Chapter 8: transport in mammals Flashcards Preview

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Flashcards in Chapter 8: transport in mammals Deck (33):
1

Describe the mammalian circulatory system

-closed double circulation
-consisting of a heart, blood vessels and blood

2

what are arteries?

vessels carrying blood away from the heart

3

what are veins?

vessels carrying blood to the heart

4

what are arteries made of?

-inner endotelium called the tunica intima
-tunica media
-tunica externa

5

what is the tunica media?

middle layer of arteries which contains smooth muscle, collagen and elastic fibres

6

what is the tunica externa

outer coating of arteries containing elastic fibres and collagen fibres

7

what is the tunica intima?

inner layer made of squamous epilthelium cells

8

what are the distinctive characteristics of the arteries?

strength and elasticity

9

why do artery walls need to be extremely strong?

-to withstand the blood pressure leaving the heart

10

why do artery walls need to be elasticy

to reduce the likelihood that they will burst because of the high blood pressure

11

what are arterioles?

smaller vessels than the arteries

12

what is the main difference between the arteries and the arterioles?

the arterioles have a greater proportion of smooth muscle so that the muscle can contract and reduce/ increase blood flow

13

what are capillaries?

the smallest of all blood vessels

14

what is the function of capillaries?

to take blood as close as possible to all cells, allowing rapid transfer of substances between cells and blood

15

what are capillary beds?

networks of capillaries

16

what are semi-lunar valves?

half-moon valves that allow blood to move towards the heart, but not away from it

17

how is blood in the veins moved?

-muscles contract and the blood in the veins is pushed up through the valves

18

give another name for red blood cells

erythrocytes

19

what causes the red colour in red blood cells?

haemoglobin

20

what is the main function of haemoglobin?

to transport oxygen from lungs to respiring tissues

21

give 4 adaptations of red blood cells

-bioncave disc shape
-very small diameter
-very flexible (can deform so they can pass through vessels)
-have no nucleus, mitochondria or endoplasmic reticulum

22

what are lymphatics?

tiny, blind-ending vessels that are found in almost all body tissue

23

describe the role of the valves in the lymph vessel walls

-wide enough to allow large protein molecules to pass through
-important because they are too big for capillaries

24

what are lymph nodes?

-involved in the protection against disease
-bacteria is removed by white blood cells as the lymph passes through a node
-some white blood cells in the nodes secrete antibodies

25

describe the structure of a white blood cell

-nucleus
-larger than red blood cells
-spherical or irregular in shape

26

what is the purpose of a phagocyte?

cells that destroy invading microorganisms by phagocytosis

27

give another example of a phagocyte

monocytes

28

how do lymphocytes destroy microorganisms?

-secrete chemicals called antibodies, which attatch to and destroy the invading cells

29

describe the structure of haemoglobin

-four polypeptides
-each polypeptide contains one haem group
-each haem group can combine with one oxygen molecule
-one haemoglobin can carry 8 oxygen molecules

30

what does saturated mean?

a sample of haemoglobin that has combined with the maximum amount of oxygen

31

describe the saturation of oxygen in an actively respiring muscle?

the partial pressure will be about 20-25% saturated
the haemoglobin from the lungs carries lots of oxygen and releases around 75% at the muscles

32

give the first reaction with carbonic anhydrase

C02 + H20 ==> H2CO3

33

give the first reaction in the cytoplasm of red blood cells

H2C03 ==> H+ + HCO3-