short term control of blood pressure

Question 1

Recognise the importance of regulating mean arterial pressure.

Answer 1

MAP is the driving force pushing blood through circulation. Too low- fainting
Tooo high- hypertension in the long term

Question 2

Describe the components and function of the arterial baroreceptor reflex.

Answer 2

Mechanims the body uses to maintain normal blood pressure. specialised neurons called baroreceptors which are stretch receptors found in the arctic arch and carotid sinus. They respond to increase blood pressure and walls stretch and fire more action potentials. sent via vagus and pharrogeneal nerves to nucleus of tractus solutarious. This activated PSNS and inhibited SNS. para releases acetylcholine which acts on pacemaker cells of sinoatrial node which in turn decreases heart rate and stroke volume.

Question 3

Identify other inputs to the medullary cardiovascular centres.

Answer 3

1. cardiopulmonary baroreceptors- sense central blood volume
2. central chemoreceptors - sense arterial increase of co2 and decrease in oxygen.
3. chemoreceptors in muscle- sensing metabolite concentratin
4. joint receptors- sense joint movement
5. higher centres- hypothalamus and central cortex

Question 4

Explain the relationship between cardiac output, total peripheral resistance, and mean arterial pressure.

Answer 4

MAP = CO x TPR

Question 5

Review the importance of coordinated control of the cardiovascular system using the response to exercise as an example.

Answer 5

Local cardiovascular control mechanisms control the radius of peripheral arteries and influence cardiac output.
During exercise, efficient delivery of oxygen to working skeletal and cardiac muscles is vital for maintenance of ATP production by aerobic mechanisms.

Question 6

Describe the effect of changes in posture on the cardiovascular system.

Answer 6

On the transition from sitting in a chair to standing, blood is pooled in the lower extremities as a result of gravitational forces. Venous return is reduced, which leads to a decrease in cardiac stroke volume, a decline in arterial blood pressure, and an immediate decrease in blood flow to the brain.

Question 7

Describe the effect of the Valsalva manoeuvre on the cardiovascular system

Answer 7

forced expiration against a closed glottis
phase 1- increased thoracic pressure
phase 2- heart rate increases as harder to get blood back to heart and everything decreases
phase 3- decreased thoracic pressure is transmitted through to the aorta hence the drop
phase 4- massive rebound and blood comes flooding in