ANS Regulation of the Cardiovascular System

Question 1

Afferent

Answer 1

transmits sensory information from peripheral organs to the CNS

Question 2

Efferent

Answer 2

carry motor information away from the peripheral nervous system to the muscles, heart, blood vessels, and glands

Question 3

Somatic

Answer 3

ACh/Nicotinic receptor (skeletal muscle)

Question 4

Sympathetic

Answer 4

ACh/Nicotinic receptor –> Norepinephrine/alpha1, 2, beta1, 2 adrenergic receptors

Question 5

alpha1 g-coupled + norepinephrine

Answer 5

vasoconstriction

Question 6

alpha2 g-coupled + norepinephrine

Answer 6

auto-inhibitory

Question 7

beta1 g-coupled + norepinephrine

Answer 7

heart (increase in heart rate and stroke volume)

Question 8

beta2 g-coupled + norepinephrine

Answer 8

vasodilation

Question 9

Parasympathetic

Answer 9

ACh/Nicotinic Receptor –> ACh/Muscarinic Receptor

Question 10

Sympathetic/Adrenal

Answer 10

ACh/Nicotinic Receptor –> Adrenal Medulla –> Epinephrine (80%) and Norepinephrine (20%)

Question 11

Sympathetic Nervous System helps us

Answer 11

handle life’s stresses: hemorrhage, exercise, or even a change in posture

Question 12

Parasympathetic Nervous System helps us

Answer 12

conserve and store energy

Question 13

Anatomy (sympathetic)

Answer 13

thoraco-lumbar

Question 14

Anatomy (parasympathetic)

Answer 14

cranio-sacral

Question 15

Sympathetic functions

Answer 15

dilate pupils, dilate bronchioles, increase HR and SV, release adrenaline/epinephrine, stop digestion, delay emptying colon and bladder, stress: fight or flight

Question 16

Parasympathetic functions

Answer 16

constrict pupils, constrict bronchioles, decrease HR, promote digestion, empty colon and bladder, rest and recovery

Question 17

Atropine blocks

Answer 17

muscarinic receptors

Question 18

propanolol blocks

Answer 18

beta1 receptors

Question 19

Vagus dominates at

Answer 19

rests

Question 20

sympathetic dominates during

Answer 20

exercise

Question 21

Parasympathetic changes in HR are

Answer 21

fast

Question 22

Sympathetic changes are

Answer 22

slower, increase rate of depolarization

Question 23

Sympathetic postganglionic fibers

Answer 23

NE released onto beta1 adrenergic receptors: HR^

Question 24

Parasympathetic (vagus) postganglionic fibers

Answer 24

release ACh onto muscarinic receptor: HR decreases

Question 25

Sympathetic dominates

Answer 25

during exercise

Question 26

Parasympathetic dominates

Answer 26

at rest

Question 27

Sympathetic innervation of blood vessels

Answer 27

lots

Question 28

Parasympathetic innervation to blood vessels

Answer 28

very little

Question 29

Sympathetic on heart and blood vessels

Answer 29

Cause large increase in HR and SV because increase rate, contractility, relaxation, conduction velocity Increase in TPR (increase in arterial constriction), and decrease in compliance (increase in venous constriction)

Question 30

Parasympathetic on heart and blood vessels

Answer 30

Cause large decrease in HR due to decrease in rate and conduction velocity Little change to blood vessels because little change to arterial and venous constriction

Question 31

Sympathetic: stress

Answer 31

increase HR, SV --> increase CO ensure blood flow to heart and brain regulates heart rate during exercise innervates blood vessels throughout the body

Question 32

Parasympathetic: recovery

Answer 32

rest and relaxation: decrease HR Promotes digestion Regulates HR at rest Primarily vagus (heart); limited blood vessel innervation

Question 33

Negative feedback control for humans

Answer 33

Control of mean arterial blood pressure

Question 34

Two advantages of using a negative feedback control system for mean blood pressure

