Short term control of blood pressure

Question 1

What is the driving force pushing blood through the circulation?

Answer 1

Mean arterial pressure

which is determined by CO x TPR

Question 2

What happens when your MAP is too low?

Answer 2

fainting ( syncope)

Question 3

What happens when your MAP is too high?

Answer 3

Hypertension

Question 4

Where are the arterial baroreflex receptors?

Answer 4

Carotid sinus and aortic arch baroreceptor

Question 5

Describe how baroreceptors work?

Answer 5

They fire when the elastic arteries stretch. More MAP, the more longer artery stretches and the more AP are fired

Question 6

What is the normal MAP value for the normal baroreceptor firing rate?

Answer 6

80mmHg

Question 7

Which nerve does the aortic arch barorecptors send signals to?

Answer 7

Vagus nerve

Question 8

Where does the carotid sinus baroreceptors send signals to?

Answer 8

Glossopharyngeal nerve

Question 9

Where do the vagus and glossopharyngeal nerve synapse?

Answer 9

Medullary cardiovascular centres

Question 10

What is the first nerve effected by the medullary cardiovascular center if the MAP value needs to be changed?

Answer 10

Parasympathetic

Question 11

What node does the parasympathetic system innervate?

Answer 11

Sinoatrial node

Question 12

What node does the sympathetic system innervate/area it affects?

Answer 12

Sinoatrial node

and the adrenal medulla ( due to hormonal component )

Myocardium of the ventricle

Venoconstriction and arteriolar constriction

Question 13

What are other inputs to the medullary cardiovascular centres?

Answer 13

Cardiopulmonary baroreceptors

central chemoreceptors

Chemoreceptors in muscle

Joint receptors
(All feedback responses that detect action but thats not it)

Higher centres

(Feedforward response that causes increased HR before doing something)

Question 14

How do you regulate long term blood pressure?

Answer 14

Revolves around blood volume

Question 15

What are the main sensors for detecting blood volume?

Answer 15

Cardio-pulmonary baroreceptors

Question 16

What types of effects does long term blood pressure have on body?

Answer 16

Hormonal

acts on blood vessels and kindey

Question 17

What is the effect of standing on hydrostatic pressure, EDV, preload, SV, Co, MAP and baroreceptor firing rate?

Answer 17

Increased hydrostatic pressure causes pooling of blood in veins/venules of feet and legs

Decreased EDV, preload, SV, CO, MAP and therefore, baroreceptors firing rate

Question 18

What is the reflex response to standing?

Answer 18

Decreased vagal tone

Increased sympathetic tone

Question 19

What does decreased vagal tone effect?

Answer 19

Increased heart rate

and Cardiac output

Question 20

What does increased sympathetic tone cause?

Answer 20

Increased HR and CO
Increased contractility
Increased venoconstriction, VR, EDV, SV, CO
Therefore increased arteriolar constriction and TPR

Question 21

Define the valsalva manoeuvre

Answer 21

forced expiration against a closed glottis

eg: during defecation

Question 22

Describe what occurs during valsalva manoeuvre

Answer 22

Increased thoracic pressure which is transmitted through the aorta

This causes decrease in venous return, EDV, SV, CO, MAP

MAP detected by baroreceptors which activate the reflex to increase CO and TPR

This causes a decrease in thoracic pressure transmitted through to the aorta

VR is restored so SV increases but reflec effects not worn off

eventually back to normal