Exam #2: Blood Pressure Regulation Flashcards Preview

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Flashcards in Exam #2: Blood Pressure Regulation Deck (39):
1

What is blood pressure?

Force exerted by the blood against any unit area of the vessel wall

Proportional to Flow x resistance

2

What is the equation for mean arterial pressure?

MAP= CO x TRP

Cardiac output x total peripheral resistance

3

Draw the arterial pressure waveform.

N/A

4

What is the effect of vasoconstriction?

Increased MAP
Longer DBP (Diastolic runoff) & shallower
Decreased capillary hydrostatic pressure pressure (because constriction is occurring upstream of the capillary, in the arteriole)

5

What is the effect of vasodilation?

Decreased MAP
Shortened DBP (Diastolic runoff) & steeper
Increased capillary hydrostatic pressure

6

What is pulse pressure?

SBP- DBP

Systolic blood pressure - diastolic blood pressure

7

How is MAP estimated?

(1/3 x Pulse pressure) + DBP

8

Review how blood pressure is measured.

1) Cuff inflation & listen to turbulent flow of blood through artery
2) Korotkoff sounds

- Not as accurate as direct cannulation

9

What are the determinants of pulse pressure? How are these augmented pathologically?

Stroke volume output
- PDA
- Aortic regurgitation

Compliance
- Arteriosclerosis
- Aortic stenosis

Systolic ejection

10

Does is pulse wave velocity measured clinically?

Compliance; the pulse wave is inversely proportional to compliance

Slow= compliant
Fast= rigid

11

As the pulse wave travels down the blood vessel, what happens to the amplitude of the wave?

It gets bigger i.e. it is "amplified" thus, downstream pressure are greater than proximal pressures ?????

12

What does rigidity i.e. reduced compliance do to the amplitude of the pulse wave?

Intensifies it i.e. a larger amplitude= a less compliant aorta

13

What happens to the incisura as you compare arterial waveforms, traveling distally through the vascular tree?

The incisura occurs later in time

("Blip" that occurs from closure of aortic valve)

14

What happens to the arterial waveform in regards to the amplitude as you travel down the vascular tree?

Dampen

Especially at the level of the arterioles

15

Why is it good to have large pressure drop-off at the level of the arterioles?

Protection of the capillaries distally

16

What happens to capillary hydrostatic pressure, resistance, & blood velocity (in the capillaries) with constriction of the arterioles?

Decreased capillary hydrostatic pressure
Increased resistance
Decreased blood velocity

17

What happens to capillary hydrostatic pressure, resistance, & blood velocity (in the capillaries) with dilation of the arterioles?

Increased capillary hydrostatic pressure
Decreased resistance
Increased blood velocity

18

Describe the distribution of CO at rest.

High percentage of cardiac output goes to:
1) Liver
2) Kidney
3) Muscles
4) Brain

19

What changes the distribution of cardiac output?

Demand

20

How is the distribution of cardiac output changed?

Local changes in arteriole resistance

21

What is autoregulation?

Maintenance of a stable blood flow, despite increasing arterial pressure

22

What are the mechanisms of autoregulation?

Metabolic mechanism
Myogenic mechanism

23

If there is an increase in pressure, what has to happen to resistance to maintain flow?

Increased resistance

24

What is EDRF?

Nitric Oxide

25

What is the effect of NO on arterioles?

Vasodilation

26

Describe the NO mechanism of action.

Inhibition of MLCK & activation of MLCP

27

Describe the bradykinin mechanism of action.

asdf

28

What is the effect of endothelin?

Vasoconstriction

29

Describe the mechanism of action of endothelin.

Inhibition of MLCP

30

List some other vasoconstrictors.

NE
Angiotensin II
Vasoppressin

31

List the characteristics of short-term (acute) regulation of blood pressure.

- Minutes to seconds
- Change in resistance
- ANS reflex

32

List the characteristics of long-term regulation of blood pressure.

- Days to weeks
- Involves changes in volume
- Renal & hormonal mechanisms

33

What is the effect of sympathetic stimulation of the blood vessels? What is the receptor?

Vasoconstriction
alpha adrenergic recptor

34

What is the effect of sympathetic stimulation of the heart? What is the receptor?

Increased contractility, HR, & conduction velocity
Beta adrenergic receptor

35

What is the effect of sympathetic stimulation of the kidneys? What is the receptor?

Renin release (vasoconstriction via Angiotensin II)
Decreased GFR (via vasoconstriction)
Beta adrenergic receptor

36

What is the effect of sympathetic stimulation of the adrenal gland?

Epinephrine & NE release

37

What is the effect of PNS stimulation of the heart?

Muscarinic activation in SA & AV nodes leads to decreased HR

38

When the SNS is stimulated, where is there going to be the greatest change in vascular resistance? Where will the lowest change in vascular resistance be?

Greatest= cutaneous
Smallest= renal

39

What is the effect of vasoconstriction of the arterioles? What is the effect of vasoconstriction of the veins? What is the net effect?

Arterioles= Increased vascular resistance, leading to decreased flow through tissue (more time for metabolism to occur)

Veins= increased venous return to heart

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