Chapter 12 Flashcards

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1
Q

where is temperature controlled?

A

thermoregulatory centre

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2
Q

where is the thermoregulatory centre?

A

the hypothalamus, brain

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3
Q

how does the thermoregulatory centre detect changes?

A

receptors test temperature of blood in brain

receptors in skin

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4
Q

how dos the body cool down

A

sweat

vasodilation

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5
Q

what is vasodilation?

A

the blood vessels near the skin dilate so more blood is exposed to the cool air and cools down

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6
Q

how does sweat cool you down?

A

it evaporates from the skin taking heat with it

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7
Q

how does the body warm up

A

vasoconstriction
shiver
hairs stand on end

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8
Q

how does hair standing on end warm you up?

A

it catches and traps an insulating layer of air

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9
Q

how does shivering warm you up?

A

the movement of the skeletal system means more respiration (an exothermic process). this heats up body

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10
Q

what is vasoconstriction and how does it warm you up?

A

blood vessels constrict near the skin so less blood is available to the cold air

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11
Q

why should the body not get too hot?

A

denatures enzymes

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12
Q

what are the two main waste products?

A

carbon dioxide and urea

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13
Q

when is carbon dioxide produced?

A

respiration

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14
Q

why is carbon dioxide so dangerous?

A

when it dissolves, it produces acid which effects the enzymes in cells

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15
Q

how do you get rid of CO2

A

diffuses from cells into blood stream
diffuses from blood stream into lungs
this air is exhaled

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16
Q

how is urea produced?

A

breakdown of excess amino acids turns into ammonia, which turns into urea

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17
Q

where is urea produced?

A

liver

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18
Q

why is urea dangerous?

A

it is poisonous to cells

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19
Q

how do you get rid of urea?

A

kidneys filter it out

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20
Q

3 ways in which you lose water from body

A

exhaling
sweat
urine

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21
Q

function of kidneys

A

filters substances like urea from the blood

maintains a healthy water level

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22
Q

how do the kidneys conserve water?

A

you produce very concentrated urine with not much water

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23
Q

how do kidneys work?

A

filter blood
substances like urea are small enough to pass through membrane to be excreted
substances like glucose are too big
selectively absorbs molecules like water to be reabsorbed if you need them

24
Q

what is selective reabsorption?

A

the amount of water that is reabsorbed into your body depends on the circumstances (e.g. dehydrated)

25
Q

what does ADH stand for?

A

anti diuretic hormone

26
Q

where does ADH come from?

A

pituitary gland in brain

27
Q

how does ADH affect water concentration in blood?

A

it tells the kidneys how much water to conserve

28
Q

if the water conc. is too high what happens

A

less ADH so less water reabsorbed

29
Q

if water conc. is too low what happens

A

more ADH so more water reabsorbed

30
Q

two options of treating kidney failure

A

dialysis

transplant

31
Q

how does a dialysis machine work?

A

blood passes through dialysis fluid
toxins absorbed into fluid
fluid is cleaned and rid of toxins

32
Q

importance of a partially permeable membrane in dialysis

A

allows small particles like urea through but blocks useful, bigger ones like glucose

33
Q

importance of dialysis fluid having same concentration of minerals as blood

A

so the minerals donโ€™t cross into the fluid by diffusion

34
Q

why should the dialysis fluid contain no urea?

A

steep concentration gradient - effective diffusion of urea

35
Q

why is kidney failure life threatening

A

build up of urea

36
Q

why do people with kidney failure have to control what they eat?

A

their kidneys canโ€™t filter substances like salt and protein out

37
Q

what process does dialysis depend on?

A

diffusion

38
Q

why is it important that dialysis fluid is circulated?

A

urea will build up in one place so doesnโ€™t diffuse out of blood as same concentration

39
Q

what is the main problem with kidney transplants?

A

rejection

40
Q

why are donated kidneys often rejected?

A

the antigens on the surface of the new kidney will be different to those of the recipient so the immune system sees the kidney as a pathogen and attacks it

41
Q

what drugs are used to stop rejection?

A

immunosuppressants

42
Q

why are kidney transplants from living family members often better than transplants from unrelated, dead donors?

A

kidney hasnโ€™t begun to shut down - higher chance of success

family members = closer tissue types

43
Q

advantages of kidney transplants (3)

A

no dialysis
can live normal life
cheaper long term

44
Q

disadvantages of kidney transplants (4)

A

rejection
immunosuppressants
only last for 9 years
waiting list

45
Q

advantages of dialysis (4)

A

immediate treatment
no surgery
no threat of rejection
no immunosuppressants

46
Q

disadvantages of dialysis (4)

A

longterm more expensive
special diet
regular, time consuming sessions
can cause long term damage to body

47
Q

how and where is water made

A

respiration

all body cells

48
Q

how and where is CO2 made

A

respiration

all body cells

49
Q

why do you urinate more in winter?

A

in summer you can sweat out excess water

50
Q

what would urine look like in a cold day where you have drank a lot?

A

pale

less concentrated - more water to dilute it

51
Q

side effect of dialysis

A

no way of fighting other infections

52
Q

where are the two types of temperature sensors found?

A

skin and brain

53
Q

what vessel enters kidney?

A

renal artery

54
Q

what vessel leaves kidney?

A

renal vein

55
Q

3 ways in which you can gain water

A

respiration
eating
drinking

56
Q

4 ways in which water can leave body

A

faeces
breathing
sweating
urinating

57
Q

how does a healthy kidney produce urine?

A

blood passes into kidney
flows through PP membrane (blood cells are too big to cross)
all of glucose reabsorbed by active transport and diffusion
selective absorption of water and ions
releases urea in urine