[Biology] How Blood Pressure is Regulated

(10 marks essay)

Blood pressure is regulated by a negative feedback mechanism.

a) Blood pressure increases during strenuous exercise

1. Baroreceptor in the wall of the aorta and carotid arteries are stimulated.
2. Rate of nerve impulse increase, 
3. the impulse is sent at a faster rate 
4. to Cardiovascular centre in the medulla oblongata.
5. Nerve impulses (parasympathetic nerve) are sent to effectors
6. Causing relaxation (vasodilation) of smooth muscle in the blood vessel wall 
7. resistance of the blood flow in blood vessels reduces, 
8. weaker cardiac muscle contraction and 
9. decrease of heartbeat rate 
10. thus caused the blood pressure decreases and regulate to normal blood pressure.

b) Blood pressure decreases when in a state of shock

1. Baroreceptor in the wall of the aorta and carotid arteries are less stimulated.
2. Rate of nerve impulse decrease, 
3. the impulse is sent at a slower rate 
4. to Cardiovascular centre in the medulla oblongata.
5. Nerve impulses (sympathetic nerve) are sent to effectors 
6. Causing contraction (vasoconstriction) of smooth muscle in the blood vessel wall 
7. resistance of the blood flow in blood vessels increase, 
8. stronger cardiac muscle contraction and 
9. increase of heartbeat rate 
10. thus causing the blood pressure decrease and regulate the blood pressure to the normal blood pressure.

Baroreceptor

**to detect the pressure of blood 

@ arch of aorta & carotid arteries.