Exchange and the lymphatic system

Question 1

what are the 3 different structures of capillaries?

Answer 1

continuous
fenestrated
discontinuous

Question 2

describe continuous capillaries.

Answer 2

may have no clefts or channels

may have no channels but clefts only

Question 3

where is a continuous capillary with no channels or clefts found?

Answer 3

brain

Question 4

where is a continuous capillary with clefts found?

Answer 4

muscle

Question 5

describe fenestrated capillaries.

Answer 5

contain clefts and channels

Question 6

where can a fenestrated capillary be found?

Answer 6

intestine

Question 7

describe a discontinuous capillary.

Answer 7

clefts and massive channels

Question 8

where can a discontinuous capillary be found?

Answer 8

liver

Question 9

what is the action of thrombin?

Answer 9

thrombin converts fibrinogen into fibrin

fibrin is involved in clot formation

Question 10

does prostacyclin increase or inhibit platelet aggregation?

Answer 10

prostacyclin inhibits platelet aggregation

Question 11

does NO inhibit or increase platelet aggregation?

Answer 11

inhibits platelet aggregations

Question 12

what are the different anti-clotting mechanisms of the endothelium?

Answer 12

stops blood contacting collagen
produces prostacyclin and NO
Produced tissue factor pathway inhibitor (TFPI)
expresses thrombomodulin
expresses heparin
secretes tissue plasminogen activator (t-PA)

Question 13

what is the role of tissue plasminogen activator?

Answer 13

activates plasminogen.

activated plasminogen is converted to plasmin which lyses and breaks down clots

Question 14

what is the role of tissue factor pathway inhibitor?

Answer 14

stops thrombin production

Question 15

what are the benefits of diffusion?

Answer 15

self regulation
non-saturable
non-polar substances can cross membrane
polar substances can travel through clefts and channels

Question 16

as you go along from arteries to venules, does the hydrostatic pressure increase or decrease?

Answer 16

decreases because pressure is higher in arteries thus higher hydrostatic pressure

Question 17

does the oncotic pressure increase or decrease as you move from arteriole to venules?
and why?

Answer 17

increases
as the water is lost due to increasing hydrostatic pressure, the proteins remain in the capillaries therefore increasing the concentration.
the increase in concentration builds up the oncotic pressure which draws more water into the capillaries.

Question 18

what is the volume of fluid lost and gained each day through the capillaries?

Answer 18

20l lost
17l regained
remaining 3l drained by lymphatic system

Question 19

what can increase capillary permeability?

Answer 19

inflammation e.g rheumatism