pacemaker cells allow it to reach threshodl less freqeuently |
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difference between smooth/cardiac |
Cellular both uninucleated Smoth = spindle, cardiac = branch Cal = smooth cardaic =trop no tetanus Cardiac = t tubules |
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What is chronotrophy? |
Heart rate |
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What affects chronotrophy? |
Increase Beta-1 receptors ( Sympathetior) A1 receptors contribute by NE and Epi Decrease M2 receptor activation (PS) |
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What is inotrophy |
Heart contraction |
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What affects inotrophy |
B1 activation M2 decreases it |
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What is domotrophy? |
Conduction velocity Decr4eas with m2 receptor activation AV conduction velociltiy affected primarily Symp increase conduction PS decrease the rate of excitation |
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What is mechanism of inotrophy? |
1. increase calcium influx during AP 2. Increas calcium release from Sarco 3. Sensitizing troponin C to calcium |
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What is acetylcholine |
Agonist for m2 receptor that located in atria that results in reduction of cAMP by gI protein 1. Increase pottasium channel opening 2. Decrease opening of calcium channels 3. hypoerlation target pacemaker |
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Wahat is methacholni |
same as acetylcholnie but resistance to achE |
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What is TMA |
nicotinic receptor at the preganligonic syanpase and enhances release of AcG at the post ganglionic synpase Results in reduction of contraction Partial agonist m2 receptor |
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What is physostigmine? |
AChE inhibtiro enhances acH but can have a small decrease in cardiac output
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What is atropine? |
comeptiive inhibitor of cholinergic muscarinci receptor
Restore rate and force of contraction to control elvels |
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What is epinephrine? |
Agonist of A and beta adrenergic receptor 1. Increased opening of T-Type calcium channels 2. Increase production of cAMP 3. Phorpshoylat pka by increasing calciu mchannels ( beta activation) enhances force nad rate adn affect cardiac pcaemaker |
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What is NE |
same as epniephrine btu less potent |
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What is isoprotrenol |
same affect as N and NE. hgiher affinity for B than a |
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What is propranolol |
competitve antagonist fore the beta receptor and has a larger affect on iso protrenol
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What is phenoxybenzamine |
Irreversible noncomeptive antagonist of NE atalpha receptor less effect on isoprotrenol |
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What is verapamil |
Blocks L type calcum channels which prolongs the refractory phase
slow doesn ventricular rate Depress atrial fibver decreasing amplitude, velocity of depolarization and conductiona velcoity |
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What is good about the prolong phase of cardiac muscle |
Prevents tentanus and allow ventricles to fill before pumping |
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What is ectopic pacemaker |
too mcuh ventricular tissue that leads to arrhymia Epi eals with ectopic pacemaker |
