The Cardiovascular System

Question 1

Describe the path of blood flow through the heart

Answer 1

1. Superior/ inferior vena cava
2. Right atria
3. Tricuspid valve
4. Right ventricle
5. Pulmonary artery - lungs
6. Pulmonary vein
7. Left atria
8. Bicuspid valve
9. Left ventricle
10. Aorta - muscles and organs

Question 2

What does myogenic mean?

Answer 2

The capacity of the heart to generate its own electrical impulse, which causes the cardiac muscle to contract

Question 3

What happens during diastole?

Answer 3

Relaxation phase. Passive filling of blood in the atria and ventricles

Question 4

What happens during atrial systole?

Answer 4

Contraction of the atria

Question 5

What happens during ventricular systole?

Answer 5

Contraction of the ventricles

Question 6

Explain how the conduction system controls the cardiac cycle

Answer 6

An impulse is sent from the medulla oblongata. It arrives at the SA node. Atrial systole begins. The impulse travels to the AV node but is delayed to allow atrial systole to be completed. The impulse then travels along the Bundle of His to the Purkinje fibres where ventricular systole occurs.

Question 7

Define heart rate

Answer 7

The number of times the heart beats per minute

Question 8

Define stroke volume

Answer 8

The volume of blood ejected from the left ventricle per beat

Question 9

Define cardiac output

Answer 9

The volume of blood ejected from the left ventricle per minute

Question 10

What is the formula linking CO, SV and HR?

Answer 10

HR x SV = CO

Question 11

Define venous return

Answer 11

Volume of blood returning to the heart

Question 12

Give an average value for resting heart rate for both untrained and trained individuals

Answer 12

Untrained: 70-72bpm
Trained:5obpm

Question 13

Give an average value for resting stroke volume for both untrained and trained individuals

Answer 13

Untrained: 70ml
Trained: 100ml

Question 14

Give an average value for resting cardiac output for both untrained and trained individuals

Answer 14

Untrained: 5l/min
Trained: 5l/min

Question 15

What is the difference between sub-maximal exercise and maximal exercise?

Answer 15

Sub-maximal: low-to-moderate intensity. Associated with aerobic work
Maximal: high intensity. Associated with anaerobic work and fatigue

Question 16

What happens to heart rate BEFORE sub-maximal exercise commences? (graph)

Answer 16

Increases due to an anticipatory rise caused by adrenaline

Question 17

What happens to heart rate DURING sub-maximal exercise? (graph)

Answer 17

There is a rapid increase to increase blood flow and oxygen delivery. The graph then plateaus and the heart rate is at a steady state as oxygen supply=oxygen demand

Question 18

What happens to heart rate AFTER sub-maximal exercise? (graph)

Answer 18

Rapid decrease as recovery begins and then a more gradual decrease to bring HR to resting levels

Question 19

How does the graph of heart rate over time during maximal exercise differ from the graph of sub-maximal exercise?

Answer 19

Does not plateau as exercise intensity continues to increase. There is a growing demand for oxygen and waste removal so HR must meet this demand -rapid increase then slower increase

Question 20

Why does stroke volume increase due to increased venous return?

Answer 20

There is a greater volume of blood returning to the heart so greater volume of blood can be ejected

Question 21

What is Starling’s law?

Answer 21

Shows how stroke volume is dependent on venous return. Greater venous return causes greater pressure in ventricles which causes greater stretch on the ventricular walls. This increase the force of contraction so a greater volume of blood is ejected from the heart