Hemodynamics, Systemic Circulation Flashcards by Matt Stanton

structure of aorta

lots of elastic fiber

largest wall thickness

How well did you know this?

Not at all

Perfectly

precapillary sphincter vs arteriole?

sphincter has a thicker wall

How well did you know this?

Not at all

Perfectly

composition of capillary?

just endothelial cells

venules are also only endothelial cells**

How well did you know this?

Not at all

Perfectly

arteries

thick elastic walls

serve as pressure reservoir

How well did you know this?

Not at all

Perfectly

veins

serve as blood reservoir

How well did you know this?

Not at all

Perfectly

arterioles

resistance vessels

can contract smooth vessels to increase resistance

How well did you know this?

Not at all

Perfectly

capillaries

site of exchange

How well did you know this?

Not at all

Perfectly

where is most of blood volume

systemic greater than pulmonary

How well did you know this?

Not at all

Perfectly

veins

volume reservoir

2nd reserve is pulmonary circulation

How well did you know this?

Not at all

Perfectly

immediate blood loss?

veins are a reservoir

How well did you know this?

Not at all

Perfectly

most of volume where?

systemic veins

How well did you know this?

Not at all

Perfectly

where is blood pressure highest?

at the aorta

How well did you know this?

Not at all

Perfectly

where is greatest pressure drop?

at the level of the arterioles

resistance vessels

How well did you know this?

Not at all

Perfectly

arteries and BP?

maintain the MAP

How well did you know this?

Not at all

Perfectly

mean arterial pressure

driving force for blood flow
pressure gradient

must be maintained to ensure adequate blood supply

How well did you know this?

Not at all

Perfectly

auscultatory BP?

SBP

DBP

How well did you know this?

Not at all

Perfectly

palpatory BP?

SBP

How well did you know this?

Not at all

Perfectly

systolic pressure

higher

How well did you know this?

Not at all

Perfectly

diastolic pressure

lower

How well did you know this?

Not at all

Perfectly

korotkoff sounds

turbulent flow that is heard when measuring a blood pressure

How well did you know this?

Not at all

Perfectly

how to approximate mean pressure in arteries?

time spent in diastole is greater**

MAP = DBP + 1/3 PP

PP is difference between systolic and diastolic

MAP = DBP + 1/3 (SBP - DBP)

How well did you know this?

Not at all

Perfectly

what happens during exercise with mean pressure?

spend less time in diastole than at rest

MAP = DBP + 1/2 (SBP - DBP)

How well did you know this?

Not at all

Perfectly

where is blood pressure when standing the highest?

dorsalis pedis

How well did you know this?

Not at all

Perfectly

effect of gravity on blood pressure?

when standing

hydrostatic pressure increases
you have a fluid column

much greater pressure at level of the feet

decreased pressure as you go above the heart

*this is important when going from supine to standing and the pooling in the veins due to the greater pressure
you become light headed

How well did you know this?

Not at all

Perfectly

cross sectional area?

greatest at the capillaries

velocity of flow?

slowest at capillaries

aorta CSA?

greatest diameter, smallest CSA

blood flow rate?

L/min volume of blood per unit time equal for ALL segments

fick principle

indirect method to determine blood flow based on total O2 consumption and difference between arterial and venous O2 content

fick principle equation?

CO = oxygen consumption / arterial - venous O2 Q = VO2 / A - V O2 difference

blood flow velocity?

mm/sec highest in aorta lowest in capillaries

flow velocity?

flow velocity = flow / cross sectional area

laminar flow

silent

turbulent flow

produces murmurs

reynolds number?

threshold from where you transition from silent flow to turbulent flow

what can cause increased turbulent flow?

* *increase in velocity of blood flow - local decrease in diameter increased diameter decreased viscosity

which vessel would likely first develop turbulent flow in an anemic patient?

????

C = deltaV / deltaP

compliance?

given change in pressure, what is the change in volume

systemic veins?

20x more compliant serve as major blood reservoir

effect of aging on pulse pressure

compliance of vessels decreased and an increase in pulse pressure

compliant artery?

smaller pulse pressure vs a stiffer artery

LaPlace's Law

wall stress -effect of pressure, radius, wall thickness T ~ P x r / 2h

LaPlace and BP?

2x radius has to withstand 2x wall tension

greatest wall tension?

aorta

arteries and wall tension?

fibrous bands reinforce to protect against aneurysm

damage or reduction of elastic fibers?

vessels enlarge - aneurysm

driving force for blood flow?

pressure gradient

flow = ?

Flow = pressure gradient / resistance

CO = ?

MAP / TPR TPR - total peripheral resistance CO = Q = cardiac output = flow

Ohm's Law =?

I = V/R

flow regulation?

by resistance not enough blood to supply entire body alter the resistance

in series?

flow is equal at all points adding resistance always increases overall resistance total resistance always greater than any one individual

in parallel?

flow can be independently regulated adding resistance in parallel decreases overall resistance total resistance always less than any one individual

what does parallel allow?

allows for regulation of flow distribution while maintaining MAP obesity - adds in parallel, decreasing TPR, necessitating increased CO to maintain MAP

where is adequate flow always required?

brain and heart

flow?

inversely proportional to resistance

Poiseuille's law

radius is key determinant to resistance increased radius decrease resistance increase flow

blood flow is proportional to what?

directly to radius to 4th power directly to pressure gradient inversely to vessel length and blood viscosity

anemia?

decreases viscosity, increases flow

polycythemia?

increases viscosity, decreases flow

two ways to control resistance to flow?

extrinsic - neural, endocrine intrinsic -

biggest influence on resistance?

sympathetic influence

vasoconstriction?

alpha-1 receptors

vasodilation?

beta-2 receptors

endocrine/paracrine influence?

influence vascular tone

key for extrinsic regulation of TPR?

total peripheral resistance sympathetic nervous system - alpha 1 receptors - norepinephrine or epinephrine promotes vasoconstriction

example of extrinsic control

orthostatic hypertension

intrinsic control?

matching blood flow to tissues need | mediated by local factors on arteriolar smooth muscle

autoregulation

flow independent of blood pressure flow proportional to tissue metabolism flow independent of nervous reflexes cerebral, coronary, skeletal muscle, renal tissues