Exam 7: The Peripheral Nervous System: Efferent Division

An increase in parasympathetic activity ____________________ the rate of depolarization of the SA node.

Why can't tetany of the heart occur under normal conditions?

Increased EDV results in decreased stroke volume.

Match the valve abnormalities, labelled a. and b., with the descriptions. (Options may be used more than once or not at all.) a.valvular stenosis b.valvular insufficiency -valve does not close completely

With 2:1 rhythm, the atrial rate is very rapid and the ventricular rate is normal or above normal, whereas with 2:1 block, the atrial rate is normal but the ventricular rate is below normal

An increase in cardiac sympathetic activity ____________________ the stroke volume.

Contraction of the spirally arranged cardiac muscle fibres produces a wringing effect for efficient pumping.

The second heart sound occurs when the semilunar valves close. What does this mark?

Match the term, labelled a. through g., with their correct characteristic. a.gap junction b.HDL c.functional syncytium d.heart valve e.pericardial sac f.LDL g.adenosine -prevents backflow of blood

Match the terms, labelled a. through f., with the descriptions. (Options may be used more than once or not at all.) a.stroke volume b.end-diastolic volume c.cardiac output d.heart rate e.end-systolic volume f.sympathetic activity -The two main determinants of cardiac output are stroke volume and _____.

Match the factor involved in the initiation and spread of cardiac excitation, labelled d. with the description. (Options may be used more than once or not at all.)a. through a.SA node b.AV node c.bundle of His and Purkinje system d.gap junction -allows the impulse to spread from cell to cell

Match the terms, labelled a. through f., with the descriptions. (Options may be used more than once or not at all.) a.stroke volume b.end-diastolic volume c.cardiac output d.heart rate e.end-systolic volume f.sympathetic activity -The stroke volume may be calculated by end-diastolic volume minus _____.

Match the anatomical structures, labelled e., with the heart characteristics. (Options may be used more than once or not at all.)a. through a.tricuspid valve b.myocardium c.aortic semilunar valve d.AV node e.sinoatrial node -its closing partially creates the heart sound "lub"

According to the Frank-Starling law of the heart, the shorter the initial length of the cardiac muscle fibres prior to contraction, the more forceful will be the subsequent contraction because the fibres are already partially contracted.

PAF is released from the ____________________ lining of vessels.

Which of the following events occurs due to sympathetic stimulation of the heart?

Match the pressure relationships, labelled e., with the times in question. (Options may be used more than once or not at all.)a. through a.aortic pressure > ventricular pressure > atrial pressure b.ventricular pressure > aortic pressure > atrial pressure c.aortic pressure > atrial pressure > ventricular pressure d.ventricular pressure > atrial pressure > aortic pressure e.atrial pressure > ventricular pressure > aortic pressure -when the atrioventricular valve opens

Twelve complete ECG patterns are recorded from a subject over 10 seconds. If this pattern continues, what is the rate of the heartbeat in the subject?

On a normal ECG, a wave for repolarization of the atria is not recorded. Why?

The atria and the ventricles contract at the same time to ensure efficient pumping action.