Regulation Of Gas Content In Blood 🫀

Question 1

Regulation of carbon dioxide concentration in blood by negative feedback mechanism

Answer 1

Fall in blood ph (rise in co2) is detected by chemoreceptors in aortic bodies, carotid bodies and respiratory centre.
Chemoreceptors send nerve impulses to respiratory centre.
The respiratory centre send more nerve impulses to the intercostal muscle and diaphragm muscle causing them to contract faster and more strongly.

Question 2

Name the three stages in cardiac cycle

Answer 2

Atrial systole
Ventricular systole
Diastole

Question 3

During ventricular systole, describe the blood flow and which valve close and open

Answer 3

Right ventricle—>pulmonary artery
Left ventricle—>aorta

Semilunar valves open
Tricuspid and bicuspid valve close making the first sound ’lub’

Question 4

During diastole, describe the blood flow and which valves open and close

Answer 4

Venae cavae —>right atrium
Pulmonary veins—> left atrium

Semilunar valves close causing the sound ‘dub’
Bicuspid and tricuspid valves open

Question 5

Which nerve stimulates the SA node

Answer 5

Sympathetic nerve

Question 6

Which nerve inhibits SA node

Answer 6

Parasympathetic nerve / vagus nerve

Question 7

Which neurotransmitter do sympathetic nerve and parasympathetic nerve release respectively?

Answer 7

Noradrenaline and acetylcholine

Question 8

Describe the process of nervous control of cardiac output

Answer 8

Receptors send nerve impulses to cardiovascular centre
The cardiovascular centre sends nerve impulses to the SA node and cardiac muscle through the sympathetic nerve and parasympathetic nerve
The sympathetic nerve stimulates the activity of the SA node and cardiac muscle , increasing the stroke volume and heart rate
/ the parasympathetic nerve inhibits the activity of SA node and cardiac muscle, decreasing heart rate and stroke volume

Question 9

Under hormonal control, what do the sympathetic nerve stimulates?

Answer 9

The adrenal gland in kidney to release more adrenaline into the blood
Adrenaline stimulates the SA node and cardiac muscle, causing it contract more frequently and more forcefully
This increase the heart rate and stroke volume , increase the cardiac output

Question 10

What will muscle do during exercising?

Answer 10

Carry out anaerobic respiration to produce lactic acid
Lactic acid will accumulate in muscle leading to muscle fatigue

Question 11

SA node generate what impulses to cardiac muscle?

Answer 11

Electrical impulses
X nerve impulses