L14

Question 1

What characteristics of the capillary make perfect for two way exchanged?

Answer 1

• Steep conc gradient
• Short distance diffusion pathway
• Slow blood flow
• large surface area

Question 2

What are the three type of capillaries?

Answer 2

• Continuous =
• Fenestrated = Contains pores allow allow exchange of WATER and solutes
• Sinusoidal = Large clefts and incomplete basement membrane, allows exchange of WATER and LARGE SOLUTES

Question 3

Forces in the capillary that affect blood flow?(4)

Answer 3

• Capillary hydrostatic pressure
• Interstitial hydrostatic pressure
• Blood colloid osmotic pressure
• interstitial fluid COLLOID osmotic pressure

Question 4

What is Capillary hydrostatic pressure in terms of what it does it to the fluid in capillaries?

Answer 4

• blood pressure exerting on pushing fluid out

Question 5

What is interstitial hydrostatic pressure?

Answer 5

Pressure exerted by interstitial fluid pushing blood in the capillaries

Question 6

What is blood colloid osmotic pressure?

Answer 6

plasma pressure that draws blood into capillary

Question 7

What is interstitial colloid osmotic pressure?

Answer 7

osmotic pressure that pulls fluid out of the capillary

Question 8

How can you measure NET FILTRATION PRESSURE?

Answer 8

Net hydrostatic pressure - Net osmotic pressure

Question 9

How can net HYDROSTATIC pressure be calculated?

Answer 9

Capillary hydrostatic pressure - interstitial fluid hydrosstatic pressure

Question 10

What movement of the fluid does net HYDROSTATIC pressure favour?

Answer 10

Movement of the fluid out of the capillary into interstitial fluid= FILTRAATION is favoured

Question 11

What movement of the fluid does the net OSMOTIC pressure favour?

Answer 11

Favours reabsorption of fluid into capillary

Question 12

Where will fluid move with positive NET filtration pressure?

Answer 12

into interstitial fluid

Question 13

Where will fluid move when -ve NET filtration pressure?

Answer 13

reabsorption into capillary

Question 14

What happens to Capillary hydrostatic pressure (CHP) from arteriole to venous end?

Answer 14

It decreases from 35 to 18

Question 15

What is the mmHg pressure value of Cpillary hydrostatic pressure?

Answer 15

35

Question 16

What is interstitial hydrostaTIC PRESsure mmHg value?

Answer 16

0

Question 17

What is the typical BLOOD colloid osmotic pressure?

Answer 17

25 (across all capillary)

Question 18

What is the typical mmHg interstitial colloid osmotic pressure?

Answer 18

0

Question 19

WHAT is net Hydrosattic pressure value in mmHg?

Answer 19

35 to 18 to venule end

Question 20

What is net colloid osmotic pressure value in mmHg?

Answer 20

25 across all capillary (25 - 0)

Question 21

Why is FILTRATION greater than reabsorption overall?

Answer 21

Because net HYDROSTRATIC pressure is 35 compared to net OSMOTIC pressure which is 25, so more fluid exit the capillaries than it is reabsorbed to overall during the day

Question 22

What is the typical net filtration pressure?

Answer 22

NFP = NHP - NCOP = 10

Question 23

How does hypertension affect the net filtration pressure at arteriole end?

Answer 23

• Increased net filtration pressure to 20 (45 - 25 instead of 35 - 25)
• High BP = Higher CHP which means more filtration
• which collects in extremities
• leads to systemic oedema

Question 24

How would haemorrhage affect net filtration pressure at venous end?

Answer 24

• Haemorrhage = lower BP = Lower CHP = 5 instead of 18

instead 18 - 25, its 5-25 = -20 net filtration pressure, so more fluid is reabsorbed into blood
- leads to increase in BP and CO

Question 25

What happens if BCOP increases to 30 at venous end?

Answer 25

18-30 = -12 NFP
more fluid from tissues to blood
leads to dehydration

Question 26

What happens if ICOP increases to 10 at venous end?

Answer 26

25- 10 = 15 net osmotic pressure
net filtration pressure is = NHP- NOP= at venous end NHP = 18
18 - 15 = +3
Local swelling (oedema)