Chapter 8: transport in mammals Flashcards

1
Q

Describe the mammalian circulatory system

A
  • closed double circulation

- consisting of a heart, blood vessels and blood

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2
Q

what are arteries?

A

vessels carrying blood away from the heart

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3
Q

what are veins?

A

vessels carrying blood to the heart

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4
Q

what are arteries made of?

A
  • inner endotelium called the tunica intima
  • tunica media
  • tunica externa
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5
Q

what is the tunica media?

A

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

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6
Q

what is the tunica externa

A

outer coating of arteries containing elastic fibres and collagen fibres

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7
Q

what is the tunica intima?

A

inner layer made of squamous epilthelium cells

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8
Q

what are the distinctive characteristics of the arteries?

A

strength and elasticity

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9
Q

why do artery walls need to be extremely strong?

A

-to withstand the blood pressure leaving the heart

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10
Q

why do artery walls need to be elasticy

A

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

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11
Q

what are arterioles?

A

smaller vessels than the arteries

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12
Q

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

A

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

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13
Q

what are capillaries?

A

the smallest of all blood vessels

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14
Q

what is the function of capillaries?

A

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

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15
Q

what are capillary beds?

A

networks of capillaries

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16
Q

what are semi-lunar valves?

A

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

17
Q

how is blood in the veins moved?

A

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

18
Q

give another name for red blood cells

A

erythrocytes

19
Q

what causes the red colour in red blood cells?

A

haemoglobin

20
Q

what is the main function of haemoglobin?

A

to transport oxygen from lungs to respiring tissues

21
Q

give 4 adaptations of red blood cells

A
  • bioncave disc shape
  • very small diameter
  • very flexible (can deform so they can pass through vessels)
  • have no nucleus, mitochondria or endoplasmic reticulum
22
Q

what are lymphatics?

A

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

23
Q

describe the role of the valves in the lymph vessel walls

A
  • wide enough to allow large protein molecules to pass through
  • important because they are too big for capillaries
24
Q

what are lymph nodes?

A
  • 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
Q

describe the structure of a white blood cell

A
  • nucleus
  • larger than red blood cells
  • spherical or irregular in shape
26
Q

what is the purpose of a phagocyte?

A

cells that destroy invading microorganisms by phagocytosis

27
Q

give another example of a phagocyte

A

monocytes

28
Q

how do lymphocytes destroy microorganisms?

A

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

29
Q

describe the structure of haemoglobin

A
  • 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
Q

what does saturated mean?

A

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

31
Q

describe the saturation of oxygen in an actively respiring muscle?

A

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
Q

give the first reaction with carbonic anhydrase

A

C02 + H20 ==> H2CO3

33
Q

give the first reaction in the cytoplasm of red blood cells

A

H2C03 ==> H+ + HCO3-