Chapter 12

Question 1

where is temperature controlled?

Answer 1

thermoregulatory centre

Question 2

where is the thermoregulatory centre?

Answer 2

the hypothalamus, brain

Question 3

how does the thermoregulatory centre detect changes?

Answer 3

receptors test temperature of blood in brain

receptors in skin

Question 4

how dos the body cool down

Answer 4

sweat

vasodilation

Question 5

what is vasodilation?

Answer 5

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

Question 6

how does sweat cool you down?

Answer 6

it evaporates from the skin taking heat with it

Question 7

how does the body warm up

Answer 7

vasoconstriction
shiver
hairs stand on end

Question 8

how does hair standing on end warm you up?

Answer 8

it catches and traps an insulating layer of air

Question 9

how does shivering warm you up?

Answer 9

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

Question 10

what is vasoconstriction and how does it warm you up?

Answer 10

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

Question 11

why should the body not get too hot?

Answer 11

denatures enzymes

Question 12

what are the two main waste products?

Answer 12

carbon dioxide and urea

Question 13

when is carbon dioxide produced?

Answer 13

respiration

Question 14

why is carbon dioxide so dangerous?

Answer 14

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

Question 15

how do you get rid of CO2

Answer 15

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

Question 16

how is urea produced?

Answer 16

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

Question 17

where is urea produced?

Answer 17

liver

Question 18

why is urea dangerous?

Answer 18

it is poisonous to cells

Question 19

how do you get rid of urea?

Answer 19

kidneys filter it out

Question 20

3 ways in which you lose water from body

Answer 20

exhaling
sweat
urine

Question 21

function of kidneys

Answer 21

filters substances like urea from the blood

maintains a healthy water level

Question 22

how do the kidneys conserve water?

Answer 22

you produce very concentrated urine with not much water

Question 23

how do kidneys work?

Answer 23

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

Question 24

what is selective reabsorption?

Answer 24

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

Question 25

what does ADH stand for?

Answer 25

anti diuretic hormone

Question 26

where does ADH come from?

Answer 26

pituitary gland in brain

Question 27

how does ADH affect water concentration in blood?

Answer 27

it tells the kidneys how much water to conserve

Question 28

if the water conc. is too high what happens

Answer 28

less ADH so less water reabsorbed

Question 29

if water conc. is too low what happens

Answer 29

more ADH so more water reabsorbed

Question 30

two options of treating kidney failure

Answer 30

dialysis | transplant

Question 31

how does a dialysis machine work?

Answer 31

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

Question 32

importance of a partially permeable membrane in dialysis

Answer 32

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

Question 33

importance of dialysis fluid having same concentration of minerals as blood

Answer 33

so the minerals don't cross into the fluid by diffusion

Question 34

why should the dialysis fluid contain no urea?

Answer 34

steep concentration gradient - effective diffusion of urea

Question 35

why is kidney failure life threatening

Answer 35

build up of urea

Question 36

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

Answer 36

their kidneys can't filter substances like salt and protein out

Question 37

what process does dialysis depend on?

Answer 37

diffusion

Question 38

why is it important that dialysis fluid is circulated?

Answer 38

urea will build up in one place so doesn't diffuse out of blood as same concentration

Question 39

what is the main problem with kidney transplants?

Answer 39

rejection

Question 40

why are donated kidneys often rejected?

Answer 40

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

Question 41

what drugs are used to stop rejection?

Answer 41

immunosuppressants

Question 42

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

Answer 42

kidney hasn't begun to shut down - higher chance of success | family members = closer tissue types

Question 43

advantages of kidney transplants (3)

Answer 43

no dialysis can live normal life cheaper long term

Question 44

disadvantages of kidney transplants (4)

Answer 44

rejection immunosuppressants only last for 9 years waiting list

Question 45

advantages of dialysis (4)

Answer 45

immediate treatment no surgery no threat of rejection no immunosuppressants

Question 46

disadvantages of dialysis (4)

Answer 46

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

Question 47

how and where is water made

Answer 47

respiration | all body cells

Question 48

how and where is CO2 made

Answer 48

respiration | all body cells

Question 49

why do you urinate more in winter?

Answer 49

in summer you can sweat out excess water

Question 50

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

Answer 50

pale | less concentrated - more water to dilute it

Question 51

side effect of dialysis

Answer 51

no way of fighting other infections

Question 52

where are the two types of temperature sensors found?

Answer 52

skin and brain

Question 53

what vessel enters kidney?

Answer 53

renal artery

Question 54

what vessel leaves kidney?

Answer 54

renal vein

Question 55

3 ways in which you can gain water

Answer 55

respiration eating drinking

Question 56

4 ways in which water can leave body

Answer 56

faeces breathing sweating urinating

Question 57

how does a healthy kidney produce urine?

Answer 57

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