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biology > excretion > Flashcards

excretion Flashcards

1
Q

what are the main metabolic waste products in mammals

A

carbon dioxide - respiration

bile pigments - formed from breakdown of haemoglobin excreted in the bile to the s.intesine

nitrogenous waste products - breakdown of excess AA

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2
Q

what are the adaptations of the liver

A

rich blood supply

blood is supplied by two blood vessels
(hepatic artery + hepatic portal vein)

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3
Q

where does the hepatic portal vein carry blood from

A

contains products of digestion from intestines

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4
Q

what is the structure of a hepatocyte

A

large nucleus

prominent golgi body

lots of mitochondria

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5
Q

where is blood from the hepatic artery and hepatic portal vein mixed

what does this do

A

sinusoids

increases oxygen content

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6
Q

what do sinusoids contain

what is their function

A

kupffer cells

act as resident macrophages, ingesting foreign particles

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7
Q

where do hepatocytes secrete bile into

A

spaces called canaliculi

from there, biles drains into bile ductules carrying it to the gall bladder

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8
Q

describe the function of carbohydrate metabolism in the liver

A

insulin stimulates glycogenesis

adrenaline stimulates gluconeogenesis or glycogenolysis

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9
Q

describe the function of deamination of excess amino acids in the liver

A

deaminate AA and => ammonia (toxic) => urea

urea excreted by kidneys

remainder AA is used in respiration

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10
Q

what is transamination

A

conversion of an AA into another

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11
Q

describe the function of detoxification in the liver

A

> liver contains catalase (for hydrogen peroxide)

> and alcohol dehydrogenase
to ethanol => ethanal => ethanoate used to build fatty acids or used in respiration

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12
Q

what are the kidneys involved in

A

excretion

osmoregulation

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13
Q

what is the kidney’s function

A

filter nitrogenous waste products out the blood

maintain water balance

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14
Q

what vein carries blood coming out the kidney

A

renal vein

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15
Q

what is the kidney made up of

what do they act

A

nephrons

as filtering units

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16
Q

where does urine leave the kidneys

A

ureter

17
Q

how much urine can be stored in the bladder

A

400-600 cm^3

18
Q

where does the urine leave the body from

A

urethra

19
Q

give the structure of the kidney

A

cortex (dark outer layer)
filtering of blood takes place
dense capillary network

medulla (lighter inner layer)
contains tubules of nephrons that forms the pyramids and the collecting ducts

pelvis
where urine collects before leaving

20
Q

how long is a nephron

how many nephrons in a kidney

A

3cm

1.5 million nephrons

21
Q

give the structure and function of the bowman’s capsule

A

cup-shaped containing the glomerulus

blood goes into the glomerulus to go into ultrafiltration

22
Q

give the structure and function of the proximal convoluted tubules

A

coiled region of the tubule
in the cortex

where substances needed are reabsorbed into the blood

23
Q

what does the loop of henle do

A

tubule that creates a [high solute] in the medulla as tissue fluid

24
Q

give the structure and function of the distal convoluted tubule

A

second twisted tubule where water balance maintenance takes place

ADH action is here

further ion + blood regulation is here too

25
Q

what is the structure and function of the collecting duct

A

urine passes down the collecting duct in the medulla to the pelvis

fine tuning of water balance takes place here

(ADH action here)

26
Q

what should the concentration of urea, glucose and amino acids be like when the blood leaves the kidney

A

urea = greatly reduced

glucose + AA = the same

27
Q

describe ultrafiltration

A

process that results in the formation of tissue fluid in the capillary beds of the body

28
Q

which arteriole is wider in the kidney

what does it cause

A

afferent

pressure builds up forcing blood through capillary wall

29
Q

describe the basement membrane

A

made up of network of collagen fibres + other fibres

blood cells and proteins are retained in the capillary

30
Q

describe podocytes

A

form pedicels that wrap around capillaries forming slits and make sure large substances go through epithelial cells

31
Q

what is the ultrafiltrate

A

hypotonic (less conc. than) to blood plasma

32
Q

what happens in the PCT

A

large substances are moved back into the blood by active transport

85% of NACl + water reabsorbed

33
Q

what are the adaptations of the PCT

A

covered with microvilli

many mitochondria

34
Q

what is the filtrate reaching the loop of henle

A

isotonic (same conc) with tissue fluid and blood

35
Q

what happens at the loop of henle

A

different areas of the loop have different permeabilities to water

acts as a countercurrent multiplier

36
Q

what happens in the descending limb

A

water moves out filtrate down gradient
(lower part)

conc of ions increases due to activity of ascending limb

filtrate entering descending limb is isotonic with blood
as it travels down, water passes out the loop by osmosis into the blood

descending limb impermeable to ions, so no active transport

fluid reaching the bend is hypertonic to blood

37
Q

what happens in the ascending limb

A

the 1st section is permeable to ions and they move out by diffusion

in the 2nd section, ions are actively pumped into medulla tissue fluid

producing high [ion] in medulla

ascending limb is impermeable to water
so fluid in the limb is dilute while tissue fluid is very conc.

by the time the fluid reaches the top of the ascending limb, it is hypotonic to blood, and enters the distal convoluted tubule

38
Q

what happens at the distal convoluted tubule

A

water balance takes place

contains many mitochondria

if the body lacks salt, ions are pumped out the DCL

39
Q

what do desert animals have more of in the kidneys

A

longer

biology (15 decks)

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