Boron Cardiac Physio Review Flashcards

1
Q

resistance in series

A

R + R + R

blood flow in given organ

  • single artery supplies organ
  • goes to ateries > arterioles > capillaries > veins
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2
Q

resistance in parallel

A

1/R + 1/R + 1/R

systemic circulation
-arteries that branch off aorta to organs

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3
Q

three kinds of pressure in circulation

A

1 driving pressure - axial
2 transmural pressure - radial - intravascular vs. tissue pressure
3 hydrostatic pressure - gravity on column of fluid

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4
Q

CO = ?

A

HR x SV

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5
Q

poiseuilles law

A

flow = deltaP x r^4 / 8nl

r  = radius
n = viscosity
l = length of vessel

flow directly proportional to pressure difference and inversely to radius of vessel to the fourth and inversely to length and viscosity

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6
Q

reynolds number

A

determines when blood flow becomes turbulent

  • laminar below 2000
  • turbulent above 3000
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7
Q

increases in reynolds number

A

**more turbulent flow

decreased blood viscosity - decreased hematocrit, anemia

increased blood velocity - narrow vessel

also increased vessel diameter

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8
Q

pulse pressure

A

difference between SBP and DBP

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9
Q

four factors generating presure in circulation

A

1 - gravity
2 - compliance of vessels
3 - viscous resistance
4 - inertia

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10
Q

gravity

A

P difference when difference in height

-ex/ when patient standing

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11
Q

standing pressure

A

high in feet
reference at heart
low in head

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12
Q

driving pressure when standing?

A

remains the same in head and heart

  • difference between SBP and DBP
  • slightly higher at heart
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13
Q

gravity does not affect

A

driving pressure that governs flow

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14
Q

palpatory method of BP

A

radial artery at wrist

-systolic ONLY

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15
Q

auscultatory method of BP

A

systolic and diastolic

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16
Q

fick principle

A

allows you to measure CO

CO = O2 consumption / O2 arteries - O2 veins

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17
Q

highest cross sectional area

A

capillaries

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18
Q

slowest velocity of blood

A

capillaries

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19
Q

blood volume distribution

A

20% systemic arterial
65% systemic venous
10% pulmonary
5% heart chambers

20
Q

arteries

A

resistance vessels

21
Q

veins

A

volume reservoirs

-capacitance vessels

22
Q

compliance

A

distensibility of blood vessels
-greater in veins (if low pressure)

-change in volume with change in pressure

23
Q

veins at “arterial pressure”

A

not as compliant
-sudden increase in volume leads to large increase in transmural pressure

case with saphenous vein in CABG

24
Q

transmural pressure

A

distending force - increases circumference of vessel

25
Q

laplaces law

A

describe how tension in vessel wall increases with transmural pressure

-for given transmural pressure - wall tension gets larger as radius increases

26
Q

convection

A

main mechanism for net transfer of fluid across capillary membrane

determined by hydrostatic pressure and colloid osmotic pressure

starling equation used

27
Q

standing

A

increased capillary pressure - due to increased hydrostatic forces

-results in edema

28
Q

pulmonary edema

A

pulmonary HTN - increased hyrostatic pressure

-with left-sided heart failure

29
Q

nephrotic syndrome

A

loss of protein

-decreased plasma colloid oncotic pressure - edema

30
Q

pregnancy

A

plasma protein synthesis too slow

-decreased plasma colloid oncotic pressure - edema

31
Q

during ischemia

A

blood vessels deteriorate

-with reperfusion - local edema

32
Q

lymph flow

A

dependent on interstitial pressure

33
Q

slow APs

A

SA and AV nodes

34
Q

fast APs

A

atrial myocytes
purkinje fibers
ventricular myocytes

35
Q

phase 0

A

upstroke

  • Ca slow
  • Na and Ca fast
36
Q

phase 1

A

rapid repolarization

  • inactivation of Na and Ca
  • activaiton of K
37
Q

phase 2

A

plateau phase

-Ca and Na

38
Q

Phase 3

A

repolarization

-K

39
Q

Phase 4

A

electrical diastolic phase

  • most negative - maxi diastolic potential
  • SA, AV nodes - changes in K, Ca, and F currents
  • produce pacemaker activity
40
Q

If

A

non-selective cation channels

41
Q

SA node phase 4

A

outward K
inward I-f
slight inward Ca

42
Q

SA node phase 0

A

depolarization

-calcium

43
Q

three ways to slow SA node

A
  • decrease phase 4 steepness
  • max diastolic potential more negative
  • threshold more positive
44
Q

acetylcholine on SA and AV nodes

A

PS activity
-slows pacemaker - all three mechanisms

1 - decreases If - reduces phase 4 steepness
2 - opens GIRK channels - increasing K conductance - making maximum diastolic potential more negative
3 - reduces I-Ca in SA node - reduces steepness of phase 4 and moves threshold more positive

45
Q

ACh on AV node

A

not usually the pacemaker
-PS innervation slows conduction velocity

-inhibition of I-Ca that makes threshold more positive

46
Q

sympathetics on heart

A

increase heart rate

  • increase I-f in nodal cells - increase phase 4 steepness
  • increase I-Ca - steepens phase 4 depolarization and makes threshold more negative

**no large change in maximum diastolic potential

47
Q

sympathetics in heart muscle

A

atria and ventricles

  • positive inotropic - contraction
  • 4 ways

1 - increased I-Ca - more Ca in muscle cell - greater Ca induced Ca release
2 - increase sensitivity of SR Ca release channel to cytoplasmic Ca
3 - enhance Ca pumping into SR - stimulate SERCA Ca pump
4 - increased I-Ca presents more Ca to SERCA - so SR Ca stores increase over time

**all more Ca to troponin C - more forceful contraction