TRANSPORT IN MAMMALS Flashcards Preview

3 ADAPTIONS FOR TRANSPORT IN ANIMALS > TRANSPORT IN MAMMALS > Flashcards

Flashcards in TRANSPORT IN MAMMALS Deck (15):
1

pulmonary circulation (2)

- right side of the heart pumps deoxygenated blood to lungs
- left side of the heart pumps oxygenated blood to heart

2

systemic circulation (2)

- left side of the heart pumps oxygenated blood to tissues
- right side of the heart pumps deoxygenated back to heart

3

how many times does blood pass through the heart in a double circulatory system?

- twice, once through the right and once through the left

4

three types of blood vessels (3)

- arteries, away from heart
- veins, to heart
- capillaries - between veins and arteries

5

layers of blood vessel (3)

- endothelium - innermost layer
- tunica media
- tunica externa - outermost layer

6

endothelium (4)

- inner layer
- one-cell thick
- smooth lining to reduce friction
- minimum resistance to blood flow

7

tunica media (4)

- middle layer
- elastic fibres and smooth muscle
- allow stretching for changes in pressure
- after stretching to certain degree fibres recoil pushing blood through (felt as pulse) maintains blood pressure

8

tunica externa (2)

- outer layer
- contains collagen fibres to resist overstretching

9

Arteries (3)

- carry blood from heart
- thick muscular wall to withstand high pressure blood
- branch into arterioles, then capilaries

10

Capilaries (2)

- penetrate all tissues and organs of the body
- blood from capillaries collect into venules which take blood to veins and return them to the heart

11

Veins

- large lumen and thinner walls
- lower pressure

12

How does blood in veins above the heart return to the heart?

- via gravity

13

How does blood in veins below the heart return to the heart? (2)

- peristalsis, alternating pressure from surrounding muscles
- valves prevent backflow

14

What problems can faulty valves cause? (2)

- varicose veins
- heart failure

15

describe capillary walls

- 1-cell thick walls (only endothelium on a basement membrane)
- permeable to water and solutes (for exchange between tissues and blood)
- small diameter, slows rate of blood flow (so plenty of time to exchange tissues)