Determinants of MAP Flashcards

1
Q

regulation of MAP?

A

arteriolar resistance

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2
Q

prehypertension?

A

120-139

80-99

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3
Q

stage 1 HTN?

A

140-159

90-99

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4
Q

stage 2 HTN?

A

greater 160

greater 100

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5
Q

BP regulation?

A

short term - neural

long term - endocrine/paracrine

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6
Q

sympathetic effects?

A

increased vasoconstriction - increased TPR

increased HR and SV (increased CO)

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7
Q

pressor effect?

A

NE - generalized vasoconstriction

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8
Q

alpha1

A

vasoconstriction

NE, E

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9
Q

beta2

A

vasodilation

E preferentially

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10
Q

exercising skeletal muscle

A

autoregulation dominates (vasodilation)

as opposed to resting muscle - vasoconstrictor neural control dominates

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11
Q

parasympathetic effect on MAP?

A

indirect vasodilation
decrease HR
some decrease in contractility (SV)

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12
Q

high P baroreceptors

A

carotid sinus and aortic arch
-increased P, increased stretch
-increased firing rate
graded response**

most responsive to change in pressure vs. simply a sustained pressure

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13
Q

increased high P baroreceptor firing rate?

A

increased MAP

and vice versa for decrease in firing rate

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14
Q

pulse pressure?

A

baroreceptors greater response to greater PP
-firing rate decrease with decreased PP

increased MAP with decreased PP

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15
Q

end-result of high P baroreceptor?

A

vasodilation and bradycardia

  • increased MAP
  • increased stretch
  • decreased sympathetic output
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16
Q

high P baroreceptor and vasodilation?

A
increased stretch
increased firing rate
inhibits vasomotor area
decreased sympathetic
decreased vasoconstriction
increased vasodilation***
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17
Q

high P baroreceptor and HR?

A
increased stretch
increased firing rate
excitation of cardioinhibitory area
increased parasympathetic
decreased heart rate***
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18
Q

increased baroreceptor firing?

A

decreased sympathetic output and increased parasympathetic output

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19
Q

low-P baroreceptors?

A

in cardiac chambers and large pulmonary vessels
-involved in blood volume regulation

increased firing rate with increased stretch

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20
Q

A fibers?

A

low P baroreceptors

-monitor HR

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21
Q

B fibers?

A

low P baroreceptors
-monitor atrial volume

impacted by CVP

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22
Q

activation of low P receptors?

A
increased VR
increased stretch
increased firing rate
increased heart rate
decreased renal vasoconstriction
increased renal blood flow
decreased effective circulating volume
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23
Q

bainbridge reflex?

A

increased VR and RAP > increased HR

conterbalance to high P baroreceptor

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24
Q

low P baroreceptors?

A

renal vasodilation!

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25
Q

at high volume

A

bainbridge reflex > increased heart rate

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26
Q

at low volume

A

baroreceptor reflex > increased heart rate

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27
Q

volume loading?

A

bainbridge dominant

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28
Q

volume depletion?

A

high P baroreceptor dominant

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29
Q

peripheral chemoreceptors?

A

carotid body and aortic body

PO2 (at low levels), PCO2 and pH changes

  • regulates respiration
  • some influence on cardiovascular system
30
Q

central chemoreceptors?

A

medulla oblongata

PCO2 and pH changes

31
Q

increased PCO2, decreased pH?

A

increased vasoconstriction

increased TPR

32
Q

decreased PCO2, increased pH?

A

decreased vasoconstriction

decreased TPR

33
Q

chemoreceptors and HR?

A

integrated physiologic response

  • increases the rate of ventilation
  • inhibits cardioinhibitory centers
  • increase in HR, TPR, and MAP

tachycardia and vasoconstriction***

34
Q

balance between chemoreceptor and baroreceptors?

A

if activated together:

  • decreased MAP, increased CO2
  • increased chemoreceptors, decreased baroreceptors
  • vasoconstriction

if activated separataely:
increased MAP, increased CO2
-increased chemoreceptors, increased baroreceptors
-baroreceptor mediated inhibition dominates

35
Q

vasoconstrictors

A
Epi (a1)
serotonin
ANG II
AVP
endothelin
36
Q

vasodilators

A
Epi (B2)
histamine
ANP
bradykinins
PGE2, PGI2
NO
37
Q

ANG II

A

converted from ANG I by ACE

  • mainly in lungs**
  • stimulated by increased renin
  • released during blood loss or exercise

vasoconstrictor

38
Q

what stimulates renin release?

A

dropped renal BP

39
Q

ADH/AVP

A

aka vasopressin
posterior pituitary gland
-vasocontrictor

released during hemorrhagic shock

40
Q

histamine

A

released with tissue damage

-vasodilator

41
Q

ANP

A

atrial myocytes release with increased stretch

-vasodilator

42
Q

kidney

A

key organ for long-term blood volume regulation

Na+ and H2O secretion

43
Q

decreased kidney blood pressure?

A

leads to decreased GFR and decreased urine volume

44
Q

humoral regulation of BP?

A

RAAS
ADH/AVP
ANH/ANP

45
Q

RAAS

A

increases Na+ reabsorption (water follows)

-increased ECF volume and MAP

46
Q

renal juxtaglomerular apparatus?

A

macula densa cells detect Na+ in distal tubules

-secrete renin with low levels

47
Q

angiotensinogen?

A

inactive form
-renin converts angiotensinogen to ANG I

ANG I > ANG II when comes in contact with ACE

results in thirst, vasoconstriction, vasopressin

48
Q

ANG II

A
vasoconstriction
adrenal gland aldosterone
stimulates vasopressin
stimulates thirst
stimulates Na+ reabsorption
stimulates SNS activity
49
Q

aldosterone

A

stimulated by ANG II

promotes renal Na+ reabsorption

50
Q

ADH/AVP

A

vasoconstrictor
-stimulated by hypothalamus

increases water reabsorption in kidneys

  • distal tubules and collecting duct aquaporins
  • increases MAP***
51
Q

vasopressin

A

antidiuretic hormone

-decreased urine output

52
Q

ANP

A

vasodilator

  • get rid of Na+ (natriuresis)
  • released by atrial cells
  • increased stretch - ANP release

opposes RAAS

decreased ECF volume and MAP

53
Q

intermediate response?

A

RAAS

54
Q

respiratory system and MAP?

A

decreased thoracic P > more VR
water evaporation
ventilation - affects chemoreceptor response

55
Q

liver and MAP?

A

hematocrit and protein content

starling forces

56
Q

GI and urinary and MAP?

A

long term BP regulation

-electrolyte and H2O

57
Q

endocrine and MAP

A

blood volume and vascular tone

58
Q

temperature and MAP?

A

skin blood flow

sweating is fluid loss

59
Q

orthostasis

A

gravity affects

  • hypotension
  • increased VR - muscle pump

response is baroreceptor reflex

60
Q

vasovagal syncope

A

emotional stress
-dramatic parasympathetic response

bradycardia, hypotension, apnea

decreased MAP - failed baroreceptor response

61
Q

fight or flight

A

increased sympathetic response

  • increased skeletal muscle blood flow (beta2)
  • vaso and venoconstriction (alpha1) renal and splanchnic

increased CO

increase blood volume

net increase MAP

62
Q

exercise

A

early and delayed response

central and local control
-overall decrease in TPR**

63
Q

early exercise response?

A

hypothalamus
-increased HR and contractility

early vasoconstriction to inactive tissues

64
Q

delayed exercise response?

A

mechanical:
pump of muscles, increased VR (increased SV)

chemical:
local metabolites increasing flow to working muscles
-causes decreased TPR

65
Q

exercising muscle?

A

increased capillary hydrostatic pressure
increased O2 delivery
increased O2 consumption

66
Q

6 changes with exercise?

A

exercise pressor reflex
-sustain sympathetic outflow

arterial baroreflexes
-reset so sympathetic output continues with increased MAP

vasodilation (local)

epinephrine (beta1 and beta2)

increased venous return (muscle pump)

temperature regulation

67
Q

noticeable changes with exercise?

A

increased MAP

  • SBP > DBP due to increased CO
  • increased PP

decreased TPR***
-vasodilation in working muscles

68
Q

training

A

greater O2 extraction
increased capillary, oxidative enzymes, mitochondria, and myoglobin

lower resting HR
greater SV
lower TPR

69
Q

endurance training

A

increased LV volume (no change in wall thickness)

-increased filling

70
Q

resistance training

A

increased LV wall thickness

-hypertrophy

71
Q

hemorrhagic shock?

A

high P baroreceptor reflex dominates with volume depletion

increased vasopressin (increased vasoconstriction)
decreased ANP (decreased vasodilation)

increased PCO2 - increased chemoreceptor firing
-integrated response increase HR and vasoconstriction

72
Q

survive hemorrhage?

A

die of kidney failure

-renal ischemia