Fluid shift across capillary wall

Question 1

What % of weight is body water?

Answer 1

60% of body weight

Question 2

What proportion of body water is extracellular?

Answer 2

1/3rd

Question 3

What percentage of body water is interstitial?

Answer 3

75%

Question 4

What is the function of interstitial fluid?

Answer 4

acts as the go-between blood and body cells

Question 5

What is the roll of capillaries in terms of metabolites?

Answer 5

remove metabolites from cells

Question 6

What does blood flow in the capillaries depends upon?

Answer 6

the contractile state of the arterioles

Question 7

In which tissue are precapillary sphincters present?

Answer 7

mesentery

Question 8

What is the rate of blood flow through the capillary bed?

Answer 8

slow (like a lake)

Question 9

What do capillaries unite to form?

Answer 9

Venule

Question 10

How do water soluble substances pass through capillaries?

Answer 10

through water filled capillary pores

Question 11

How do lipid soluble substances pass through capillaries?

Answer 11

gasses can pass through endothelial cells

Question 12

How are exchangeable proteins moved across the capillary walls?

Answer 12

vesicular transport

Question 13

How do plasma proteins pass across capillary walls?

Answer 13

They can’t

Question 14

What gradient does fluid follow?

Answer 14

Pressure gradient

Question 15

What gradient do gasses and solutes follow?

Answer 15

Fick’s law of diffusion

Question 16

What is transcapillary flow driven by?

Answer 16

Pressure gradients

Question 17

What is ultra-filtration?

Answer 17

exchange of protein-free plasma across capillary walls

Question 18

What are the forces favouring filtration?

Answer 18

capillary hydrostatic pressure (Pc) interstitial fluid osmotic pressure (πi)

Question 19

What are the forces opposing filtration?

Answer 19

capillary osmotic pressure (πc)

Interstitial fluid hydrostatic pressure (Pi)

Question 20

What is the normal value for Pc?

Answer 20

35mmHg at arteriolar end

17mmHg at venular end

Question 21

What is the normal value for πi?

Answer 21

1mmHg

Question 22

What is the normal value for πc?

Answer 22

25mmHg

Question 23

What is the normal value for Pi?

Answer 23

1mmHg

Question 24

Where to starling forces favour absorption and filtration?

Answer 24

Favour filtration at the arteriolar end

Absorption at the venular end

Question 25

How is excess fluid returned to the circulation?

Answer 25

Via the lymphatics as lymph

Question 26

What is pulmonary resistance in comparison to systemic resistance?

Answer 26

10%

Question 27

What is pulmonary capillary hydrostatic pressure?

Answer 27

Low (8-11mmHg)

Question 28

What is capillary osmotic pressure?

Answer 28

25mmHg

Question 29

Why is lymphatic drainage so important?

Answer 29

Prevents accumulation of interstitial fluid

Question 30

What is oedema?

Answer 30

Accumulation of fluid in the interstitial space

Question 31

What factors are affected by pulmonary oedema?

Answer 31

Diffusion distance increases so gas exchange is compromised Compliance is affected

Question 32

What are the causes of oedema?

Answer 32

Raised capillary pressure Reduced plasma oncotic pressure Lymphatic insufficiency Changes in capillary permeability LVF

Question 33

What are the causes of raised venous pressure?

Answer 33

Left ventricular failure (pulmonary oedema) Right ventricular failure (peripheral oedema, sacral) Prolonged standing (swollen ankles- damage the valves in the lower limb veins)

Question 34

What will heart failure do to the frank starling curve? and why?

Answer 34

Shift it right you will have less stroke volume per pre-load, causing pooling of blood in the heart and creating back-pressure

Question 35

What is the normal plasma protein pressure?

Answer 35

65-80g/l

Question 36

What are the causes of raised capillary pressure?

Answer 36

arteriolar dilatation raised venous pressure

Question 37

When does reduced plasma protein cause oedema?

Answer 37

When it is \<30g/l

Question 38

What are the causes of reduced plasma oncotic pressure?

Answer 38

Malnutrition Protein malabsorption Excessive renal excretion of protein (proteinuria) Hepatic failure (liver is not manufacturing proteins in the first place)

Question 39

What are the causes of lymphatic insufficiency?

Answer 39

Lymph node damage Filariasis-elephantiasis

Question 40

What kind of oedema will lymphatic deficiency cause?

Answer 40

Non-pitting oedema

Question 41

What are the causes of change in capillary permeability?

Answer 41

Inflammation (histamine increases leakage of proteins)

Question 42

What is the pathogenesis of LVF in oedema?

Answer 42

accumulation of fluid in the interstisital and intra-alveolar lung spaces, manifested by varying degrees of SOB.

Question 43

What are the clinical manifestations of LVF?

Answer 43

Clinically there may be crepitation’s in auscultation of lung bases. chest x ray shows haziness in perihilar region