Answer 34

if CV system starts to fail can compensate, can fix a disturbance

Question 35

Cut the baroreceptor nerves

Answer 35

brainstem does not know the real blood pressure

Question 36

R = set point

Answer 36

= 100 mmHg

Question 37

G = cardiovascular system

Answer 37

= heart, arteries and arterioles, veins and venules

Question 38

H = baroreceptors

Answer 38

= carotid sinus and aortic = afferent nerves

Question 39

D = disturbance

Answer 39

= hemorrhage, exercise

Question 40

Pa = mean arterial pressure

Answer 40

try to keep at 100 mmHg

Question 41

Between MAP and receptor firing rate around 100 mmHg (zone of maximal sensitivity)

Answer 41

Linear relationship

Question 42

Baroreceptors are

Answer 42

stretch receptors, when MAP ^, the afferent nerve firing ^

Question 43

With no baroreflex (open loop)

Answer 43

H = 0, deltaPa = deltaD

Question 44

Linear, time-invariant system, look at changes in Pa

Answer 44

Pa = (D/(1+GH)) + ((RG)/(1+GH))

Question 45

If no disturbance

Answer 45

deltaD = 0

Question 46

If there is no change in our set point or th cardiovascular system

Answer 46

delta(RG) = 0

Question 47

If we get rid of our feedback system (cut the baroreceptor nerves --> open loop)

Answer 47

H = 0

Question 48

Arterial pressure (Pa) decreases

Answer 48

decrease in baroreceptor nerve firing

Question 49

decrease in baroreceptor firing

Answer 49

e>0

Question 50

e>0

Answer 50

increase in sympathetic firing, decrease in parasympathetic firing

Question 51

increase in sympathetic firing

Answer 51

increase in HR, SV, TPR, decrease in Cv

Question 52

Decrease in parasympathetic firing

Answer 52

increase in HR

Question 53

Increase in HR, SV, TPR, decrease in Cv

Answer 53

Increase in CO = HR*SV

Question 54

Increase in CO = HR*SV

Answer 54

Increase in arterial pressure (Pa = CO*TPR)

Question 55

Control the carotid sinus pressure (CSP)

Answer 55

independently of the mean arterial pressure (MAP)

Question 56

Open loop:

Answer 56

the carotid sinus is surgically isolated, CSP does not equal Pa

Question 57

Open loop math

Answer 57

GH = -deltaPa/deltaCSP GH = -output/input GH = slope

Question 58

When CSP is very low

Answer 58

Pa increases

Question 59

When CSP is very high

Answer 59

Pa decreases

Question 60

Sympathetic firing increase

Answer 60

Increase in HR, SV, CO, TPR, PA, decrease in Cv --> handle stress, fight or flight

Question 61

Parasympathetic firing increase

Answer 61

Decrease in HR, CO, Pa, tidal volume, increase in digestion --> rest and recovery

Question 62

Reflexive (respond to a change in MAP)

Answer 62

gravity, mild exercise

Question 63

Anticipatory (prevent a change in MAP)

Answer 63

exercise, long term adjustments (pregnancy)

Question 64

Gravitational changes cause blood to pool in the legs

Answer 64

reduces carotid sinus pressure, activates the baroreflex, HR increases and constrict blood vessels (Cv decreases) --> increase in CO and TPR and therefore Pa

Question 65

What happens to a swimmer's heart rate in the "head down" position prior to a race

Answer 65

Pressure at carotid baroreceptors increases when we put our head down (due to gravity), firing of baroreceptor nerves increases, brainstem measures pressure as too high and sympathetic firing decreases --> HR and Blood pressure decreases

Question 66

Baroreceptors reduce

Answer 66

variability of the blood pressure -- no effect on MAP

Question 67

We have maximum baroreceptor sensitivity near

Answer 67

normal arterial pressure

Question 68

What happens with hypertension?

Answer 68

Decrease sensitivity (would not respond as well to postural changes, hemorrhage, etc), instead our body adapts to the higher pressure so that we can maintain our sensitivity

Question 69

With hypertension

Answer 69

curve shifts to the right

Question 70

Long term blood pressure control involves

Answer 70

hormones (ADH, aldosterone, ANG II), kidney --> gain = infinity deltaPa = 0

Question 71

After a heart transplant, which of the following are true?

Answer 71

Circulating epinephrine increases HR by activating beta1 receptors