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BIOLOGY test rev > Excretion in Humans > Flashcards

Excretion in Humans Flashcards

Topic 2 i. 2

1
Q

many of the necessary metabolic reactions that take place in the cells of organisms produce

A

waste products

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2
Q

excretion is

A

the removal of metabolic waste products from the body

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3
Q

waste product found in the lungs

A

carbon dioxide

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4
Q

main roles of the kidney (2)

A
  • removal of urea from blood
  • adjustment of ion (salt) levels in the blood
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5
Q

waste product found in the skin

A

sweat

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6
Q

excretory products of the kidney

A

urea, ions and water

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7
Q

how do the kidneys carry out their main functions

A

by filtering stuff out of the blood under high pressure, and then reabsorbing the useful things.

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8
Q

what is the end product

A

urine

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9
Q

process of ultrafiltration

A
  • blood from the renal artery flows through the glomerulus
  • a high blood pressure squeezes water, urea and ions and glucose out of the blood and into the bowmans capsule
  • the membranes between the bowmans capsule and the blood vessels act like filters so big molecules (proteins) and blood cells aren’t squeezed out and stay in the blood.
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10
Q

what is the filtered liquid called after ultrafiltration

A

glomerular filtrate

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11
Q

process of selective reabsorption

A

after the glomerular filtrate enters the bowmans capsule, glucose is the first substance to be reabsorbed at the proximal convoluted tube.

  • all the glucose is reabsorbed from the proximal convoluted tubule so that it can be used in respiration. This happens through active transport
  • sufficient ions are reabsorbed, not the excess ones
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12
Q

why is it called selective reabsorption

A

because only a selective few substances are reabsorbed

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13
Q

water reabsorption process

A

water is reabsorbed from the collecting duct in different amounts depending on how much water the body needs at a time

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14
Q

why is water reabsorption important/ needed

A

because the water is needed for osmoregulation

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15
Q

once out of the nephron where does urine go

A

nephron
through ureter
down to the bladder where it is stored
released by urethra

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16
Q

what is urea

A

a toxic waste product

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17
Q

where is urea produced

A

liver

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18
Q

what is urea made from

A

excess amino acids

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19
Q

what is osmoregulation

A

the process of maintaining water and salt concentrations across membranes within the body

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20
Q

why is osmoregulation important

A

maintaining water levels in the body is vital to prevent harmful changes occurring to cells of the body as a result of osmosis

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21
Q

what is one way that the body can balance the water coming in against the water going out?

A

by adjusting the amount of water that is excreted by the kidneys in the urine,
if a person is sweating a lot or hans’t drunk enough water, the kidneys can reabsorb more water so that less is lost in the urine and water balance is maintained

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22
Q

if body cells lose or gain too much water by osmosis what happens to them?

A

they do not function properly

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23
Q

what can too much water in the cells lead to

A

cells swelling as water moves into them, this has a diluting effect and can lead to cell lysis (bursting)

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24
Q

what can too little water in the cells lead to

A

cells lose water by osmosis as there is a too high concentration of ions and this has a dehydrating effect and can lead to cell death

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25
Q

where can water being lost be controlled and where can it not be controlled

A

cannot be controlled in the lungs or skin
can be controlled in the production of urine by the kidneys

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26
Q

what body part produces urea

A

liver

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27
Q

crenation

A

dehydrated cells

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28
Q

lysis

A

bursting of cells / excess water in cells

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29
Q

bowmans capsule does what

A

surrounds glomerulus

30
Q

glomerulus is a

A

bundle of capillaries where ultrafiltration occurs

31
Q

proximal convoluted tubule

A

selectively reabsorbs essential nutrients, ions, and a large amount of water back into the bloodstream.

32
Q

collecting duct

A

end part of nephron where urine collects

33
Q

loop of henle

A

vital component for maintenance of water balance

34
Q

why is excretion so important

A

because a build up of waste products can be harmful to cells

35
Q

what effect could waste have on cells (2)

A
  • toxic - denature their enzymes
  • osmotic
36
Q

what is the osmotic effect that waste could have in cells

A

when in high concentrations, tissue fluid can become more concentrted, drawing water out of cells which can prevent the cells from functioning properly
it uses up storage place within cells which should be saved for useful molecules not waste products

37
Q

excretory organs of the human body

A

skin
kidneys
lungs
liver

38
Q

where do metabolic reactions take place

A

in every cell of a living organism

39
Q

what are the 2 sources of water in the body

A
  • water produced as a result of aerobic respiration
  • water in the diet
40
Q

2 ways water is lost

A

Via the lungs during exhalation (breathing out)

Lost from the skin as sweat (along side mineral ions and urea)

41
Q

2 key functions of the urinary system

A
  • filter and remove waste products
  • control water levels
42
Q

the aorta branches to form what artery

A

renal artery

43
Q

what does the renal artery deliver

A

oxygenated blood to the kidneys

43
Q

de-oxygenated blood will exit the kidneys through the

A

renal vein

44
Q

three regions of the kidney

A
  • cortex (outermost layer)
  • medulla (inner section)
  • renal pelvis
45
Q

what is the renal pelvis

A

tube that links kidney to ureter

46
Q

will blood in the renal vein contain waste products and why

A

NO because they will have been filtered out by the kidney

47
Q

what parts of the kidney would be found in the cortex

A

glomerulus & bowmans capsule
proximal convoluted tubule
distal convoluted tubule
collecting duct

48
Q

what part of the kidney holds the loop of henle

A

medulla

49
Q

how is blood pressure increased in the glomerulus

A

narrowing of cappilaries

50
Q

for ultrafiltration to happen, should the blood pressure be high or low

A

high

51
Q

glucose is reabsorbed by

A

active transport

52
Q

cells in the proximal convoluted tubule contain many

A

mitochondria as glucose is absorbed by active transport and thats an active process

53
Q

necessary salts are absorbed back into the blood by ___ and ____ in the ___ __ ___

A

diffusion and active transport
loop of henle

54
Q

as salts are absorbed back into the blood, ___ follows by ___

A

water
osmosis

55
Q

what is ADH

A

anti-diuretic hormone

56
Q

what does ADH make the collecting duct become

A

more permeable so more water is reabsorbed back into the fluid

57
Q

what does the brain tell the _____to release according to __

A
  • pituitary gland
  • ADH
  • according to how much is needed in the blood
58
Q

any change in water levels in the blood are detected by the ______ which then sends a signal to the ____

A

hypothalamus
pituitary gland

59
Q

what produces ADH

A

pituitary gland

60
Q

if water content is too high …

A
  • The pituitary gland releases less ADH which leads to less water being reabsorbed in the collecting ducts of the kidney by osmosis (the collecting ducts become less permeable to water)
  • As a result, the kidneys produce a large volume of dilute urine
61
Q

if water content is too low

A
  • The pituitary gland releases more ADH which leads to more water being reabsorbed in the collecting ducts of the kidney by osmosis (the collecting ducts become more permeable to water)
  • As a result, the kidneys produce a small volume of concentrated urine
62
Q

How much ADH is released depends on

A

how much water the kidneys need to reabsorb from the filtrate

63
Q

urine contains a mixture of

A

urea

excess mineral ions

excess water

64
Q

large quantities of urine are usually what colour and why

A

pale yellow
because it contains a lot of water and so the urea is less concentrated

65
Q

small quantities of urine are usually what colour and why

A

darker yellow

because it contains little water and so the urea is more concentrated

66
Q

why will concentration of urine change (3)

A

water intake

temperature

exercise

67
Q

how does water intake affect the concentration of urine

A

the more fluids drunk, the more water will be removed from the body and so a large quantity of pale yellow, dilute urine will be produced

68
Q

how does temperature affect the concentration of urine

A

the higher the temperature the more water is lost in sweat and so less will appear in the urine, meaning a smaller quantity of dark yellow, concentrated urine will be produced

69
Q

how does exercise affect the concentration of urine

A

the greater the level of exercise, the more water is lost in sweat and so less will appear in the urine, meaning a smaller quantity of dark yellow, concentrated urine will be produced

70
Q

what does the bladder do

A

collects urine, holds it

BIOLOGY test rev (56 decks)

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