Excretion in Humans

Question 1

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

Answer 1

waste products

Question 2

excretion is

Answer 2

the removal of metabolic waste products from the body

Question 3

waste product found in the lungs

Answer 3

carbon dioxide

Question 4

main roles of the kidney (2)

Answer 4

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

Question 5

waste product found in the skin

Answer 5

sweat

Question 6

excretory products of the kidney

Answer 6

urea, ions and water

Question 7

how do the kidneys carry out their main functions

Answer 7

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

Question 8

what is the end product

Answer 8

urine

Question 9

process of ultrafiltration

Answer 9

• 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.

Question 10

what is the filtered liquid called after ultrafiltration

Answer 10

glomerular filtrate

Question 11

process of selective reabsorption

Answer 11

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

Question 12

why is it called selective reabsorption

Answer 12

because only a selective few substances are reabsorbed

Question 13

water reabsorption process

Answer 13

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

Question 14

why is water reabsorption important/ needed

Answer 14

because the water is needed for osmoregulation

Question 15

once out of the nephron where does urine go

Answer 15

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

Question 16

what is urea

Answer 16

a toxic waste product

Question 17

where is urea produced

Answer 17

liver

Question 18

what is urea made from

Answer 18

excess amino acids

Question 19

what is osmoregulation

Answer 19

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

Question 20

why is osmoregulation important

Answer 20

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

Question 21

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

Answer 21

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

Question 22

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

Answer 22

they do not function properly

Question 23

what can too much water in the cells lead to

Answer 23

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

Question 24

what can too little water in the cells lead to

Answer 24

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

Question 25

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

Answer 25

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

Question 26

what body part produces urea

Answer 26

liver

Question 27

crenation

Answer 27

dehydrated cells

Question 28

lysis

Answer 28

bursting of cells / excess water in cells

Question 29

bowmans capsule does what

Answer 29

surrounds glomerulus

Question 30

glomerulus is a

Answer 30

bundle of capillaries where ultrafiltration occurs

Question 31

proximal convoluted tubule

Answer 31

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

Question 32

collecting duct

Answer 32

end part of nephron where urine collects

Question 33

loop of henle

Answer 33

vital component for maintenance of water balance

Question 34

why is excretion so important

Answer 34

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

Question 35

what effect could waste have on cells (2)

Answer 35

- toxic - denature their enzymes - osmotic

Question 36

what is the osmotic effect that waste could have in cells

Answer 36

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

Question 37

excretory organs of the human body

Answer 37

skin kidneys lungs liver

Question 38

where do metabolic reactions take place

Answer 38

in every cell of a living organism

Question 39

what are the 2 sources of water in the body

Answer 39

- water produced as a result of aerobic respiration - water in the diet

Question 40

2 ways water is lost

Answer 40

Via the lungs during exhalation (breathing out) Lost from the skin as sweat (along side mineral ions and urea)

Question 41

2 key functions of the urinary system

Answer 41

- filter and remove waste products - control water levels

Question 42

the aorta branches to form what artery

Answer 42

renal artery

Question 43

what does the renal artery deliver

Answer 43

oxygenated blood to the kidneys

Question 43

de-oxygenated blood will exit the kidneys through the

Answer 43

renal vein

Question 44

three regions of the kidney

Answer 44

- cortex (outermost layer) - medulla (inner section) - renal pelvis

Question 45

what is the renal pelvis

Answer 45

tube that links kidney to ureter

Question 46

will blood in the renal vein contain waste products and why

Answer 46

NO because they will have been filtered out by the kidney

Question 47

what parts of the kidney would be found in the cortex

Answer 47

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

Question 48

what part of the kidney holds the loop of henle

Answer 48

medulla

Question 49

how is blood pressure increased in the glomerulus

Answer 49

narrowing of cappilaries

Question 50

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

Answer 50

high

Question 51

glucose is reabsorbed by

Answer 51

active transport

Question 52

cells in the proximal convoluted tubule contain many

Answer 52

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

Question 53

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

Answer 53

diffusion and active transport loop of henle

Question 54

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

Answer 54

water osmosis

Question 55

what is ADH

Answer 55

anti-diuretic hormone

Question 56

what does ADH make the collecting duct become

Answer 56

more permeable so more water is reabsorbed back into the fluid

Question 57

what does the brain tell the _____to release according to __

Answer 57

- pituitary gland - ADH - according to how much is needed in the blood

Question 58

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

Answer 58

hypothalamus pituitary gland

Question 59

what produces ADH

Answer 59

pituitary gland

Question 60

if water content is too high ...

Answer 60

- 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

Question 61

if water content is too low

Answer 61

- 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

Question 62

How much ADH is released depends on

Answer 62

how much water the kidneys need to reabsorb from the filtrate

Question 63

urine contains a mixture of

Answer 63

urea excess mineral ions excess water

Question 64

large quantities of urine are usually what colour and why

Answer 64

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

Question 65

small quantities of urine are usually what colour and why

Answer 65

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

Question 66

why will concentration of urine change (3)

Answer 66

water intake temperature exercise

Question 67

how does water intake affect the concentration of urine

Answer 67

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

Question 68

how does temperature affect the concentration of urine

Answer 68

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

Question 69

how does exercise affect the concentration of urine

Answer 69

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

Question 70

what does the bladder do

Answer 70

collects urine, holds it