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### 41 Cards in this Set

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 What is the relationship between the area of a blood vessel and the resting velocity of the blood that flows through it? inversely proportional What does the inversely proportionate relationship of vessel size and velocity say about capillaries? blood moves very quickly through capillaries What are the 3 basic underlying principles of the circulatory system? 1. Rate of blood flow is controlled by the individual needs of each tissue (microvessels monitor O2, CO2 and nutrients), 2. Cardiac output is controlled by the sum of all local tissue flows (venous return increases output), 3. Arterial pressure is controlled independently of local blood flow and cardiac output (nervous systen in response to arterial pressure: a) increase force of heart pumping, b) contraction of large venous reservoirs to send more blood to the heart, c) constriction of artriole to divert more blood to the main arteries and raising blood pressure. State Ohm's Law with respect to Flow, pressure and resistance. F=(P1-P2)/R=∆P/R What does Ohm's law say about the relationship between flow and the difference in pressure? it is proportional to the pressure difference What does Ohm's law say about the relationship between flow and the resistance? it is inversely proportional Chapter 16 How is resistance affected by increased pressure (vessel distensibility)? What effect will this have on flow? increased pressure -> vessel dialation -> decreased resistance -> increased flow Besides its role in adjusting blood flow, what can be said about vessel distensibility's role? it plays a role in blood storage (resevoir) What fraction of sinuses in the heart are cornary? 3-Feb All valves are tricuspid except which? the mitral valve which is a bicuspid valve What of the mitral vavle leaflet is larger? the Anterior leaflet, nearest the Aorta What are the 3 functions of the pericardium? (on is a role in pathology) 1. Limits acute chamber dialation, 2. Controls ventricular interaction, 3. In pathology it often defines pathology From superior to inferior, what are the branches of the right coronary artery, and what do they serve? SA node artery (right atrium), Acute marginal arteries ( right ventricle), Posterior left ventricular branches (right ventricle), Posterior descending artery Vendricle), AV node artery(right atrium) What are the branches of the left coronary artery and what do they serve? Left anterior descending (left ventricle), left circumflex artery (left ventricle), Septal branches (left ventricle), Diagonols (left ventricle), obtuse marginal arteries (left ventricle), left atrial circumflex artery (left atrium) What disease is associated with the sinus node artery? sinus arrest What disease is associated with AV node artery? Heart block What two disease are associated with PDA (Posterior descending artery)? Septum and posteromedial papillary muscles What disease is associated with posterior left ventricular branches? posterior wall What disease is associated with acute marginal arteries? Right ventricle infection Which right coronary artery is most commonly associated with disease? acute marginal arteries Which two diseases are associated with Left anterior descending artery? Anteroseptal infarct, cardiogenic shock Which three diseases are associated with the circumflex artery? Posterior/inferior infection, Anteriolateral papilary muscle (often jointly with LAD) Chapter 10 Do fast sodium channels cause the action potential in the sinus node? Why? No, because the resting potential is about -55, so fast sodium channels would have already been inactivated at this voltage… thus they are blocked What causes the action potential in sinus nodal fibers? (Hint: comparet the AP curves of the sinus nodal fibers with the ventricle AP.) slow Na-Ca channels.. Which means that the atrial nodal potential is slower to start… compare the AP curves Which ionic flux causes the rise in membrane potential in sinus nodal tissue toward threshold? Why does this happen? Na, because of high extracelluar concentration and a moderate number of Na channels already being open. In sinus nodal tissue, at what membrane potential is the threshold for AP? Which channels open at this threshold? minus 40mV, Slow Na/Ca channels Which "leaky" ionic flow causes the self-excitation of sinus nodal fibers? Na/Ca Why don't sinus nodal fibers remain depolarized? Na/Ca channels close shortly after opening, at the same time K+ channels are opening (they stay open longer) and as such they are lowering the membrane potential. What complete the cycle for sinus nodal fibers? K+ channels close, while Na/Ca channels begin to leak once more What is the conduction pathway in the heart that allows the atria to contract followed .6 sec later by ventricle contraction? Sinus nodal fibers are self-excited -> transmission to atrial muscles and conduction to the A-V node (Delayed conduction) -> to bundle of HIS (fast conducting) -> purkinje system -> ventricle Can conduction travel back from the ventricle to the atria? no Which has the fastest intrinsic HR, SA node, A-V node or purkinje fibers? SA node… this is why it's the pacemaker of the heart. What is an ectopic pacemaker? when the HR is set by a part of the heart other than the SA node, e.g., A-V node or purkinje What is the most common pacemaker in an ectopic pacermaker when there is SA node blockage? A-V node What occurs when there is a A-V blockage? What is this called? there is a delay purkinje pacemaker HR set for the ventricles… the delay can be as much as 5-20 seconds later… causing fainting or death. Stokes-Adams syndrome What branch of the ANS controls the rate of the SA-node? And which NT? parasympathetic, ACh What clinical effects does ACh have on the SA-node? What is the chemical effect does ACh have on the cells membrane? a) slow the HR and it decreases the excitability of SA-junctional fibers and thereby slow conduction to the ventricles. b) it increases K+ permeability causing hyperpolarization (below -55mV), making the tissues less excitable What 3 effects does the sympathetic NS have on cardiac rhythm and conduction? 1) It increase the SA node discharge and 2)raises the level of excitability in all parts of the heart. 3) increases the force of contraction. What does the sympathetic NS release to the heart? What is thought to be the mechanism by which this NS works? Norepinephrine, increase Na/Ca permeability