Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Cardio > Regulation of arteriolar resistance > Flashcards

Regulation of arteriolar resistance Flashcards

1
Q

What is the main way of assessing someones blood pressure/resistance?

A

Auscultation of Korotkoff sounds

Using Shphygmomanometer & stethoscope

This is used in General practice and in hospital settings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does Ausculation of Korotkoff sounds work?

A

Cuff around the arm gets very tight, and releases pressure gradually

At different parts of the cardiac cycle, blood will be able to ‘overcome and push through’ the pressure exerted by the cuff

The sounds that are heard, indicate the pressure at which blood can overcome the pressure, thus give an indication of BP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What sounds can be heard during Korotkoff testing, and what causes each sound?

A

Silence:
- pressure exerted by the cuff is higher than any part of the cycle ∴ no flow ∴ no noise

Tapping:
- pressure in cuff is only overcome during strongest part of systole ∴ flow only permitted for V short period

Thumping:
- Large part of the cycle overcomes cuff’s pressure ∴ longer period of flow ∴ more thumpy than tappy

Muffled:
- Pretty much all the cycle exerts pressure > cuff so only short periods when there is no flow

Silence 2:
- Whole cycle overcomes the cuff ∴ no gaps in the noise ∴ effectively silent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the advantages of Korotkoff auscultation?

A

Non-invasive

Cheap

Quick

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the dis-advantages of Korotkoff auscultation?

A

Not very accurate

Discontinuous

Needs care

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do elastic arteries contribute to smooth blood flow?

A

They stretch & recoil with heart contraction

This makes them act as a pressure reservoir

∴ they dampen down pressure variations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When are elastic arteries most stretched?

A

Ventricular systole (contraction)

Pressure is highest ∴ they expand outwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What other feature in the CVS means elastic arteries can maintain higher blood pressure/flow during diastole?

A

Valves

These prevent back-flow when the elastic arteries recoil, so they squeeze the blood in the ‘forward’ direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Although elastic arteries dampen pressure variations, the pressure curve/wave is affected by various factors

What factors affect the arterial pressure curve?

A
  • stroke volume
  • velocity of ejection
  • total peripheral resistance

(+ elasticity of the arteries - as mentioned previously)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is normal arterial pressure?

A

120/80 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does arterial pressure change as you get older?

A

Increases with age

Systolic (pulse) pressure increases especially

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the shape of the pressure wave/curve

A

Kinda bell shaped

  • Rising side is steeper than the falling side
  • Small upwards blip on falling (right) side due to AORTIC VALVE CLOSING
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

“The maximum point on the arterial pressure wave gives ________”

A

Systolic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

“The minimum point on the arterial pressure wave gives __________”

A

Diastolic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is MAP?

Is it useful?

A

Mean arterial pressure

Useful in general indications of health, however it is useful to give systolic / diastolic instead as you can identify specific problems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

At what time of the day is arterial pressure lowest?

A

Night (when asleep)

17
Q

What can cause arterial pressure to naturally rise?

A

Pain

Stress

Exercise

Shaggin

Stimulant drugs

18
Q

Where in the body is highest average blood pressure achieved?

A

Main (elastic) Arteries

19
Q

Where in the body is the maximum blood pressure achieved?

A

Left ventricle during systole

highly variable ∴ not highest on average

20
Q

Where is average blood pressure lowest?

A

Veins & venules

21
Q

Where is the lowest blood pressure achieved?

A

Right atrium during diastole

22
Q

How does pressure decrease through the vascular tree?

A

Small drop through arteries (95-90 mmHg)

Large drop through arterioles (90-40 mmHg)
- “Resistance vessels”

In capillary bed (40-20 mmHg)

In returning venules & veins (20-5 mmHg)

23
Q

How is the pulmonary circulation pressure different to the systemic in terms of pressure?

A

Pulmonary circ is about 1/5th of the systemic’s pressure

24
Q

“Blood velocity is related to _____________ and is highest in ___________ and lowest in _________”

A

Cross sectional area of vessel’s lumen

Highest velocity in Aorta & vena cava

Lowest velocity in Capillaries

25
Q

Why does gravity affect venous flow so much?

A

Low pressure

Vessels are distensible, collapsable and just a bit floppy really

26
Q

How does gravity affect the pressure values in veins in different parts of the body?

A

Subtracts about 40 mmHg in pressure from the head area:

  • Lying down = 10 mmHg
  • Standing = -30 mmHg

Adds about 80 mmHg to pressure at the feet:

  • Lying down = 10 mmHg
  • Standing up = 90 mmHg
27
Q

Summarise the effect of gravity on the CVS, and describe how this is clinically useful

A

Does not affect driving pressure from arteries to veins

Causes venous distension in legs:

  • Decreases EDV, preload, SV, CO, MAP
  • orthostatic (postural) hypotension

Causes venous collapse in neck:
- Height of venous collapse can be used to estimate central venous pressure

28
Q

Why is it important to flex your thigh and calf muscles if you are static and upright for long periods of time?

A

Low blood flow to head can cause syncope (hot guardsmen)

Risk of deep vein thrombosis

Risk of varicose vein development

Flexing skeletal muscle ‘pumps’ the blood so this is avoided

29
Q

Summarise what factors affect blood flow in veins

A

Gravity

Skeletal muscle pump

Respiratory pump

Venomotor tone

Systemic filling pressure

30
Q

Highlight the 2 main stages in clotting

A

Formation of platelet plug

Formation of fibrin clot

31
Q

What chemical is central in converting fibrinogen to fibrin?

A

Thrombin

32
Q

How does the epithelium prevent clot formation?

A

Stops blood contacting collagen
- no platelet aggregation

Produces prostacyclin and NO
- both inhibit platelet aggregation

Produces tissue factor pathway inhibitor (TFPI)
- stops thrombin production

Expresses thrombomodulin
- binds thrombin & inactivates it

Expresses heparin
- also inactivates thrombin

Secretes tissue plasminogen activator (t-PA)
- plasminogen plasmin & digests clot

33
Q

What does Kortokoff tapping tell you?

A

Systolic pressure

34
Q

What does Kortokoff silence (2) tell you?

A

Diastolic pressure

Cardio (41 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions