blood pressure I

Question 1

what is pressure? what is MAP?

Answer 1

-P = flow x resistance
-MAP = CO x resistance
CO maintained so variation comes from resistance
CO =SV x HR

Question 2

what is the dicrotic notch related to?

Answer 2

-the closure of the aortic valve and separation of Peripheral circ and heart

Question 3

what does the diastolic run off refer to?

Answer 3

• the drop in pressure due to blood flowing down stream

- pressure in periphery

Question 4

what does vasoconstricition do to MAP and Capillary pressure? vasodilation?

Answer 4

vasoconstriction- increases MAP and decreases capillary pressure
vasodilation- decreases MAP and increases capillary pressure

Question 5

how do you calculate the MAP

Answer 5

1/3 (systolic bp - diastolic bp) +DBP

Question 6

pulse pressure- what is it and what’s it related to? what can it be used for?

Answer 6

pulse pressure is a pressure wave that travels faster than blood and is generated by the BP
related to stroke volume output, cardiac compliance, systolic ejection
-it can be used to measure the compliance in the pt heart and vessels by measuring the velocity

Question 7

what does a fast velocity in pulse pressure suggest?

Answer 7

-it means that there is some lack of compliance because a more compliant vessel absorbs the force of the pulse pressure

Question 8

where is pulse wave amplification the greatest and why?

Answer 8

• it is greatest downstream (near abdominal ao where there’s the bifurcation) because of the reflection of the wave back up the Ao

Question 9

what does it tell us if the augmented pressure (combo of forward and reflected waves) is higher?

Answer 9

-there is less aortic compliance and could be pathological

Question 10

what are two ways that we can regulate blood flow- acutely and long-term

Answer 10

acute- vasoconstriction and dilation

long-term- change size of vessels and number

Question 11

how do you myogenically maintain autoregulation

Answer 11

• stretch on vessel will elicit contraction

Question 12

what is NO and what does it do

how are capillaries affected?

Answer 12

• nitric oxide- alters the contraction in SM and causes vasodilation
• capillaries ARE NOT affected b/c they don’t have SM

Question 13

endothelin

Answer 13

-vasoconstrictor- acts on endothelin receptor of SM and acts to constrict SM

Question 14

how are acute and long-term regulatory mechanisms of blood pressure different?

Answer 14

1) acute- seconds to days, changes RESISTANCE, ANS changes thru reflexes
2) long term- days to weeks, changes VOLUME, has renal mechanisms, neurohormonal mechs

Question 15

what do sympathetics do to blood vessels, heart, kidneys, adrenals to regulate blood pressure?

Answer 15

blood vessels- vasoconstriction via alpha receptors
heart- increase contractility via beta rec
kidneys-decrease glomular filtration rate (vasoconst), renin release
adrenals-epi./norepi release

Question 16

what do parasympathetics do in terms of regulating blood pressure

Answer 16

-decrease HR via action on SA and AV nodes

Question 17

when sympathetics cause vasoconstriction, what occurs in the arterioles and veins

Answer 17

• increases pressure in arterioles and increased vascular resistance and decreased flow thru tissue
• veins- increase venous return to the heart and increase heart pumping blood into periphery