Cardio I Exam

Question 1

What causes the first heart sound (S1)?

Answer 1

Closure of the AV valves

Question 2

What causes the second heart sound (S2)?

Answer 2

Closure of the semilunar valves

Question 3

Where are B1 receptors found?

Answer 3

Mostly in the heart, specifically the conduction system (AV and SA nodes, Purkinje fibers) and the atrial and ventricular myocardium

Question 4

What happens when B1 receptors of the heart are stimulated?

Answer 4

Stimulation increases heart rate (chronotropy) and force of myocardial contraction (inotropy)

Question 5

Where are B2 receptors found?

Answer 5

Heart and vascular smooth muscle

Question 6

What happens when B2 receptors are stimulated?

Answer 6

Stimulation increases heart rate and force of myocardial contraction. Also results in vasodilation because of the location of the receptors on vascular smooth muscle

Question 7

Where are B3 receptors found?

Answer 7

In the myocardium and coronary vessels

Question 8

What happens when B3 receptors are stimulated?

Answer 8

Stimulation opposes the effects of B1 and B2 receptor stimulation and decreases myocardial contractility (negative inotropic effect); may provide a “safety mechanism” to prevent overstimulation

Question 9

Where are A1 receptors located?

Answer 9

Postsynaptic neurons in the systemic and coronary arteries

Question 10

What happens when A1 receptors are stimulated?

Answer 10

Smooth muscle contraction and thus vasoconstriction

Question 11

Where are A2 receptors located?

Answer 11

On the sympathetic ganglia and nerve terminals

Question 12

What happens when A2 receptors are stimulated?

Answer 12

The effect of NE on these receptors is to inhibit release of more NE, which promotes vasodilation, thus providing another safety mechanism to prevent excess blood pressure elevation

Question 13

Which vessels empty into the right atrium?

Answer 13

SVC, IVC, and coronary sinus

Question 14

Which vessels empty into the left atrium?

Answer 14

Pulmonary veins

Question 15

What is myocardial oxygen consumption (MVO2)?

Answer 15

Cardiac work, i.e., how much energy is used

Question 16

What 3 major factors determine MVO2?

Answer 16

1. Amount of wall stress during systole - estimated by measuring systolic BP
2. Duration of systolic wall tension - measured indirectly by HR
3. Contractile state of the myocardium - not measured clinically

Question 17

Increased energy needs can be met ONLY by increasing _____________?

Answer 17

Coronary blood flow

Question 18

What is the percentage of blood pumped out of the ventricles compared to the amount of blood in the ventricles at the end of diastole called?

Answer 18

Ejection fraction

Question 19

What 4 factors affect cardiac output directly?

Answer 19

Preload, afterload, myocardial contractility, and heart rate

Question 20

Volume inside the ventricle at the end of diastole is called

Answer 20

Preload

Question 21

What is measured to estimate preload?

Answer 21

Central venous pressure (CVP) on the right side. Pulmonary artery wedge pressure on the left side.

Question 22

What is the resistance to ejection of blood from the left ventricle?

Answer 22

Left ventricular afterload

Question 23

An index of afterload is ___________

Answer 23

aortic systolic pressure