Blood Vessels and BP (Part 2) Flashcards


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1

T/F: Nervous control of blood flow is primarily autonomic control and is mostly parasympathetic, which controls circulation (vasoconstriction primarily)

False

2

What does the parasympathetic do to the heart?

decrease HR and slight decrease in contractility

3

Sympathetic innervate all vessels except:

Capillaries, precapillary sphincters, and some metarterioles

4

T/F: Innervation of small arteries and arterioles allow sympathetic nerves to increase vascular compliance

False

5

T/F: Large veins and the heart are sympathetically innervated

True

6

Neurons from this area excite preganglionic vasoconstricot neurons in the SNS; CNS ischemic response

Vasoconstrictor area

7

Neurons from this area project upward and inhibit the vasoconstrictor area

Vasodilator area

8

Which area receives signals from the circulatory system and output signals control vasodilator and vasoconstrictor areas?

Sensory area

9

T/F: Heart control has sympathetic control via the cardioinhibitory area and parasympathetic control via the vasoconstrictor area

False

10

T/F: Higher nervous system control can excite or inhibit the vasomotor area

True

11

How does the baroreceptor reflex work?

Senses changes in BP and sends signal to CNS which initiates appropriate response to maintain nearly constant BP

12

Baroreceptors maintain MAP within ___-____ mm Hg

85-100 mm Hg

13

T/F: Baroreceptor reflex maintains moment to moment control of BP and is not related to tissue needs, similar to autoregulation.

False

14

Where are the nerve endings of baroreceptors located?

Arterial wall, in aortic arch and carotid sinus

15

Which bundle of baroreceptor nerve endings are more important for BP regulation because they are more sensitive?

Carotid sinus receptor

16

T/F: Baroreceptor activation inhibits the vasomotor center

True

17

What is the effect of inhibiting the vasomotor center?

Brain reduces sympathetic outflow in order to bring BP down

18

What does it mean for baroreceptors to reset?

If BP goes up and stays up, baroreceptors will establish a new baseline and maintain this higher average BP

19

Describe the pathway of baroreceptor activation due to high BP

  1. High BP stimulates baroreceptors in carotid sinus/aortic arch
  2. Cardioinhibitry center stimulated
  3. Decrease sympathetic impulses to heart
  4. Decrease rate of vasomotor impulses (allows vasodilation)
  5. Decrease CO and R
  6. BP returns to normal range
20

Describe the pathway of baroreceptor activation due to low BP

  1. Low BP inhibits baroreceptor
  2. decreased impulse from baroreceptor = cardioacceleratory center activated
  3. Increase sympathetic impulses to heart
  4. Vasomotor fibers stimulated (causes vasoconstriction)
  5. Increase CO and R = return BP to normal
21

What is the chemoreceptor reflex?

Sensing O2 lac, CO2 excess, or H+ ion excess and stimulate vasomotor center

22

T/F: Cerebral ischemia or impaired lung function can activate the baroreceptor reflex mechanism

False

23

Where are peripheral chemoreceptors located?

Carotid and aortic bodies

24

Where are central chemoreceptors located?

Medullary neurons

25

T/F: Chemoreceptor drive is significantly increased in HTN

True

26

Chemoreceptors are not stimulated until P falls below _____ mm Hg

80 mm Hg

27

T/F: Chemoreceptor activation increases sympathetic activity

True

28

What is the CNS ischemic response?

Reduced cerebral BF causes CO2 buildup which stimulates vasomotor center, thereby increasing atrial P

29

T/F: CNS ischemic response is one of the most powerful activators of the sympathetic vasoconstrictor system

True

30

CNS ischemic response is activated when P falls below ______, with greatest activation at ____-_____ mm Hg

60; 15-20 mm Hg

31

What does α1 innervate?

  • Vascular smooth muscle
  • Heart
  • Liver
  • intestinal smooth muscle
32

What does α2 innervate?

  • Vascular smooth muscle
  • Brain
  • Pancreatic cells
33

What does β1 innervate?

  • Heart
  • JG cells in kidney
34

What does β2 innervate?

  • Skeletal muscle
  • Vascular and bronchial smooth muscle
  • Uterus, liver, GI, urinary tract, ocular smooth muscle
35

When is epinephrine or norepinephrine released?

During fight/flight response

36

How do α1 receptors respond to E or NE?

Primary vasoconstriction of blood vessels

37

How do α2 receptors respond to E or NE?

  • Minor vasoconstriction of blood vessels
  • Inhibition of NE release (brain)
  • Inhibition of renin release (kidney)
38

How do β1 receptors respond to E or NE?

  • Cardiac stimulation (positive chrono., dromo., inotropic)
  • Renin release (kidney)
39

How do β2 receptors respond to E or NE?

Smooth muscle relaxation causing vasodilation and bronchodilation

40

T/F: β2 activation increases Ca2+ resulting in vasoconstriction

False

41

T/F: Both the SA node and the AV node contain β2 receptors

False

42

Increased rate of SA and AV node firing = positive ___________ effect

Chronotropic

43

Which adrenergic receptor protects the heart from free-radical mediated damage by compensating for lost β1 contractility?

α1

44

List vasoconstricting agents

  1. NE and E
  2. Angiotensin
  3. Vasopressin
  4. Endothelin
45

List vasodilator agents

  1. Bradykinin
  2. Serotonin
  3. Histamine
  4. Prostaglandins
  5. NO
46

Describe the mechanism of bradykinin-mediated vasodilation (via β2)

β2 on endothelial cells --> PLC --> IP3 --> ↑Ca --> ↑NO -->cGMP/PKG in SMC -->↑MLCP --> Relaxation

Alternatively: ↑Ca --> PLA -cox-> PGI2 --> IP receptor on vascular SMC --> cAMP/PKA --> ↓MLCK --> Relaxation

47

Increased P causing excretion of water is known as:

P diuresis

48

Increased P causing excretion of salt is known as:

P natriuresis

49

T/F: RAAS ↑ water and sodium retention and ↓ vasoconstriction

False

50

Ang II binds to ________ receptors on vascular SMCs, causing vasoconstriction

AT 1 (Gq)

51

How does Ang II affect NE release and reuptake?

Increases release, decreases reuptake

52

What are the main functions of vasopressin?

  • Enhances water reabsorption via V2 receptor (Gq)
  • Moderate vasoconstriction via V1 receptor (Gq) on SMCs
53

What are the main functions of Aldosterone?

  • Mineralocorticoid
  • Causes Na retention and K excretion from kidney