Regulation of blood pressure and hypertension

Question 1

how is mean arterial pressure calcualted ?

Answer 1

diastolic pressure+ 1/3 Pulse pressure

Question 2

what is the normal range of Mean arterial blood pressure (MAP)

Answer 2

70-105 mmHg

Question 3

what is the minimum pressure needed for perfusion of coronary arteries, brian, kidneys

Answer 3

60mmHg

Question 4

what 2 reasons MAP is regulated within a narrow range

Answer 4

1. Pressure is high enough to perfuse internal organs
2. Pressure is not too high to damage the blood vessels or place extra strain on the heart( afterload)

Question 5

what does cardiac ouput x total peropheral resistance equal

Answer 5

mean arterial pressure

Question 6

how is cardiac output calucalted ?

Answer 6

SVx Heart rate

Question 7

what is stroke volume

Answer 7

volume of blood pumped by each centricle of the heart per heart beat.

Question 8

What is Total periphreal resistance

Answer 8

TPR is the sum of resistance of all peripheral vasculature in the sustemic circulation

Question 9

MAP is linked to CO and TPR

Answer 9

MAP = (SV xHR) xTPR

Question 10

what is the total amount of resistnace arteriaoles account for ?

Answer 10

about 50%

Question 11

what regulates TPR

Answer 11

vascular smooth muscles

Question 12

vascular smooth muscles are suppiled by what nerve fibers and what neurotrabsmitter is acting on what recpetor

Answer 12

synoathetic nerve fibers

noradrenaline

alpha adrenerguc receptors

Question 13

what is vasomtoer tone

Answer 13

partial constriction of vascular smooth muscles at rest

Question 14

how does vasomotor tone come about?

Answer 14

tonic discharge of sympathetic nerves resulting in noradrenaline release

Question 15

what system modifies TPR

Answer 15

autonomic nervous system.

Question 16

what do baroreceptors do and where are they located

Answer 16

cartoid sinus and aortic arch

they regulate arterial blood pressure inlcuding prevention of postrual changes

Question 17

where do carotid and aortic baroreceptors signle to and what nerve

Answer 17

they signal to the medulla

via

glossopharyngeal (IX)

vagus (X)

Question 18

what sort of changes do barorepectors react to

Answer 18

acute changes in the blood pressure. therefore constant HBP leads to decrease fiiring in the baroreceptors.

Question 19

resetting of baroreceptors does what?

Answer 19

resetting of baroreceptors will lead to a new steady state level at which they will fire at

Question 20

Control of MAP/ blood volume is done through

Answer 20

controlling the extracellular fluid volume.

Question 21

wha percentage of body wieght is water

Answer 21

60%

Question 22

what fraction of total body fluid is intracellular and extraceullular fluid

Answer 22

ICF= 2/3

ECF= 1/3

Question 23

how is extracellular fluid volume calculated

Answer 23

plasma volume+ interstitial fluid volume (baths all cells)

Question 24

what happens if plasma volume falls

Answer 24

compensatory mechanism shifts fluid from interstitial cmpartnments to plasma compartments.

Question 25

what 2 factors affect ECFV. how are these factors regulated?

Answer 25

**water excess/ deficit** **Sodium intake/out take from diet.** hormons act as effectors to regulate the extracellular fluid volume by regulating the water and salt balance in our bodies

Question 26

what endocrine system controls ECFV

Answer 26

1. renin-angiotensin-aldoserone system 2. Antidiuretic hormone ( arginine vasoperssin ) 3. Atrial natriuretic peptide (ANP)

Question 27

how is angiotensin 2 produced ?

Answer 27

angiotensinogen + renin--\> angiotensin 1 angoitensin 1 + angiotensin- converting enzyme --\> angiotensin 2

Question 28

what are the affects of angiotensin 2

Answer 28

acts on adrenal cortext to release aldosterone ( increase thirst and vasopressin( reabsorption of H2O by kidney) arteriolar vasoconstriction

Question 29

what does renin do?

Answer 29

released from the kidneys and stimulates the formation of angiotensin 1 in the blood from angiotensinogen (produced by the liver)

Question 30

angiotension 1 is converted to ?

Answer 30

angiotensin 2 by angiotensin converting enzyme ( ACE which is produced by pulmonary vasular endothelium)

Question 31

what does Angiotension 2 stimulate ?

Answer 31

release of aldesterone from adrenal cortex systemic vasoconstriction= increase TPR increase in thrist and ADH= increase in plasma volume.

Question 32

what does aldestorne do

Answer 32

steriod hormone acts on the kdineys to increase sodium and wanter rention which in turns acts to increase plasma volume

Question 33

antidiurectic hormone- Vasopressin where is it made and stored

Answer 33

hormone precursor made in the hypothalamus and stored in the posterior pituitary

Question 34

when is vasopressin secreted

Answer 34

drop in extracellular fluid volume and increased extracellular fluid osmolarity

Question 35

what is normal osmolarity of the extracellular fluid ?and how is it measured ?

Answer 35

280milli-osmoles/L it is measured by osmoreceptors in the brain close proximity to the hypothalmus. increase in osmilarity will increase release of ADH

Question 36

what is the role of Atrial Natruiret peptide (ANP)

Answer 36

released when in atrial distension ( hypervolemic state) causes excretion of slat water in the kidneys and reduces blood volume and pressure. vasodilator decrease renin secretion as it is the counter measure.

Question 37

baroreceptors regulate

Answer 37

short term moment to moment regulation of MAP

Question 38

long term regulation of MAP involves ?

Answer 38

control of blood volume by hormones

Question 39

what does ADH regulate

Answer 39

ECF volume and osmolarity

Question 40

what does Aldosterone regulate ?

Answer 40

total body sodium with it EFC volume in the long run