Brainscape's Knowledge GenomeTM

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


See full index

physiology > CVS > Flashcards

CVS Flashcards

1
Q

Why does increase in sympathetic activity decrease filtration?

A

Increases pre cap & post cap resistance ratio–> decreases mean capillary pressure–> decreases filtration

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

Why does exercise increase filtration?

A
  1. Increases sympathetic tone
  2. Increases local metabolites-
    a. Relaxes pre cap sphincters
    b. Decreases basal myogenic tone
    c. Increases osmolality of interesting fluid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mechanism of increased filtration in LVF vs. hypoproteinemia

A

LVF- increased pulmonary hydrostatic pressure

Hypoproteinemia- decreased osmotic pressure

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

What is the mechanism of filtration and absorption at the capillaries?

A

Filtration: Capillary pressure at arteriolar end(37)> osmotic pressure
Absorption: osmotic pressure>capillary pressure(15)

Osmotic pressure = mean capillary pressure= 25mmHg

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

How does lipid solubility affect diffusion across capillaries?

A

Lipid soluble substances can diffuse through whole capillary-greater surface area
Lipid insoluble substances-intercellular pores

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

How does molecular weight affect diffusion & what is the range of weights

A

Increase in MW decreases diffusion- 10000–>60,000

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

Why is micropinocytosis an impt component of teams capillary exchange?

A

Allows passages of macromolecules like alpha globulin

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

What is the mechanism of edema?

A
  1. Increase in capillary pressure,
  2. decrease in osmotic pressure, 3.deposition of osmotically active substances in interstium,
  3. Lymphatic obstruction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does velocity affect diffusion across a capillary?

A

Increased v- decreases time for exchange

Decreased- decreases flow for exchange

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

Why is velocity low in capillaries and high in aorta?

A

Velocity=flow/cross sec area

Cross sec area increases from aorta to capillaries, therefore velocity decreases

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

Why does increased cross sectional area of capillaries optimise exchange?

A

Increased CSA-decreased velocity-more effective exchange

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

Why can turbulent flow occur in aorta?

A

CSA of aorta less than capillaries-increased velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why is a cardiac flow murmur heard in anaemia at the aorta?

A

Murmurs are caused by turbulent flow. Turbulent flow occurs Reynolds number>2000
Reynolds number= diametervelocitydensity/viscosity
Aorta-high velocity & anaemia causes decreased viscosity

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

Why are murmurs heard in severe stenosis?

A

Turbulent flow in vessels due to high velocity of blood

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

Why is laminar flow in systemic circulation more advantageous than turbulent flow?

A

More resistance in turbulent flow

Turbulent flow more likely to develop thrombi

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

How does atherosclerosis affect type of flow of blood?

A

Reduces Reynolds number- laminar flow

17
Q

Why are the organs supplied with parallel branches off of the aorta?

A

Resistors in parallel decrease total resistance, therefore total systemic resistance is less

18
Q

How do tissues ensure nutrient delivery via blood?

A

Regulate tone of arterioles-intrinsic regulation

19
Q

Why does arteriolar vasodilation cause mean arterial pressure (MAP) to plummet?

A

Arterioles- primary resistors

Vasodilation- decreased resistance-decreases upstream pressure (MAP) and increases downstream pressure

20
Q

Why do factors which cause vasoconstriction result in an increased MAP?

A

Vasoconstrictors-decrease radius-increase resistance of arterioles-increase upstream pressure (MAP) and decrease downstream pressure

21
Q

What factors contribute to vasoconstriction?

A

NE from sympathetic post ganglionic neurons
Epinephrine from adrenal medulla
Angiotensin 2 via AT1 receptor
ADH via V1 receptor

22
Q

What factors cause vasodilation of arterioles?

A

Decreased sympathetic activity
Epi via B2 receptors
NO from endothelium
Metabolites-carbon dioxide, protons, potassium, adenosine

23
Q

Why does NE from post ganglionic sympathetic neurons cause vasoconstriction of arterioles?

A

NE-alpha-1 receptors-Gq-increased cytosolic calcium in sm cells-tonic effect on skeletal muscles & cutaneous muscles at rest, splanchnic & renal at stress

24
Q

As an aneurysm enlarges why is it more likely to burst?

A

Pressure remains the same then by Laplace law wall tension=P*radius. As radius increases, wall tension increases to maintain pressure-aorta bursts-eg. Subarachnoid haemorrhage, aortic aneurysm

25
Q

Why is a dissecting aneurysm a life threatening condition?

A

Systemic arterial disease-damage to endothelial lining-blood flows between & dissects layers of aorta-weakens wall of aorta-bursts

26
Q

Why is a dilated heart inefficient?

A

By Laplace law, wall tension=P*radius. As radius increases, increased wall tension is required-increased oxygen demand

27
Q

Why do veins contain 70% of the blood volume and are the major reservoirs of blood?

A

Compliance resides in the venous system.

Compliance is how easily a vessel is stretched.

28
Q

If CO fell, what would happen to VR & vice versa?

A

Proportional decrease

29
Q

Why does increase in blood volume increase VR?

A

VR represents vascular function-directly proportional to pressure gradient-right atrial pressure(downstream p) & mean systemic filling pressure(upstream p)

Mean systemic filling pressure directly proportional to blood volume

30
Q

Why does an increase in compliance cause a decrease in VR?

A

VR-depends on pressure gradient between RAP & Mean systemic filling pressure-Msfp is inversely proportional to compliance

31
Q

When a person goes from a supine to upright posture why does pressure and volume in dependent veins increase?

A

Higher pressures in vessels below the level of heart due to gravity. Higher pressures in veins-increases compliance-pooling of blood

32
Q

When a person goes from supine to upright posture why can MAP fall?

A

Increased pressure in dependent veins-increased compliance-pooling of blood-decreased VR-no compensation, decreased SV-decreased MAP

33
Q

When a person goes from upright to supine posture what compensatory mechanisms act to prevent fall in MAP?

A

Cardiopulmonary receptors (stretch receptors)-in great veins, heart & pulmonary artery-decreased preload-afferents inhibit parasympathetic & stimulate sympathetics-arteriolar & venoconstriction, increase hr

Arterial baroreceptors-reflex changes

34
Q

Why do patients have to be positioned in trendelberg position when inserting a line in internal jugular vein/subclavian vein?

A

Pressure above heart is sub atmospheric- punctured vein may introduce an air embolus-patients positioned so deep veins of upper extremity are below the level of heart

35
Q

Why is sphygmomanometer placed at level of heart?

A

For accurate reading, above the heart pressure falls due to gravity and below heart pressure increases due to gravity

36
Q

Why does orthostatic intolerance occur?

A

Reduced vascular volume, venodilators, poor ventricular function, dysautonomias-decrease VR + decreased VR due to increased venous compliance due to effect of gravity

physiology (4 decks)

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