lecture 7

Question 1

what 3 things does the capillary function demand

Answer 1

very thin walls for efficient diffusion
Large total cross sectional area of capillary bed.
slow and smooth blood flow

Question 2

what allows the slow blood flow in capillaries

Answer 2

despite the quick and somewhat pulsatile flow of the ateries, the CSA of the capillary beds is large which slows the pulsatile nature.

Question 3

describe the makeup of the capillary

Answer 3

it is a single endothelia cell which is rounded to join to itself via tight junctions. thus the capillary has a thin wall diameter of 1 cell

Question 4

3 types of capillary

Answer 4

continuous, fenestrated and sinusoidal

Question 5

describe the continuous capillary

Answer 5

8-10 micron in diameter, continuous basement membrane and no holes in the membrane

Question 6

describe the fenestrated capillary

Answer 6

8-10 micron in diameter, continuous basement membrane, does have fenestrations in the membrane, these fenestrations allowing movement of water soluble molecules

Question 7

describe the sinusoidal capillary

Answer 7

30-40 um diameter, the larger capillary type. have discontinuous basement membrane and discontinuous epithelial lining. these are not just for gas exchange, which explains large diffusion distance.

Question 8

function of sinusoidal capillary

Answer 8

to allow plasma to pass into the surrounding tissues without the RBCs.

Question 9

where can we find each of the capillary types

Answer 9

continuous- most common type- skeletal and cardiac muscle
fenestrated- kidney and the small intestine
sinusoidal- the liver sinusoids

Question 10

what happens in the liver sinusoids

Answer 10

where blood is cleaned and detoxified.

Question 11

what are the 4 types of movement facilitated by the capillaries

Answer 11

water soluble movement through intercellular clefts
lipid soluble diffusion through the plasma membrane
active transport via vesicles- movement of large substances
water soluble movement through fenestrations and sinusoids.

Question 12

what movement types do the continuous capillaries allow

Answer 12

intercellular clefts, diffusion across membrane and active vesicle transport

Question 13

what movement types do the sinusoidal and fenestrated capillaries allow

Answer 13

intercellular clefts, diffusion across membrane and active vesicle transport and movement through fenestrations

Question 14

functions of the lymph vascular system

Answer 14

1. Drains excess tissue fluid & plasma proteins from
   tissues and returns them the blood.
2. Filters foreign material from the lymph.
3. ‘Screens
   ’ lymph for foreign antigens & responds by
   releasing antibodies & activated immune cells.
4. Absorbs fat from intestine and transports to blood.

Question 15

describe the structure of the lymphatics in the periphery

Answer 15

Commence as large, blind ending capillaries. with a wall that is one cell thick, they contain valves but do NOT CONTAIN RBC

Question 16

what does blind ending capillaries mean

Answer 16

this means there is no specific, constant inflow into the capillary.

Question 17

what collects lymph from the small intestine

Answer 17

the lacteals

Question 18

where do the lacteals drain fat laden lymph to and where does this lead to

Answer 18

to the cisterna chyli which then leads to the venous system to be recycled

Question 19

whats the path of lymph from the right breast

Answer 19

the auxillary lymph nodes, to the right thoracic duct to the right subclavian vein

Question 20

whats the path for the left breast lymph

Answer 20

the auxillary nodes to the thoracic duct then to the left subclavian vein

Question 21

why is breast cancer so dangerous

Answer 21

because there are many lymph vessels in the breast, so the cancerous tissue can easily get into lymph and blood system. thus travelling round the body.