Exchange and the lymphatic system Flashcards
1
Q
Capillary properties
A
- Numerous
- Thin-walled: small diffusion barrier
- Small diameter: large surface area:volume ratio
2
Q
Types of capillaries (3)
A
- Continuous
- Fenestrated
- Discontinuous
3
Q
Continuous capillaries
A
No clefts or pores e.g. brain
Clefts only e.g. muscles
4
Q
Fenestrated capillaries
A
Cleft and pores e.g. intestines
5
Q
Discontinuous capillaries
A
Clefts and massive pores e.g. liver
6
Q
Methods of exchange (2)
A
- Diffusion: self-regulating, non-saturable and non-polar substances through clefts/channels
- Carrier-mediated transport e.g. glucose
7
Q
Blood-brain barrier function
A
- Highly selective impermeable border of endothelial cells to protect against circulating toxins/pathogens that could cause infection, while allowing passage of vital nutrients
8
Q
Blood-brain barrier structure
A
Continuous capillaries with no clefts or pores and glucose-specific protein carriers
9
Q
Normal clotting process
A
Formation of platelet plug and fibrin clot
10
Q
Clotting prevention techniques in capillaries (5)
A
- Stops blood contacting collagen
- Prostacyclin and NO production
- TFPI production
- Thrombomodulin and heparin expression
- t-Pa secretion
11
Q
- Stops blood-collagen contact
A
Prevents platelet aggregation
12
Q
- Prostacyclin and nitric oxide production
A
Inhibit platelet aggregation
13
Q
- Tissue factor and pathway inhibitor production
A
Stops thrombin production
14
Q
- Thrombomodulin and heparin expression
A
Inactivates thrombin
15
Q
- Tissue plasminogen activator secretion
A
Plasminogen -> plasmin and digest clot
