Med. Physiology CARLA 8 – Flashcards
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Keeping blood in the different chambers of the heart from mixing is a function of the ___.
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septum
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When blood leaves the heart, it first enters ___.
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arteries
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Which of the following is NOT a component of the pulmonary circuit?
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Venae cava
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Blood supply to the heart comes from ___.
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coronary arteries
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Identify the structure that separates the thoracic cavity from the abdominal cavity.
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diaphragm
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Which of the following chambers has the thickest musculature?
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left ventricle
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Which of the following statements is true regarding the valves of the heart?
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(all of these) The aortic valve is a semilunar valve, all four valves open and close passively in response to pressure gradients, the left AV valve is also called the mitral vale
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Chordae tendinae are strands of connective tissue extending from ___ to ___.
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AV valves : papillary muscle
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Closure of the atrioventricular valve occurs when ___.
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pressure inside the ventricle is greater than pressure inside the atrium
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Whereas the contractile activity of skeletal muscle is called ___, that of cardiac muscle is ___ because the contraction originates within the musculature itself.
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neurogenic : myogenic
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What are the two major regions of the heart containing pacemaker cells?
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sinoatrial node and atrioventricular node
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Which of the following will occur within the systemic capillary beds?
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both net flux of oxygen out of the capillaries and net flux of carbon dioxide into the capillaries
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The ___ carries deoxygenated blood to the lungs?
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pulmonary artery
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The relative color, depth of redness, of blood is a direct indication of the amount of ___ bound to hemoglobin.
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oxygen
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The tern autorhythmicity refers to the heart's ability to ____.
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generate its own contractile cycle
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Which of the following statements is true?
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both Intercalated disks contain gap junctions and Intercalated disks contain desmosomes.
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Which of the following ion channels must be open for a cardiac pacemaker cell to depolarize to threshold for an action potential?
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both funny channels and T-type calcium channels
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___ is responsible for the repolarization of pacemaker cells.
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an increase in P(k)
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What causes the rapid depolarization phase of a contractile cell action potential?
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sodium movement into the cell
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Which of the following statements about the plateau phase of a contractile cell action potential is FALSE?
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the membrane potential remains the same as the peak of the action potential for about 200 milliseconds
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Which of the following components of the ECG represents ventricular repolarization?
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T wave
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If damage to the AV node slowed down conduction through this tissue, what would be observed on an ECG?
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a longer PR interval
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In an ECG recording, the RR interval is 0.5 seconds. What is the heart rate?
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120 beats/min
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In second degree heart block, ___.
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not every atrial contraction is followed by a ventricular contraction
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During isovolumetric ventricular relaxation, ___.
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all of these: the AV valves are closed, the semilunar valves are closed, ventricular pressure is decreasing.
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During ventricular ejection, ___.
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both the semilunar valves are open and left ventriclar pressure is greater than aortic pressure
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Which of the following is true of the ventricular filling phase of the cardiac cycle?
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ventricular pressure is less than aortic pressure
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Which of the phases of the cardiac pump cycle listed below are part of systole?
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both isovolumetric contraction and ventricular ejection
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Ejection of blood from the right ventricle will continue until ___.
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pressure in the pulmonary artery is greater than pressure in the right ventricle
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The increase in ventricular volume early in diastole reflects ___.
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the passive movement of blood through the atrium and into the ventricle
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The end-diastolic volume minus the end-systolic volume is the ___.
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stroke volume
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What causes the sounds that one hears as the heart beats?
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the turbulence created as the valves close
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The SA node is innervated by ___.
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the sympathetic and parasympathetic nervous systems
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Which of the following decreases heart rate?
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parasympathetic nervous system activity
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The binding of a catecholamine to a beta adrenergic receptor will ___.
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activate adenylate cyclase
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Which of the following decreases stroke volume?
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decrease in central venous pressure
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An artery is a blood vessel that:
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transports blood away from the heart
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Put the following events of the cardiac cycles in the correct order, starting with the ventricular filling phase: (first heart sound, P wave of ECG, ventricular pressure is greater than atrial pressure and isovolumetric relaxation).
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P wave of ECG, ventricular pressure is greater than atrial pressure, first heart sound, isovolumetric relaxation.
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Which of the following will increase the force of contraction of the ventricles?
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increasing end-diastolic volume
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Put the following structures involved in cardiac impulse conduction in the correct order: AV node, Purkinje fibers, SA node and Bundle of His
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SA node, AV node, Bundle of His and Purkinje fibers
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Why not have intercalated disks or gap junctions in skeletal muscle?
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not optomized for inter-connections because inter-connections don't allow for fine motor movements
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Which heart sound is the lub in relation to the cardiac cycle?
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x- where the AV valve closes
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What would be the direct effectors of beta-blockers on heart function? some amount of adrenaline
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It would contract less strongly
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Why is blood pressure highest in the arteries and lower in arterioles etc?
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because total cross section
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What would be the effect in blood vessels if they were NOT compliant (elastic)?
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vessel pressure would be too high
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What would most immediately happen in the lymphatic system became blocked?
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Interstitial space (volume) would expand
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How would protein starvation most directly lead to edema?
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by decreasing in pie-cap
