Control of Circulation

Question 1

What mechanisms regulate Ca entry?

Answer 1

Pharmacomechanical coupling, electrochemical coupling, Ca-calmodulin complex

Question 2

How does pharmacomechanical coupling work?

Answer 2

G-protein activates PLC which activates IP3 which increases Ca release

Question 3

How does electromechanical coupling regulate Ca entry?

Answer 3

Ca is released via voltage gated channels in the sarcolemmaq

Question 4

How does the Ca-Calmodulin complex work?

Answer 4

Ca binds to calmodulin to change its comformation, it phosphorylates inactive myosin through ATP hydrolysis, ATP binds to myosin causing it to flex

Question 5

What are the intrinsic mechanisms for the control of peripheral blood flow?

Answer 5

autoregulation, metabolic regulation, and endothelial regulation

Question 6

What is the MOST important intrinsic mechanism to control peripheral blood flow?

Answer 6

Metabolic regulation

Question 7

What is the end result of metabolic regulation?

Answer 7

the washout of CO2, lactic acid, and metabolites

Question 8

What does metabolic regulation depend on?

Answer 8

basal tone

Question 9

What is active hyperemia?

Answer 9

increase in organ blood flow that is associated with increased metabolic activity of an organ or tissue

Question 10

What is reactive hyperemia?

Answer 10

the transient increase in organ blood flow that occurs following a brief period of ischemia

Question 11

What is ischemia?

Answer 11

an inadequate blood supply to an organ or part of the body

Question 12

What is autoregulation?

Answer 12

the constant flow of blood to tissue despite blood pressure fluctuations

Question 13

What does increased transmural pressure cause?

Answer 13

vasoconstriction

Question 14

In what range does autoregulation maintain flow?

Answer 14

60-190 mmHg

Question 15

Below the autoregulatory range, what happens to flow?

Answer 15

it decreases as perfusion pressure decreases

Question 16

What is critical closing pressure?

Answer 16

when blood pressure is below critical value

Question 17

What happens when BP is below critical closing pressure?

Answer 17

arterioles close and flow stops

Question 18

What regulates endothelial regulation?

Answer 18

paracrines

Question 19

What does nitric oxide cause?

Answer 19

vasodilation

Question 20

What does prostacyclin cause?

Answer 20

vasodilation

Question 21

What does endothelin I cause?

Answer 21

vasoconstriction

Question 22

What are extrinsic mechanisms of peripheral blood flow

Answer 22

Nervous system and humoral regulation, sympathetic, and parasympathetic

Question 23

Is extrinsic control necessary for peripheral blood flow?

Answer 23

no

Question 24

When does nervous system and humoral regulation come into play?

Answer 24

during exercise, hemorrhage, and the like

Question 25

What is the adrenergic response?

Answer 25

sympathetic control

Question 26

How does the adrenergic response work?

Answer 26

it releases norepinephrine to activate the cardiovascular system

Question 27

What is the adrenergic response also known as?

Answer 27

the pressor response

Question 28

What is the cholinergic response?

Answer 28

parasympathetic control

Question 29

How does the cholinergic response work?

Answer 29

acetyl choline release to inhibit the heart

Question 30

What are baroreceptors?

Answer 30

stretch receptors

Question 31

Where type of baroreceptors are there?

Answer 31

atrial and carotid sinus baroreceptors and cardiopulmonary

Question 32

What is the end goal of extrinsic peripheral blood flow?

Answer 32

arterial pressure regulation

Question 33

What is the most important mechanism for acute blood pressure control?

Answer 33

the arterial baroreceptor reflex

Question 34

In the arterial baroreceptor reflex, what does an increase in blood pressure cause?

Answer 34

increase stretch, increase in afferent traffic, decrease in sympathetic output, and therefore vasodilation

Question 35

In the arterial baroreceptor reflex, what does an decrease in blood pressure cause?

Answer 35

decrease stretch, decreased afferent traffic, decreased sympathetic output, and therefore vasoconstriction

Question 36

What does chronic stimulation of the arterial baroreceptor reflex cause?

Answer 36

a decrease in receptor sensitivity

Question 37

What is the blood pressure range for maximum firing of the arterial baroreceptor reflex?

Answer 37

180-200 mmHg

Question 38

What is the blood pressure range for no stimulation of the arterial baroreceptor reflex?

Answer 38

50-60 mmHg

Question 39

What are the hormonal vasoconstrictor agents involved in controlling blood pressure?

Answer 39

epinephrine, norepinephrine, angiotensin II, vasopresin

Question 40

What are hormonal vasodilator agents involved in controlling blood pressure?

Answer 40

natriuretic peptides and 'various agents'

Question 41

How does epinephrine work in skeletal and cardiac muscle?

Answer 41

it is a mild vasodilator

Question 42

When are hormonal vasodilator agents released?

Answer 42

in response to stretch

Question 43

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

Answer 43

by regulating blood volume because it is a potent vasoconstrictor

Question 44

What does angiotensin II cause in regards to the renal system (why is this important, I have no idea)?

Answer 44

it causes salt and water retention due to the aldosterone release from the adrenal glands

Question 45

How does the renal-body fluid mechanism work in response to high blood pressure?

Answer 45

there is a direct increase in renal output of Na and water which decreases extracellular fluid retention and blood volume to lower blood pressure

Question 46

How does the renal-body fluid mechanism work in response to low blood pressure?

Answer 46

it decreases renal output of Na and water which causes fluid retention and increased blood pressure

Question 47

What are short term mechanisms that regulate arterial blood pressure in response to an acute change in pressure?

Answer 47

baroreceptors, chemoreceptors, CNS ischemic response, Renin-Angiotensin vasoconstriction

Question 48

What is the long term mechanism that regulates arterial blood pressure in response to an acute change in blood pressure?

Answer 48

Renin-blood volume pressure control

Question 49

Where are atrial and coronary baroreceptors located

Answer 49

located in carotid sinus

Question 50

What is the function of atrial and coronary baroreceptors?

Answer 50

respond to vessel stretch and deformation caused by increase in blood pressure; inhibits sympathetic output which leads to lower blood pressure

Question 51

What type of baroreceptors are cardiopulmonary baroreceptors?

Answer 51

low pressure receptors

Question 52

What do cardiopulmonary baroreceptors respond to?

Answer 52

a decrease in volume