Short Term Control of Blood Pressure

Question 1

MAP is

Answer 1

The driving force pushing blood through the circulation

Question 2

Result if MAP is too low

Answer 2

Fainting (syncope)

Question 3

Result if MAP is too high

Answer 3

Hypertension

Question 4

Receptors of blood pressure involved in arterial baroreceptor reflex

Answer 4

Aortic arch baroreceptor and carotid sinus baroreceptors

Question 5

Baroreceptors indirectly measure pressure by measuring

Answer 5

Stretch

Question 6

As MAP increases, baroreceptor firing

Answer 6

Increases

Question 7

Two sensory nerves of arterial baroreflex

Answer 7

Vagus nerve

Glossopharyngeal nerve

Question 8

Two motor nerves of arterial baroreflex

Answer 8

Parasympathetic vagus nerve

Sympathetic nerves

Question 9

Medullary cardiovascular centres

Answer 9

Several different groups of neurons in medulla communicating that take impulses of MAP and decide what to do about it

Question 10

Outcomes of the arterial baroreflex via parasympathetic nerves

Answer 10

Decreases blood pressure via sinoatrial node depolarising less

Question 11

Outcomes of the arterial baroreflex via sympathetic nerves (not including smooth muscle)

Answer 11

Increase blood pressure via sinoatrial node depolarising more, adrenal medulla releasing adrenaline, myocardium releasing more calcium ions from sarcoplasmic reticulum increasing contractility and so SV

Question 12

Outcomes of the arterial baroreflex via smooth muscle (controlled by sympathetic nerves)

Answer 12

Vasoconstriction increasing stroke volume and arteriolar constriction increasing TPR

Question 13

Other inputs to the medullary cardiovascular centres

Answer 13

Cardiopulmonary baroreceptors
Central chemoreceptors
Chemoreceptors in muscle
Joint receptor
Higher centres

Question 14

Cardiopulmonary baroreceptors

Answer 14

In the walls of the vessels in heart and lungs which are the low pressure parts of circulation, detect increase in blood pressure

Question 15

Central chemoreceptors

Answer 15

Detect carbon dioxide levels, more co2 = more o2 and so increase in blood pressure

Question 16

Chemoreceptors in muscle

Answer 16

Respond to high potassium ion concentration or acidity, signify high metabolic activity, need more blood so increase blood pressure

Question 17

Joint receptors

Answer 17

Greater work in joints requires more blood and so increases blood pressure

Question 18

Higher centres

Answer 18

Feed forward effect in the cortex effected by emotions

Question 19

Main sensors in the regulation of blood pressure in the long term

Answer 19

Cardiopulmonary baroreceptors

Question 20

Long term regulation of blood pressure act on

Answer 20

Vessels and kidneys

Question 21

Result of standing up

Answer 21

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

Question 22

Effect of standing on blood pressure

Answer 22

Decrease in VR, EDV, preload, SV, CO, MAP and baroreceptor firing

Question 23

Reflex response to blood pressure changes due to standing

Answer 23

Decrease in vagal tone so no longer slowing down the heart increasing HR and CO
Increase in sympathetic tone increasing HR, contractility, venoconstriction and arteriolar constriction

Question 24

The Valsalva manoeuvre

Answer 24

Forced expiration against a closed glottis

Question 25

Result of Valsalva manoeuvre

Answer 25

Increases thoracic pressure which is transmitted through to aorta

Question 26

Effect of Valsalva manoeuvre on blood pressure

Answer 26

Reverses pressure gradient, decrease in VR, EDV, SV, CO, MAP

Question 27

Reflex response to blood pressure changes due to Valsalva manoeuvre

Answer 27

Decrease in MAP is detected by baroreceptors which initiates reflex and increases CO and TPR, the decrease in thoracic pressure is transmitted through to aorta and VR so SV is restored but reflex effects not worn off, then return to normal

Question 28

Regulation of blood pressure in the long term revolves around

Answer 28

Blood volume