Control of BP

Question 1

What part of the nervous system controls BP?

Answer 1

Sympathetic

Question 2

Name the 3 ways in which the sympathetic NS controls BP

Answer 2

1. ) Resistance vessel tone
2. ) Atrial ventricular node and sinoatrial node
3. )Venous tone

Question 3

Elaborate on how the SNS control PB through resistance vessel tone

Answer 3

The SNS manages peripheral resistance through contracting and dilating the vessels.
This has an effect on BP because it affects total peripheral resistance (TPR)

Question 4

Elaborate on how the SNS control PB through the Atrial ventricular node and sinoatrial node

Answer 4

The SNS controls heart rate and Stroke volume through its effect on Beta receptors in the heart.
HR X SV = CO so BP is affected throught the SNS’s effect on Cardiac output

Question 5

Elaborate on how the SNS control PB through Venous tone?

Answer 5

Controls venous return i.e ensures that the right amount of blood is returned to the heart (PRELOAD) . This has an effect on cardiac filling pressure.
How much blood enters the heart affects Cardiac output.

Question 6

What are the inhibitory inputs that control BP?

Answer 6

Atrial Baroreceptors in the aortic arch and the carotid sinus send feedback about what the BP is doing back to the brain. If BP is too high sympathetic tone will be reduced

Question 7

What three thing will affect total peripheral resistance (TPR)?

Answer 7

1. ) blood viscosity
2. ) The length of the vessel
3. ) The radius of the vessel (to the power of 4 = this has the biggest effect)

Question 8

How will an increase TPR effect MAP?

Answer 8

An increase in TPR leads to and increase in MAP

MAP = TPR X CO

Question 9

Changes in smooth muscle tone i.e. the ability to vasoconstrict and vasodilate will help control BP (resistance vessel tone) .How will vasoconstriction effect peripheral resistance and BP?

Answer 9

Vasoconstriction = increase Peripheral resistance (TPR) = Increased BP