Control of heart rate

Question 1

How is the heartbeat initiated and propagated through the heart.

Answer 1

-Sinoatrial node (SAN) sends wave of electrical impulses causing atria to contract.
-Non conductive tissue prevents immediate contraction of ventricles. –The AVN delays impulse whilst blood leaves atria.
-The AVN then sends waves of electrical impulses down the Bundle of His.
-This causes ventricles to contract from base up.

Question 2

Role of medulla oblongata

Answer 2

Controls the changes in the heart rate.

Question 3

Baroreceptors

Answer 3

Detect blood pressure in the carotid arery and aorta

Question 4

Chemoreceptors

Answer 4

Detect concentration of CO2 in blood flowing through the Carotid artery.

Question 5

Role of baroreceptors

Answer 5

Located in aorta and carotid arteries
They are stimulated by high/low blood pressure .

High blood pressure