Regulation of Arterial Pressure

Question 1

TPR

effects of decreasing and increasing TPR

Answer 1

total peripheral resistance: determined by arterioles

a decrease in TPR causes an increase in venous return/CO
an increase in TPR will reduce venous return/CO

Question 2

increasing TPR does what to arterial and venous pressure?

Answer 2

increases arterial pressure but decreases venous pressure

Question 3

decreasing TPR does what to arterial and venous pressure

Answer 3

decreases arterial pressure and an increase in venous pressure

Question 4

Increasing TPR effects CO or vasculature?

Answer 4

both: it INCREASES arterial pressure, so it must increase the afterload on the heart

Question 5

Decreasing TPR effects CO or vasculature?

Answer 5

both: it DECREASES arterial pressure, to it decreases the afterload on the heart

Question 6

Mean arterial pressure

Answer 6

the pressure in the major arteries delivering blood are basically the same: 100 mmHg. this pressure remains the same throughout major artery, but delivery pressure itself is controlled at the individual level by metabolic means

Question 7

what is mean arterial pressure

Answer 7

100 mmHg

Question 8

what is the formula for mean arterial pressure

Answer 8

P = CO x TPR

Question 9

what is “deceptive” about the mean arterial pressure formula?

Answer 9

CO and TPR are not independent variables, so effecting one will effect the other. thus P won’t follow simple logic of an equation because it’s based on variables that alter one another.

Question 10

Baroreceptors

Answer 10

located in carotid sinus and aortic arch

Question 11

baroreceptors in the carotid sinus

Answer 11

respond to increases and decreases in pressure

Question 12

baroreceptors in the aortic arch

Answer 12

respond to increases in pressure

Question 13

baroreceptors are

Answer 13

“mechanoreceptors” which are sensitive to pressure or stretch

Question 14

Which is the strongest stimulus on the baroreceptor:

Absolute pressure level
Rate of pressure changes
Changes in pressure

Answer 14

rate and changes

Question 15

local arterial bed rely on a _____ input pressure to control how much blood the tissue receives

Answer 15

constant, high input pressure

Question 16

Two control mechanisms for blood flow to local vascular beds

Answer 16

1) maintain a constant, high input pressure

2) ability to alter resistance to flow through individual vascular beds

Question 17

Two general mechanisms for controlling blood flow

Answer 17

neuronal (baroreceptors) and hormonal

Question 18

carotid sinus baroreceptors —>

Answer 18

herrings nerves —> CN IX

Question 19

CN IX —>

Answer 19

+ stimulus at the Vasomotor center (medulla – nucleus tractus solitarus) —> cardiac decelerator —> (-) @ SA node

Question 20

information from the aortic arch is carried by the

Answer 20

vagus nerve

Question 21

information from the carotid sinus is carried by the

Answer 21

glossopharyngeal center

Question 22

Vasomotor Center

how it is stimulated and what it does

Answer 22

baroreceptor input (increased pressure) decreases sympathetic activity and increases parasympathetic activity (decreasing heart rate)

decrease pressure –> decreased firing —> increased sympathetic activity

Question 23

Increase in Pa —>

Answer 23

stimulation of X and IX —> vasomotor center in medulla —> increase in parasympathetics + decrease in sympathetics ———> negative stimulus of SA node + decrease sympathetic stimulation of contraction and SA —> relaxation of heart and vasodilation —> Pa brought down back to normal

Question 24

Sympathetic system causes (3 things)

Parasympathetic system causes (1 thing)

Answer 24

constriction of arterioles and veins via alpha receptors

increases HR and contractility via beta-1 receptors

causes fluid retention by kidney due to afferent arteriolar constriction and increased renin secretion

Decrease in heart rate (muscarinic receptors)

Question 25

Three centers in the Vasomotor center

Answer 25

Vasoconstrictor center, Cardiac accelerator center, and cardiac decelerator center

Question 26

what happens when the cardiac decelerator center is positively stimulated?

