cardiac cycle TOPIC 3

Question 1

What is meant by cardiac muscle being “myogenic”?

Answer 1

Cardiac muscle can contract and relax without nervous / hormonal stimulation. [only requires a supply of oxygen + glucose].

Question 2

What happens when your coronary arteries become blocked?

Answer 2

If coronary arteries become blocked, cardiac muscle won’t receive oxygen, therefore will not be able to respire and the cells will die.
This results in myocardial infarction [heart attack].

Question 3

Describe the function of the coronary arteries [2].

Answer 3

Carry oxygen/glucose to heart [cardiac] muscle.

Question 4

Describe the mechanism by which the arteriole regulates blood flow to capillaries. [2]

Answer 4

The smooth muscle within the arteriole contracts.
The contraction leads to narrowing/constriction of the arteriole lumen.

Question 5

List all the blood vessels you need to know:

Answer 5

-vena cava
-aorta
-pulmonary artery [lungs]
-pulmonary vein
-renal artery [kidney]
-renal vein

Question 6

Suggest why there are larger fluctuations in blood pressure in the aorta than in the small arteries. [AO2: 3 MARKS]

Answer 6

M1: Aorta is close to the heart
M2: It has elastic tissue
M3: It can stretch
[because it has elastic tissue it stretches when there is contraction and recoils during diastole/relaxation]