Fluid Shift across the capillary wall and systemic oedema

Question 1

what acts as the go between the blood and body cells?

Answer 1

interstitial fluid

Question 2

how many layers of endothelial cells are there in capillaries?

Answer 2

1

Question 3

f’s: capillaries

Answer 3

allow rapid exchange of gases, water and solutes with interstitial fluid
delivery of O2 and nutrients to the cells
removal of metabolites from cells

Question 4

What is BF in capillaries dependent of?

Answer 4

the contractile state of the arterioles

Question 5

f: terminal arterioles?

Answer 5

regulate regional BF to the capillary bed CB in most tissues

Question 6

f: precapillary sphincters

Answer 6

regulate flow in a few tissues eg mesentery

Question 7

why is the BF in CB v slow?

Answer 7

to allow time for exchange

Question 8

what is formed when capillaries unite?

Answer 8

venules

Question 9

How are exchangeable proteins moved across the capillary wall?

Answer 9

via vesicular transport

Question 10

How do lipid soluble substances pass across the capillary wall?

Answer 10

via endothelial cells

Question 11

How do plasma proteins move across the capillary wall?

Answer 11

they don’t

Question 12

How do small water soluble substances pass across the capillary wall?

Answer 12

across pores

Question 13

What does fluid movement follow?

Answer 13

pressure gradient

Question 14

What does the movement of gases and solutes follow?

Answer 14

Fick’s Law of diffusion

Question 15

What is transcapillary fluid flow passively driven by?

Answer 15

pressure gradients across the capillary wall

Question 16

d: ultra-filtration

Answer 16

filtration using a medium fine enough to retain colloidal particles, viruses, or large molecules

Question 17

What is net filtration pressure (NFP) directly proportional to? What is the coeffient?

Answer 17

forces favouring filtration-forces opposing filtration
Filtration coefficient (Kf)

Question 18

Name the forces favouring filtration?

Answer 18

capillary hydrostatic pressure

interstitial fluid osmotic pressure

Question 19

Name the forces opposing filtration?

Answer 19

capillary osmotic pressure

interstitial fluid hydrostatic pressure

Question 20

What is the equation for NFP?

Answer 20

(PC + pi i)-(pi C + Pi)

Question 21

What can be concluded from NFP quation?

Answer 21

starling forces favour filtration at arteriolar end, reabsorption at end of venular end

Question 22

What is the general name given for the forces involved in transcapillary flow?

Answer 22

starling forces

Question 23

Name the major forces favouring filtration in systemic transcapillary flow?

Answer 23

Pc capillary hydrostatic pressure

Question 24

Name the major forces opposing filtration in systemic transcapillary flow?

Answer 24

Pi C capillary osmotic pressure

Question 25

How is the excess fluid returned to the circulation?

Answer 25

via lymph system as lymph

Question 26

what is the value of pulmonary osmotic pressure?

Answer 26

25mmHg

Question 27

what prevents accumulation of interstitial fluid?

Answer 27

efficient lymphatic drainage

Question 28

d: oedema

Answer 28

Accumulation of fluid in interstitial space

Question 29

what is the effect of oedema in the lungs?

Answer 29

diffusion distance increases gas exchange is therefore compromised

Question 30

Name the causes of oedema

Answer 30

raised capillary pressure
reduced plasma osmotic pressure
lympathetic insufficiency
changes in capillary permeability

Question 31

How does raised capillary pressure occur?

Answer 31

arteriolar dilatation

raised venous pressure

Question 32

What is the effect of left ventricular failure?

Answer 32

pulmonary oedema

Question 33

What is the effect of right ventricular failure?

Answer 33

peripheral oedema, ankle/ sacral

Question 34

If you have a oedema and stand for a long time what can be caused?

Answer 34

swollen ankles

Question 35

How does reduced plasma osmotic pressure occur?

Answer 35

Normal [plasma protein]p = 65-80 g/l
Oedema if < ~ 30 g/l
normal plasma protein falls if
malnurished
proetin malabsorption
XS renal excretion of protein
hepatic failure

Question 36

how does lymphatic insufficiency occur?

Answer 36

lymph node damage filariasis-elephantiasis

Question 37

How do changes in capillary permeability occur?

Answer 37

inflammation

histamine increases leakage of protein

Question 38

what is a clinical sign of pulmonary oedema?

Answer 38

breathlessness

Question 39

On examination how will pulmonary oedema be manifested?

Answer 39

crepitations in auscultation of lung bases

Question 40

How will pulmonary oedema be demonstrated in CXR?

Answer 40

haziness in perihilar region