Brainscape's Knowledge GenomeTM

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


See full index

Body Systems > L14 Capillary Exchange > Flashcards

L14 Capillary Exchange Flashcards

1
Q

what is capillary hydrostatic pressure

A

required to exchange substances/fluids across cap network
(aka allows capillary exchange)

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

how is capillary structure adapted to be able to exchange

A

> short diffusion distance
- thin walls (1micrometer)
- small diameter (8micrometers) -> RBC all go in single file through it, and have direct contact with wall
- close proximity
- decreases diff distance, therefore diff time

> blood flows slowly
- due to large cross sectional area (largest area of all vessels)
- large surface area for exchange
= 10+ billion capillaries
- ~600square metres

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

what is the 3 types of capillaries

A

> continuouse - most caps

> fenestrated
(have water filled pores) - in endorcrine organs, intestine, kidneys

> sinusoid
(large clefts between endothelial cells and incomplete BM)
- free exchange of water and larger solutes eg plasma proteins

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

during substance exchange across cap walls, what molecules move out into cells and what moves in into caps (down pressure and conc gradients)

A

OUT=
water
O2
AAs
Glucose
Ions

IN=
water
CO2
waste molecules
ions

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

what are the 3 principle transport mehcanisms in cap exchange

A

> diffusion
- through endothelaial cell membrane, ion cannels, or clefts/pores

> bulk flow
- through clefts/pores
- down pressure gradient by filtration/osmosis

> transcytosis
- vesicular transport

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

what are the routes that substances can DIFFUSE via and what are they

A

through endothelial membrane:
- lipid soluble gases & moelcules
- eg O2 CO2 fatty acids

through channels
- ions
- eg Na+ Ca2+ etc

between endothelial cells (water filled pores)
- small water soluble molecules
- eg glucose urea AAs

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

what are the routes that substances can travel via transcytosis via and what are they?

A

in vesicles through the endothelial cell
larger macro molecules eg glycoproteins, insulin

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

what are the routes that substances can travel thtough bulk flow via and what are they

A

through clefts/pores
moving down pressure gradients
water soluble molecules only - e.g. water, ion, nutrients, waste

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

what’s it called when things move into the cap lumen via bulk flow

A

reabsorption

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

what’s it called when things move into the interstial fluid via bulk flow

A

filtration

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

what is bulk flow determined by

A

the net pressure difference across cap walls

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

what 4 forces influence fluid and solute movement

A

capillary hydrostatic pressure
interstitial fluid hydrostatic pressure
blood colloid osmotic pressure
interstitial fuid colloid osmotic pressure

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

what is cap hydrostatic pressure

A

the BP exerted on cap walls pushing fluid out

decreases along capillary

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

what is interstitial fluid hydrostatic pressure

A

the presssure exerted on outer cap wall by the IF, pushing fluid in

generally negligable (~0mmHg)

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

what is blood colloid osmotic pressure

A

the plasma osmotic pressure pulling fluid into caps

affected by blood volume

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

what is interstitial fluid colloid osmotic pressure

A

osmotic pressure of interstitial fluid pulling fluid out

generally negligable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is net filtration pressure

A

determines whether fluid moves in or out of cap

NFP = net hydrostatic pressure - net osmotic pressure

NHP = cap hydrostatic pressure (CHP) - interstitial fluid hydrostatic pressure (IHP)

NOP = blood colloid osmotic pressure (BCOP) - interstitial fluid colloid osmotic pressure (ICOP)

18
Q

if CHP>BCOP

A

+ve NFP
so filtration occurs

19
Q

if BCOP>CHP

A

-ve NFP
reabsorption

20
Q

what is the mmHg range the CHP goes through along the cap

A

35 - 18mmHg

due to resistance the blood faces as it moves along

21
Q

what is the mmHg range the BCOP goes through along the cap

A

trick question heh
BCOP is constant
cuz the pressure is formed by plasma proteins which dont move cuz theyre too big

so the pressure stays around 25mmHg along the cap

22
Q

what is the consequence of the max filtration pressure being greater than the max absorption pressure?

A

the point where they cross over at equilibrium is towards the venous end
this means for filtration takes place than absortpion

see onenote

23
Q

on average how much fluid is filtrated a day trhough caps in L

A

24L/day

24
Q

on avg how much fluid absorbed a day through caos in L

A

20.4 L/day

25
Q

what could be an effect of high BP of NFP

A

CHP rises
so NFP rises

incerased filtration
fluid collects in extremities
systemic oedema

26
Q

effect of haemorrage on NFP

A

CHP decreases
NFP decreases

favours reabsorption
increases BP & cardiac outpput (to compensate for blood loss)

27
Q

effect of dehyrdration on NFP

A

reduction in blood volume = more conc of plasma proteins

so higher BCOP

so NFP decreases

increased reabsorptions
so fluid taken up from tissue into blood stream (to delay onset of symptoms)

28
Q

effect of tissue damage (eg sprained ankle) on NFP

A

ICOP drops - cuz caps are more leaky and plasma proteins escape into interstiitial fluid

NFP increases

so filtration increases

local swelling around area (oedema)

29
Q

in pulmonary circulation, how is blood flow adapted to engance O2 absorption compared to other organs

A

other organs vessels dilate when O2 falls to enhance O2 absoprtion

in lungs, arterioles contrict in regions of low O2 to shunt blood flow to O2 rich areas

30
Q

how in the pulmonary circulation is it adapted so that gas wxchange occurs constantly

A

pulmonary vascular resistance is very low
- arterioles are shorter, wider and have thinner walls

CHP is lower than in systemic
(10mmHG compared to 35 mmHg)
- this is caused by the much lowere resistence mentioned before

arteries are more distensible (expandable)
- so any increase in cardiac output can be accomodated without too much increase in pressure

31
Q

what is the CHP to BCOP relationship like along the whole vessel in the pulmonary circulation

A

CHP (10) < BCOP (25) along whole cap length

which means fluid absorbed along the whole cap length

32
Q

in pulmonary circulation, what would happen is the CHP exceeded 25mmHg

A

fluid starts leaking into alveoli
pulmonary oedema
no good

33
Q

how does the coronary circulation differ from systemic in terms of blood flow

A

when everywehere else the release of adrenaline causes vasoconstriction

in the coronary arteries, it’ll promote vasodilation
because of beta adrenergic receptors (see L13)

34
Q

how does coronary blood flow get affected by the cardiac cycke

A

during ventricular systole, the left coronary artery acc get cut off and flow is restricted

blood flow much faster in diastole

see onenote for diagram

35
Q

what happens to compensate for the shut off in blood spply during systole in the cardiac vessels

A

cardiomyocytes have very high O2 reserves

the myocardium has high cap density - so increases O2 extraction

caps have few arterial collaterals* (unsure what this is) - so blood flow moves more efficiantly

36
Q

in cerebral circulation, what occurs when theres vasoconstriction in the periphery

A

vasodilation of the cerebral vessels

must ensure blood flow presereved always

37
Q

how much cardiac output does the brain consume and why is this odd

A

well its not odd, it makes sense cuz it needs more blood

but it consumes 12% or CO for its 2% body mass

38
Q

what is the flow rate in the brain

A

750ml/min

39
Q

unlike cardiomyocytes, why do neurons need sm O2

A

they have poor metabolic reserves

so they need constant flow of O2, cant survive on their own

40
Q

how many arteries supply the brain

A

4
then they anastomose inside the cranium

Body Systems (21 decks)

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