Mace Cardiac Lectures 5a-5d

Question 1

T or F? When the ventricles relax, blood in the aorta flows back towards the heart, filling the coronary arteries?

Answer 1

True! At this point, during isovolumetric relaxation, both the semilunar vales and aortic valves are closed so the blood drains into the coronary arteries instead of back into the heart.

Question 2

During a normal cardiac cycle, which phase has the longest duration?

a. atrial systole
b. ventricular systole
c. quiescent period
d. valvular period

Answer 2

quiescent period

Question 3

What is the average cardiac output of a person ?

Answer 3

5-6 L/min

Question 4

Exercise will increase CO. This is because there is a ___ in HR and a ____ in stroke volume.

Answer 4

increase in HR and also an increase in SV

Question 5

Assume that the left ventricle of a child’s heart has an EDV= 90mL, ESV= 60mL, and a cardiac output of 2,400 mL/min. His SV and HR are ?

Answer 5

SV= EDV-ESV
= 90-60
SV = 30 mL

CO = (SV)(HR)
2,400 = (30)(HR)
HR = 80 bpm

Question 6

Sympathetic NS innervates AV and SA node leading to ______ in the myocardium, also affecting contractility/inotropy

Answer 6

tachycardia

Question 7

Parasympathetic NS innervates AV and SA nodes leading to ____.

Answer 7

bradycardia, surprise, surprise

Question 8

One degreee of temperature change (celsius) increases heart rate by __ beats

Answer 8

10 beats

Question 9

All of the following are heart rate stimulants except

a. epinephrine
b. caffeine, nicotine, and chocolate
c. thyroid hormone
d. potassium (and calcium ions)

Answer 9

D. potassium (and calcium ions)

Question 10

Increased venous return occurs with (LESS/MORE) ___ venous pressure or (FASTER/SLOWER)____ heart rate.

Answer 10

Increased venous return occurs with MORE venous pressure or SLOWER heart rate

Question 11

What effect does increased preload (stretch of the heart wall) have on stroke volume?

Answer 11

Stroke volume increases.

Question 12

What effect does atherosclerosis have on stroke volume?

Answer 12

Stroke volume decreases.

Question 13

What effect do inotropic agents (substances that act on contractility of the heart) have on stroke volume?

Answer 13

Stroke volume increases.

Question 14

What effect does hemorrhage or an extremely rapid heart rate have on stroke volume?

Answer 14

Stroke volume decreases.

Question 15

What effect do calcium channel blockers have on stroke volume?

Answer 15

Stroke volume decreases. Calcium channel blockers are negative inotropic agents.

Question 16

Which of the following increases stroke volume proportionally?

a. increased venous return
b. increased Ca2+ in the sarcoplasm
c. increased after load
d. A and B
e. all of the above

Answer 16

d. A and B

Question 17

Death of heart muscle from lack of oxygen is known as a myocardial infarction (MI), but what is temporary myocardial ischemia called ?

a. cardiac stenosis
b. cardiac defibrillation
c. angina pectoris
d. cardiac arrest

Answer 17

Answer: C.
explanation: cardiac stenosis is a form of fibrosis of the heart. Cardiac defibrillation is voltage used to get the heart back in rhythm and cardiac arrest is a permanent STOP in the heart beat.

Question 18

When left ventricular output exceeds right ventricular output, where will fluid accumulate?

Answer 18

In the systemic tissue

Question 19

When right ventricular output exceeds left ventricular output, where will fluid accumulate?

Answer 19

In the pulmonary tissue

Question 20

What effect will hormones such as epinephrine or thyroxine have on cardiac output?

Answer 20

These hormones increase heart rate, thus increasing cardiac output (CO= SV X HR)

Question 21

During heart surgery, your body temperature may be lowered. What effect will this have on your cardiac output?

Answer 21

Heart rate will be decreased at lower temperatures. Therefore, CO will decrease!

Question 22

What happens to cardiac output if no other compensating mechanisms occur: increased blood volume?

Answer 22

increases CO due to increase MAP linear relationship/ CO increases due to increase in stroke volume from increase preload from venous return w/ increased volume

Question 23

What happens to cardiac output if there is loss of myocardial tissue?

Answer 23

CO decreases due to loss of contractility i.e. stroke volume

Question 24

What happens to cardiac output if there is administration of verapamil?

Answer 24

Decreased CO secondary to decreased SVR

Question 25

What happens to cardiac output if there is administration of Digoxin?

Answer 25

Increased CO due to increased SV secondary to increased contractility

Question 26

What happens to cardiac output if there is an increased EDV?

Answer 26

Increased CO due to increased SV

Question 27

What happens to cardiac output with administration of a beta blocker?

Answer 27

Decreased CO secondary to decreased HR

Question 28

What happens to cardiac output in response to increased ESV?

Answer 28

Decreased CO secondary to decreased SV

Question 29

What happens to cardiac output in response to muscular contraction in the legs ?

Answer 29

Increased CO secondary to increased preload from increased venous return

Question 30

What happens to cardiac output in response to inversion of the body?

Answer 30

Increases CO due to increase SV secondary to increase venous return

Question 31

What happens to cardiac output in response to calcified aortic valve?

Answer 31

decreased CO to do increased afterload

Question 32

What happens to cardiac output in response to new prescription of HCTZ with dose too high?

Answer 32

decrease CO due to decrease SV secondary to decrease venous return i.e. volume loss

Question 33

What effect does HTN have on cardiac output?

Answer 33

CO decreases

Question 34

Which portion of an EKG represents the quiescent period?

Answer 34

T-P

Question 35

What does the P-Q segment on an EKG represent?

Answer 35

atrial contraction (delay of the AV node)

Question 36

What does the QRS segment on an EKG represent?

Answer 36

ventricle depolarization overlapping with atrial repolarization

Question 37

What does the S-T segment on an EKG represent?

Answer 37

ventricular contraction

Question 38

What does the T wave on an EKG represent?

Answer 38

ventricular repolarization

Question 39

What does increased preload do to the heart pressure volume loop?

Answer 39

P is shifted to the right, EDV shifts right, ESV is the same and SV is increased

Question 40

T or F? There is a change in height to the pressure volume loop when there is an increase in preload.

Answer 40

False