Cardiovascular system 4

Question 1

What is the function of capillaries

Answer 1

Exchange site between blood and tissue

Question 2

Describe the physical properties of capillaries

Answer 2

Thin walls - to allow easier passive diffusion
Large cross sectional area of capillary bed - helps same volume of blood move with lower P
Slow and smooth blood flow - (achieved though systole)

Question 3

What junctions are in the capillary walls

Answer 3

Tight junction

Question 4

What are capillary sphincters

Answer 4

Made of smooth muscle and control the movement of blood through the capillary bed

Question 5

What is shunting and when is it done

Answer 5

Sending blood directly into lymph rather than through capillary bed.
Used during thermoregulation so the heat of warm blood isn’t lost by being close to surface of skin

Question 6

What are the two sides of the capillary bed called

Answer 6

Terminal arteriole - last part of arteries

Post capillary venule - first part after artery

Question 7

What are the three types of capillary structure

Answer 7

Continuous
Fenestrated
Sinusoidal

Question 8

Describe Continuous structure of capillaries

Answer 8

Continuous cellular boundary and basement membrane.

Molecules need to pass through both membranes to get into/out of the cell

Question 9

How do things diffuse across membrane with continuous structure

Answer 9

Vesicles move molecules across the epithelium membrane

Question 10

Describe Fenestrated structure of capillaries

Answer 10

Has fenestrations in membrane to make leakier - due to areas where molecules don’t need to cross boundary
Basement membrane

Question 11

Describe Sinusoidal structure of capillaries

Answer 11

Lager diameter - allows more red blood cells down at once
Intercellular gaps in capillary wall (not big enough for blood cell to escape)
Holes in basement membrane

Question 12

What is the lymph vascular system

Answer 12

Open-entry drainage system drains leakages back to blood, screening though lymph nodes for foreign antigens

Question 13

What does the lymph system drain

Answer 13

Tissue fluid
Plasma proteins from tissues
Absorbs fat from intestine and transports back to blood

Question 14

What are lacteals

Answer 14

Special group of lymphatic vessels that drain fat laden lymph from small intestine into collecting vessel

Question 15

What is the collecting vessel that lacteals drain into

Answer 15

Cisterna chyli - holding chamber - under gastrointestinal mucosa

Question 16

Why does the lymphatic vessels have valves

Answer 16

They have thing walls and use valves to prevent back flow of fluid

Question 17

How do the lymphatic vessels take up fluid

Answer 17

The cells that make up the wall have rough loose connections - flap like openings

Question 18

What is the basic lymph node structure

Answer 18

Has multiple afferent lymphatics bringing in lymph and one efferent moving lymph out
Meshwork of fibres with immune cells hanging off

Question 19

What is the danger of cancer getting into the lymph nodes

Answer 19

If a part of a cance breaks off and gets into the lymph nodes it can then be taken to the blood and be distributed through the whole body, metastasising