excretion

Question 1

what are the main metabolic waste products in mammals

Answer 1

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

Question 2

what are the adaptations of the liver

Answer 2

rich blood supply

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

Question 3

where does the hepatic portal vein carry blood from

Answer 3

contains products of digestion from intestines

Question 4

what is the structure of a hepatocyte

Answer 4

large nucleus

prominent golgi body

lots of mitochondria

Question 5

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

what does this do

Answer 5

sinusoids

increases oxygen content

Question 6

what do sinusoids contain

what is their function

Answer 6

kupffer cells

act as resident macrophages, ingesting foreign particles

Question 7

where do hepatocytes secrete bile into

Answer 7

spaces called canaliculi

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

Question 8

describe the function of carbohydrate metabolism in the liver

Answer 8

insulin stimulates glycogenesis

adrenaline stimulates gluconeogenesis or glycogenolysis

Question 9

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

Answer 9

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

urea excreted by kidneys

remainder AA is used in respiration

Question 10

what is transamination

Answer 10

conversion of an AA into another

Question 11

describe the function of detoxification in the liver

Answer 11

> liver contains catalase (for hydrogen peroxide)

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

Question 12

what are the kidneys involved in

Answer 12

excretion

osmoregulation

Question 13

what is the kidney’s function

Answer 13

filter nitrogenous waste products out the blood

maintain water balance

Question 14

what vein carries blood coming out the kidney

Answer 14

renal vein

Question 15

what is the kidney made up of

what do they act

Answer 15

nephrons

as filtering units

Question 16

where does urine leave the kidneys

Answer 16

ureter

Question 17

how much urine can be stored in the bladder

Answer 17

400-600 cm^3

Question 18

where does the urine leave the body from

Answer 18

urethra

Question 19

give the structure of the kidney

Answer 19

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

Question 20

how long is a nephron

how many nephrons in a kidney

Answer 20

3cm

1.5 million nephrons

Question 21

give the structure and function of the bowman’s capsule

Answer 21

cup-shaped containing the glomerulus

blood goes into the glomerulus to go into ultrafiltration

Question 22

give the structure and function of the proximal convoluted tubules

Answer 22

selective reabsorption

Question 23

what does the loop of henle do

Answer 23

lowers water potential of medulla tissue

Question 24

give the structure and function of the distal convoluted tubule

Answer 24

osmoregulation

Question 25

what is the structure and function of the collecting duct

Answer 25

urine passes down the collecting duct in the medulla to the pelvis fine tuning of water balance takes place here (ADH action here)

Question 26

describe ultrafiltration

Answer 26

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

Question 27

which arteriole is wider in the kidney what does it cause

Answer 27

afferent pressure builds up forcing blood through capillary wall

Question 28

describe the basement membrane

Answer 28

made up of network of collagen fibres + other fibres blood cells and proteins are retained in the capillary

Question 29

describe podocytes

Answer 29

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

Question 30

what is the filtrate reaching the loop what would this make

Answer 30

isotonic very dilute urine

Question 31

what are the adaptations of the PCT

Answer 31

covered with microvilli many mitochondria (for AT) infoldings near the blood capillary

Question 32

what is the filtrate reaching the loop of henle

Answer 32

isotonic (same conc) with tissue fluid and blood

Question 33

what does the loop of henle act as

Answer 33

countercurrent multiplier

Question 34

what do desert animals have more of in the kidneys

Answer 34

longer

Question 35

compare the descending limb and ascending limb

Answer 35

descending = thin walled, permeable to water ascending = thick walled, impermeable to water

Question 36

what is the process of osmoregulation in the loop of henle

Answer 36

in ascending limb: 1. ions pumped out to interstitial region 2. medulla has lower WP as descending limb moves down: 1. water moves out by osmosis 2. bottom of the loop is hypertonic 3. when filtrate goes up, ions can passively diffuse out 4. when it's further up, ions pumped out this means less energy is required to remove ions out the filtrate

Question 37

describe the counter-current multipler

Answer 37

refers to the fact filtrate moves down the descending limb and up ascending limb (counter-current) and efficiency of ion transfer is amplified by water moving out the descending limb (multiplier)

Question 38

where does ultrafiltration occur

Answer 38

molecules filtered out blood through glomerulus

Question 39

what parts of the nephron are in the medulla

Answer 39

loop of henle and collecting duct

Question 40

how does glucose reabsorption work in the PCT

Answer 40

1. AT of Na+ into the blood 2. carries away by blood 3. epithelial cells have low conc of Na+ 4. Na+ diffuse into epithelial cells through carrier proteins 5. carrier proteins also transfer glucose (co-transport) 6. glucose diffuses into the blood

Question 41

what is peritoneal dialysis

Answer 41

inside the body excess materials pass out capillaries to the tissue fluid to the dialysis fluid through catheter

Question 42

describe the peritoneum

Answer 42

natural dialysis membranes formed by lining of abdomen (peitoneal membranes)