Factors Regulating Heart Rate

Question 1

What 3 factors regulate heart rate?

Answer 1

Neural
Hormonal
Intrinsic (venous return)

Question 2

How do neural factors regulate heart rate?

Answer 2

The vasomotor centre (medulla located) responds to changes detected by:

Proprioceptors
Baroreceptors
Chemoreceptors

Question 3

What do baroreceptors do?

Answer 3

detect changes in blood pressure

Question 4

What do chemoreceptors do?

Answer 4

detect changes in blood acidity due to an increase/fall in carbon dioxide.

Question 5

What do proprioceptors do?

Answer 5

detect movement and changes in body position

Question 6

How do receptors cause an increase or fall in heart rate?

Answer 6

Receptors send an impulse to the cardiac control centre in the medulla oblongata which sends an impulse to the SA node either via:
Parasympathetic nervous system to slow heart rate (vagus nerve)
Sympathetic nervous system to increase heart rate (acceleratory nerve)

Question 7

How do hormonal factors affect heart rate?

Answer 7

Adrenaline and noradrenaline released from the adrenal glands

Adrenaline is released into the bloodstream, and stimulates the adrenergic receptors and SA node found in the heart, increasing heart rate.

Release of adrenaline before exercise is known as the anticipatory rise

Question 8

How do intrinsic factors regulate heart rate?

Answer 8

Higher temperature caused through exercising causes increased heart rate as heart works harder to get blood to the skin so heat can be lost as radiation.

Venous return mechanism and the rate at which blood returns to the heart. Blood redistribution needs to be quicker otherwise cardiac output decreases.