Circulation And Hemodynamics Flashcards

1
Q

What is the site of the highest resistance and largest drop is pressure?

A

Arterioles

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2
Q

Composition of capillaries

A

Single layer of endothelial cells surrounded by basal lamina

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3
Q

How is perfusion of capillaries determined?

A

By metabolic needs of the tissue and the tone of the arteriolar smooth muscle

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4
Q

Velocity of blood flow

A

V=Q/A
Speed at which blood travels

Flow=speed and number of blood traveling

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5
Q

Flow equation

A

DeltaP/R

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6
Q

Poiseuille’s law

A

(8ln)/(piR^4)

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7
Q

Series resistance

A

Resistance is the sum of the forces

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8
Q

Parallel resistance

A

Resistance is 1/sum of the resistances and is lower than all individual resistances

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9
Q

Bruits

A

Heard when turbulent flow occurs in an artery or other vascular channel

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10
Q

Reynold’s number

A

Nr=(pdv)/n

Density
Diameter
Velocity
Viscosity

<2000 predicts laminar flow while >2000 predicts turbulent flow

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11
Q

Mean arterial pressure

A

2/3 DBP + 1/3 SBP

DBP + 1/3 pulse pressure

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12
Q

Arteriosclerosis

A

Plaque deposits form in arterial walls - decreases diameter and compliance of vessels, increases SBP, pulse pressure, and MAP (no large influence on DBP)

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13
Q

Lipid soluble microcirculation

A

O2, CO2. Driven by partial pressure gradient for that gas - also determined by the surface area of capillaries.

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14
Q

Water soluble microcirculation

A

Ions, glucose, AA
Diffusion doesn’t occur well. Limited movement between clefts of endothelial cells. Limits SA available for movement of molecules.

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15
Q

Osmosis of microcirculation

A

V important.

Driven by hydrostatic and osmotic pressure differences btwn lumen of vessel and interstitial space

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16
Q

Proteins in microcirculation

A

Generally don’t cross except in kidney and intestine where fenestrations in the capillaries will allow for limited movement of protein molecules

17
Q

Starling equation

A

IV=Kf [(Pc-Pi)-(piC-piI)]

18
Q

Kf

A

Determines magnitude of fluid movement

19
Q

Pc

A

Favors filtration based on fluid pressure

Hydrostatic capillary pressure

20
Q

Pi

A

Opposes filtration

Hydrostatic interstitial pressure

21
Q

PiC

A

Opposes filtration

Capillary oncotic pressure

22
Q

PiI

A

Favors filtration

Interstitial oncotic pressure

23
Q

How will Pc impact lymph filtration

A

Pc can increase with venous pressure, heart failure, and ECF volume expansion and will cause an increase in lymph filtration

24
Q

How will piC impact lymph filtration

A

piC will decrease from decrease plasma protein concentration, severe liver failure, protein malnutrition, or nephrotic syndrome and this will increase lymph filtration

25
Q

How will Kf impact lymph filtration

A

Kf will be increase by burns or inflammation and will increase the lymph filtration

26
Q

How does impaired lymphatic drainage affect lymph filtration?

A

It will increase it

Can be caused by standing for long periods, removal or LNs, and parasitic infections

27
Q

Active hyperemia

A

Blood flow is proportional to metabolic activity I.e. blood flow is increased to exercising SKM

28
Q

Reactive hyperemia

A

An increase in blood flow in reaction to a period of decreased blood flow

29
Q

Myogenic hypothesis

A

Can explain autoregulation - states if vascular SM is stretched it will react and contract

30
Q

Metabolic hypothesis

A

O2 delivery is matched to O2 consumption

31
Q

local metabolic control is most important for which types of circulation

A

Coronary, cerebral, pulmonary, renal, and SKM when exercising

32
Q

Sympathetic control is most important for which types of circulation

A

SKM at rest and skin circulation

33
Q

Mechanisms for generating heat

A
Thyroid hormones (stimulate Na/K+ and increase metabolic rate)
Sympathetic nervous system, shivering (started by posterior hypothalamus)
34
Q

Mechanisms for dissipating heat

A

Coordinated by anterior hypothalamus to decrease symp outflow through arterioles and shunt blood to venous plexuses near surface of skin

Also increase sympathetic cholinergic activation of sweat glands