Short Term Control of Blood Pressure Flashcards Preview

Cardiovascular System > Short Term Control of Blood Pressure > Flashcards

Flashcards in Short Term Control of Blood Pressure Deck (34):
1

What formula describes mean arteriolar pressure?

MAP = CO x TPR

2

Why does mean arteriolar pressure (MAP) need to be regulated?

Too low leads to fainting (syncope)

Too high leads to hypertension

3

What is the medical name for fainting?

Syncope

4

What is syncope?

Fainting

5

What is the baroreflex?

One of the bodies homeostatic mechanisms that helps to maintain blood pressure at nearly constant levels

6

What is the process of the baroreflex?

1) Aortic arch baroreceptors detect changes in blood pressure and send this information to the medullary cardiovascular centres by the vagus nerve, carotid baroreceptors detect changes and sent this information by the glossopharyngeal nerve

2) Responds by innervating the parasympathetic nerve (vagus) or sympathetic nerve depending on what response is required to return blood pressure to normal

7

What do aortic arch baroreceptors send information to the medullary cardiovascular centre through?

Vagus nerve

8

What do the carotid baroreceptors send information to the medullary cardiovascular centres through?

Glossopharyngeal nerve

9

Where do the aortic arch and carotid baroreceptor sends information to?

Medullary cardiovascular centres

10

What are other inputs to the medullary cardiovascular centres other than aortic arch and carotid baroreceptors?

Cardiopulmonary baroreceptors

Central chemoreceptors

Chemoreceptors in muscle

Joint receptors

Higher centres

11

Can long term regulation of blood pressure be done by arterial baroreceptors?

No, revolves around blood volume

12

How is long term control of blood pressure achieved?

Main sensors are cardiopulmonary baroreceptors

Effects tend to be hormonal

Act on blood vessels and kidneys

13

Is long term control of blood pressure achieved neurally or hormonally?

Hormonally

14

Is short term control of blood pressure achieved neurally or hormonally?

Neurally

15

What do hormones act on to achieve long term control of blood pressure?

Blood vessels and kidneys

16

What are examples of things that are used to achieve long term control of blood pressure?

Renin-angiotensis-aldosterone system

Vasopressin (antidiuretic hormone)

Atrial natriuretic peptide and brain natriuretic peptide

17

How does the renin-angiotensin-aldosterone system regulate blood pressure in the long term?

Angiotensin II causes arteriolar construction and increases total peripheral resistance

Aldosterone increaes Na+ reabsorption and therefore increases plasma volume

18

What effect does angiontensin II have?

Causes arteriolar constriction and increases total peripheral resistance

19

What effect does aldosterone have?

Increases Na+ reabsorption and therefore increases plasma volume

20

What is another name for vasopressin?

Antidiuretic hormone

21

How does vasopressin (antidiuretic hormone) achieve long term regulation of blood pressure?

Causes arteriolar constriction and increases total peripheral resistance

Increases water permeability of collecting duct and therefore increases plasma volume

22

How does atrial natriuretic peptide and brain natriuretic peptide achieve long term regulation of blood pressure?

Causes arteriolar dilation which decreases total peripheral resistance

Increases Na+ excretion and therefore decreases blood volume

23

What is natriuresis?

Excretion of sodium in the urine

24

What is excretion of Na+ in the urine called?

Natriuresis

25

What are examples of when the baroreflex response would be used?

Due to posture

During the valva manoeuvre

26

What is the effect of standing?

Increases hydrostatic pressure causing pooling of blood in veins/venules of feet and legs:

 

Decreases venous return, EDV, preload, stroke volume, cardiac output and mean arterial pressure
Decreases baroreceptor firing rate

27

What is the baroreflex response to standing?

Decreases vegal tone

Increases sympathetic tone

28

What is the impact of decreasing the vagus tone by the baroreflex whilst standing?

Increases heart rate and cardiac output

29

What impact does the baroreflex increasing sympathetic tone when standing have?

Increase heart rate and cardiac output

Increases contractibility and increases stroke volume and cardiac output

Increases vasoconstriction which increases venous return, EDV, stroke volume and cardiac output

Increases arteriolar constriction which increases total peripheral resistance

30

What effect does vasoconstriction have?

Increases venous return, EDV, stroke volume and cardiac output

31

What does the tone of a nerve refer to?

Activity of the nerve

32

33

What is the valva manoeuvre?

Forces expiration against a closed glottis

34

What is the process of the baroreflex being used during the valva manoeuvre?

1) Increase in thoracic pressure is transmitted through the aorta

2) Increase in thoracic pressure causes decrease in venous return, EDV, SV, CO and MAP

3) Decrease in mean arterial pressure is detected by baroreceptors which initiates reflex which increases cardiac output and total peripheral resistance

4) Decrease in thoracic pressure is transmitted through to the aorta

5) Venous return is resorted, so is stroke volume but reflex effects are not worn of

6) Everything returns back to normal

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