Answer 26

it causes inhibition of SA node

Question 27

Renin-Angiotensin-II-Aldosterone System sequence leading to RENIN release

Answer 27

regulates Pa decreased renal profusion ---> mechanoreceptors in afferent arterioles --> decrease in Pa causes Prorenin to be converted to renin in juxtaglomerular cells OR beta-1 receptor stimulation on juxtaglomerular cells --> renin release

Question 28

Renin-Angiotensin-II-Aldosterone System sequence leading to Angiotensin II release

Answer 28

Renin converts angiotensinogen to angiotensin I | angiotensinogen

Question 29

angiotensin II in the heart and lungs specifically

Answer 29

catalyzed from angiotensin I by angiotensin converting enzyme (ACE) in the heart and lungs increase blood volume, preload, stroke volume, CO and therefore BP

Question 30

Angiotensin II apart from heart and kidneys, where does this protein work?

Answer 30

vascular smooth muscle, brain, and adrenal cortex it stimulates G coupled protein-couple angiotensin II receptors (ATi) i

Question 31

Angiotensin II ---> aldosterone

Answer 31

increases aldosterone, which increases sodium reabsorption kidneys

Question 32

Angiotensin II --> Na-H exhcnager

Answer 32

increases their activity in the kidneys, stimulating sodium reabsorption

Question 33

Angiotensin II --> hypothalamus

Answer 33

increases thirst and release antidiuretic hormone

Question 34

Angiotensin II ---> arterioles

Answer 34

increase TPR ---> increasing arterial pressure achieves this by binding to g coupled protein receptors and causing an upswing of cAMP-->IP3-->DAG--->Ca2+

Question 35

big picture theme of Pa's relationship to angiotensin II

Answer 35

as Pa decreases, angiotensin II tries to restore it

Question 36

why is the baroreceptor induced over the hormone method of restoring Pa, and vice versa?

Answer 36

baroreceptors can work in seconds but are considered long term and short term mechanisms hormones are needed for long term pressure maintenance

Question 37

from Ballam slides angiotensin I is converted by ____ in the _____. (1) angiotensin I is converted to ____ in the _____ as well (2)

Answer 37

angiotensin converting enzyme in the blood and in the kidneys as well

Question 38

"ultimate relationships" angiotensin II ---> aldosterone --->......

Answer 38

angiotensin II ---> aldosterone from adrenal cotex ---> Na-H pump in the kidneys ---> Na retention ---> water reuptake ---> Pa ---> increased preload -->increased SV --> increased CO --> increased BP

Question 39

ADH

Answer 39

released by hypothalamus in response to angiotensin II binds to receptors on arterioles and causes vasoconstriction (increasing TPR) binds to kidney cells and stimulate reabsorption remember: angiotensin II ---> site of action ---> increased blood volume --> increased preload ---> increased SV ---> increased CO ---> increased BP --> increased Pa

Question 40

vasopressin

Answer 40

ADH

Question 41

side effect of ACE inhibitors

Answer 41

angiotensin converting enzyme convers angiotensin I to II, but it also breaks down bradykinin which accumulates and can make you cough

Question 42

ARBs

Answer 42

angiotensin receptor blockers

Question 43

cerebral ischemia

Answer 43

causes increased sympathetic outflow from vasomotor center

Question 44

Hemorrhage cause blood to

Answer 44

drop means loss of blood volume

Question 45

Hemorrhage causes what parts of the vasomotor to work, and how

Answer 45

decreased blood volume ---> decreased stretch on baroreceptors at carotid sinus --> decreases signals to brain--> induce sympathetics in heart ---> heart rate/contractility increase ---> decreases unstressed volume

Question 46

Valsalva maneuver

Answer 46

expiring against a closed glottis causes increase in intrathoracic pressure decreases venous return

Question 47

Cushing reflex

Answer 47

as intracranial pressure increases, cerebral arteries are compressed --> decreased perfusion in the brain CO2 and therefore H is not removed from the brain, so the pH drops, which causes medullary chemoreceptors to cause sympathetic outflow toward brain in a nuttshell: intracranial pressure redues blood flow to medulla, activating sympathetics to increase outflow to brain. over all effect is increase in TPR and Pr

Question 48

Vasopressin is released

Answer 48

in response to angiotensin II from brain also released by r. atria in response to low preload causes increased TPR and water retention

Question 49

Natriuretic peptide :ABC

Answer 49

Atrial, Brain, C-type causes arteriolar dilation, increases fluid loss inhibits renin decrease TPR at atrioles secreted by excessive preload of atria and ventricles