Short term control of blood pressure

Question 1

Importance of MAP regulation

Answer 1

Syncope

Hypertension

Question 2

Baroreceptors

Answer 2

Stretch receptors that respond to pressure-induced stretching of the blood vessel wall in which they are found

Question 3

Baroreceptor locations (2) and transmission

Answer 3

Carotid sinus: transmitted in the glossopharyngeal nerve to the medullary CV centres

Aortic arch: transmitted in the vagus nerve to the medullary CV centres

Question 4

Medullary cardiovascular centre inputs (5)

Answer 4

1. Cardiopulmonary baroreceptors in heart/lungs (plasma volume high)
2. Central chemoreceptors (detects high CO2 and increases blood flow)
3. Muscle chemoreceptors (increase metabolite concentration)
4. Joint receptors
5. Higher centres (increased HR, feed-forward)

Question 5

CVS effect on baroreceptor due to change in posture

Answer 5

Decreased baroreceptor firing

Question 6

Decreased baroreceptor firing reflex response (2)

Answer 6

1. Decreased vagal tone

2. Increased sympathetic tone

Question 7

Valsalva manoeuvre

Answer 7

Forced expiration against a closed glottis.
1. Increased thoracic pressure
2. Decreased VR
3. Decreased MAP detected by baroreceptors and reflex response initiated
Breath out
4. Decrease in thoracic pressure
5. VR is restored and reflex is still present
6. Baroreceptors firing rate increases and reflex is inhibited

Question 8

Valsalva manoeuvre: diagnostic

Answer 8

Cardiac hypertrophy

Valve regurgitation/stenosis/prolpase

Question 9

Valsalva manoeuvre: therapeutic

Answer 9

Supraventricular tachycardia