Q: Which formula correctly represents cardiac output ($$CO$$)?

$$CO = (Heart\ Rate) \times (Stroke\ Volume)$$

Q: A professional endurance cyclist has a resting heart rate of 32 bpm and a stroke volume of 200 mL. What is their resting cardiac output?

$$CO = 32 \times 200 = 6400\ mL/min$$

Q: A patient has a heart rate of 80 bpm and a stroke volume of 70 mL. What is their cardiac output?

$$CO = 80 \times 70 = 5600\ mL/min$$

Question 1

Which of the following best describes cardiac output?

Accepted Answer

The volume of blood pumped by the heart per minute

Question 2

Which formula correctly represents cardiac output ($$CO$$)?

Accepted Answer

$$CO = (Heart\ Rate) 	imes (Stroke\ Volume)$$

Question 3

During intense exercise, which of the following changes is most likely to occur in a healthy adult?

Accepted Answer

Increase in both heart rate and stroke volume

Question 4

A professional endurance cyclist has a resting heart rate of 32 bpm and a stroke volume of 200 mL. What is their resting cardiac output?

Accepted Answer

$$CO = 32 	imes 200 = 6400\ mL/min$$

Question 5

Which of the following best explains the Frank-Starling effect?

Accepted Answer

The force of cardiac contraction increases as the sarcomere length increases, up to an optimal point

Question 6

Which of the following would most likely increase end-diastolic volume (EDV)?

Accepted Answer

Increased venous return

Question 7

If a patient’s end-diastolic volume is 140 mL and their end-systolic volume is 60 mL, what is their stroke volume?

Accepted Answer

$$SV = 140 - 60 = 80\ mL$$

Question 8

Which of the following is a direct effect of increased sympathetic nervous system activity on the heart?

Accepted Answer

Increased heart rate and contractile force

Question 9

Which ion channel is primarily responsible for the depolarization phase in pacemaker cells of the heart?

Accepted Answer

L-type calcium channels

Question 10

A patient has a heart rate of 80 bpm and a stroke volume of 70 mL. What is their cardiac output?

Accepted Answer

$$CO = 80 	imes 70 = 5600\ mL/min$$

Question 11

Which of the following best describes the physiological reason why stroke volume increases during exercise?

Accepted Answer

Increased end-diastolic volume due to greater venous return

Question 12

Which of the following is NOT a way to increase oxygen delivery to tissues?

Accepted Answer

Decrease the heart rate

Question 13

Which of the following statements about the autonomic nervous system’s effect on the heart is correct?

Accepted Answer

Sympathetic stimulation increases both heart rate and contractility

Question 14

Which of the following best explains why elite endurance athletes can achieve much higher cardiac outputs during exercise compared to average individuals?

Accepted Answer

They have a much greater stroke volume

Question 15

Which of the following would most likely occur if the L-type calcium channels in cardiac contractile cells were blocked?

Accepted Answer

Decreased force of contraction

Question 16

A patient’s heart rate increases from 60 bpm to 120 bpm during exercise, but their stroke volume remains constant at 70 mL. By what factor does their cardiac output change?

Accepted Answer

It doubles

Question 17

Which of the following best describes the relationship between sarcomere length and force of contraction in cardiac muscle?

Accepted Answer

Force of contraction decreases as sarcomere length increases beyond the optimal range

Question 18

Which of the following is a direct effect of increased epinephrine on the heart?

Accepted Answer

Increased heart rate and contractility

Question 19

If a person’s end-diastolic volume increases but their end-systolic volume remains the same, what happens to their stroke volume?

Accepted Answer

Stroke volume increases

Question 20

Which of the following best explains why the heart rate decreases during sleep?

Accepted Answer

Increased parasympathetic nervous system activity

Cardiac Output and Regulation: Cardiovascular Physiology Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard