Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology A level > 5.1.2 Excretion > Flashcards

5.1.2 Excretion Flashcards

excretion (56 cards)

Start Studying
1
Q

define excretion

A

excretion is the removal of the waste products of metabolism from the body. it helps to maintain metabolism and homeostasis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

and example of a metabolic product we remove from the body.

A

carbon dioxide from respiration. it is expelled from the lungs in mammals and gills in fish.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the function of the hepatic artery

A

supplies the liver with oxygenated blood from the heart so the liver has a good supply of oxygen for respiration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the function of the hepatic vein

A

takes deoxygenated blood away from the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the function of the hepatic portal vein

A

brings blood from the duodenum and ileum (small intestine) so it is rich in products from digestion so harmful products can be filtered out and broken down immediately

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what units is the liver made up from

A

liver lobules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is a sinusoid

A

where blood from the hepatic artery and hepatic portal vein mix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what do hepatocytes do

A

remove harmful substances from the blood and break them down into less harmful substances that then re-enter the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is a bile canaliculus

A

tubes which bile is secreted into from hepatocytes which connect up to the bile ducts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the function of a kupffer cell

A

removes bacteria and breaks down old red blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is in the centre of each lobule

A

central vein leading to hepatic vein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are excess amino acids broken down into

A

ammonia and keto acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the keto acids used for

A

enter the Krebs cycle and respired to give atp or stored as glycogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what cycle does ammonia enter

A

ornithine cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the purpose of the ornithine cycle

A

to convert ammonia to urea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the removal of amine groups from amino acids called

A

deamination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the first step in the ornithine cycle

A

ammonia is combined with carbon dioxide which reacts with ornithine to get citrulline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the second step of the ornithine cycle

A

ammonia is added to citrulline to make arginine. water is lost

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the third step of the ornithine cycle

A

water is added to arginine to regenerate ornithine and produce urea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how does the liver remove alcohol

A

breaks it down into ethanal and then acetic acid which is less harmful

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

name 2 substances that the liver breaks down

A

alcohol, paracetamol and insulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does excess alcohol do to the liver

A

cirrhosis of the liver (ells die leaving scar tissue blocking blood flow)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does the liver store

24
Q

what blood vessel does blood enter the kidney through

25
which is the darker thick layer of the kidney
medulla
26
what is the outer light layer of the kidney
cortex
27
what tube does urea leave kidney via
ureter
28
what is the pelvis of the kidney
area at the centre of the kidney where urine collects to be filtered into ureter
29
where does ultrafiltration take pace
glomerulus and bowman's capsule
30
what causes liquid and small molecules to filter out of capillaries.
the afferent capillary has a wider lumen then the efferent which causes there to be a high pressure pushing out the liquids and small molecules.
31
what is the basement membrane
stops larger molecules leaving the capillaries
32
what are podocytes
cells that are wrapped around the bowman's capsule and allow filtration
33
what is selective reabsorption
when useful substances are reabsorbed back into the blood
34
where does selective reabsorption take place
proximal convoluted tubule
35
how does selective reabsorption take place
1. sodium ions are co transported into cells of the PCT wall with glucose and amino acids 2. glucose and amino acids can enter blood via diffusion down a concentration gradient, sodium ions are actively transported into blood 3. water moves by osmosis to the blood from the PCT
36
what mechanism is used to reabsorb water in the loop of Henle
counter current multiplier
37
how is water reabsorbed in the loop of henle
1. sodium and chloride ions are actively transported out of the ascending limb which decreases the water potential in the medulla 2. water diffuses out the descending limb via osmosis 3some ions are reabsorbed into the descending limb to create a cycle
38
which limb of the loop of Henle is impermeable to water
ascending limb
39
what hormone controls water reabsorption
ADH (antidiuretic hormone)
40
what gland releases ADH
posterior pituitary gland
41
what detects changes in water potential
osmoreceptors in the hypothalamus
42
what happens when ADH binds to receptors on collecting duct membrane
1. stimulates CAMP production which stimulates vesicles containing aquaporins to bind with membrane 2 water can filter out of the aquaporin channels
43
is there more or less concentrated urine when more ADH is produced
more concentrated
44
how can we detect kidney failure
glomerular filtration rate is low
45
what can cause kidney failure
high blood pressure and infections
46
what problems does kidney failure cause
build up of waste, fluid accumulation, imbalance of electrolytes and anaemia
47
what is haemodialysis
patients blood is passed through a dialysis machine. waste filters out into dialysis fluid. anti clotting agents are added
48
advantages of haemodialysis
only need to do it a few times a week
49
what is peritoneal dialysis
dialysis fluid enters abdominal cavity and waste diffuses across peritoneum.
50
advantages of peritoneal dialysis
can be done at home
51
what is a kidney transplant
a new kidney is implanted to replace the damaged one
52
advantages of transplant
cheaper than continual dialysis and more convenient
53
disadvantages of transplant
can be rejected by immune system and risks of infection during surgery
54
how is urine used in pregnancy tests
1. monoclonal antibodies attached to a dye bind to hCG in urine of pregnant woman. 2. urine moves up to test strip where immobilised antibodies are fixed. hCG binds to them and dye is concentrated showing a positive result
55
what is the other method of chemical testing of urine
gas chromatography and mass spectrometry
56
what animals would have a longer loop of henle
ones living in dry environments because they will need to reabsorb more water

Biology A level (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions