Excretion

Question 1

what is excretion?

Answer 1

process of removing metabolic waste products from the body

Question 2

What are examples of waste products in the body? How are each produced?

Answer 2

CO2- produced during respiration

Bile- produced when haemoglobin broken down

nitrogenous waste- produced when amino acids broken down

Question 3

What are the three blood vessels in the liver?

Answer 3

Hepatic artery
Hepatic vein
Hepatic portal vein

Question 4

Role of Hepatic artery?

Answer 4

Provide oxygenated blood has nutrients from the heart

Question 5

Role of Hepatic vein?

Answer 5

moves deoxygenated blood out of liver to the heart

Question 6

Role of Hepatic portal vein?

Answer 6

moves deoxygenated blood , nutrient filled, from digestive system

Question 7

The liver is the main organ used in the excretory system, what cells make up the liver?

Answer 7

Hepatocytes

Question 8

What capillary surrounds hepatocytes?

Answer 8

sinusoids , connected to hepatic artery, hepatic vein and central vein

Question 9

name 3 functions of the liver?

Answer 9

1. stores glycogen needed to regulate blood glucose levels
2. break down toxic substances Ie: alcohol through detoxification
3. break down access amino acids through deamination

Question 10

how are amino acids broken down through deamination? what product is made?

Answer 10

1. amine group remove from amino acid by deamination
2. amine group converted into ammonia
3. ammonia too toxic for body, so combined with carbon dioxide to produce urea
4. urea excreted via urine out the body

remainder of amino acids used for respiration

Question 11

what cycle is used when ammonia combined with co2 to produce urea?

Answer 11

ornithine cycle

Question 12

what is the role of the kidney?

Answer 12

filter the blood to make urine through getting rid of excretory products, like urea

Question 13

what is the main structure of the kidney that produces urine?

Answer 13

nephron

Question 14

what makes up the nephron in the correct order?

Answer 14

1. afferent arteriole snd efferent arteriole
2. glomerulus
3. Bowmans capsule
4. proximal convoluted tubule
5. loop of henle
6. distal convoluted tubule
7. collecting duct

Question 15

what is the difference between the afferent and efferent arterioles? what do they cause?

Answer 15

lumen size - afferent has a larger lumen

creates filtrate pressure in glomerulus forcing substances out

Question 16

what does the hormone ADH do?

Answer 16

controls permeability of collecting duct wall

Question 17

why is the efferent arteriole wrapped around the whole nephron?

Answer 17

needed for selective reabsorption of useful materials

Question 18

what happens if there is more ADH

Answer 18

more ADH = more permeable the wall = more water reabsorbed

Question 19

what is osmoregulation?

Answer 19

regulation of blood water levels

Question 20

explain selective reabsorption in the nephron

Answer 20

1. proximal convoluted tubule - all glucose, amino acids, vitamins and hormones reabsorbed by active transport
   - some sodium ions also reabsorbed by active transport
   - movement of sodium ions changes water potential
   - leads to water being reabsorbed by osmosis , which causes filtrate to now be more concentrated
   - chloride ions leave by diffusion to be reabsorbed now
2. loop of henle
   - water continues to be reabsorbed
   - move down depending limb, ion concentration increases
3. hypertonic point reach at bottom of decending limb and ascending limb, meaning a very high salt conc
   - causes salt to be easily reabsorbed by diffusion
4. ascending limb
   - conc of salt decreases in filtrate
   - isotonic level reached where salt level inside and out of nephron the same
   - causes more salt to be reabsorbed by active transport
5. distal convulated tubule
   - salt, water reabsorbed if the body needs it
   - water if needed absorbed via ADH
   - anything reabsorbed to balance salt and water level and to regulate blood ph level
6. collecting duct
   - water reabsorbed by ADH and osmosis
   - as go down collecting duct , cells can change the conc of salt in tissue fluid, causing a steep water concentration gradient
   - ADH tells tubule wall more aquaporins needed for more water reabsorption

Question 21

what is used in ultrafiltration in the nephron?

Answer 21

afferent and efferent arteriole
endothelium cell wall
basement membrane
bowsman capsule
podocytes
peducils

Question 22

what are podocytes , role?

Answer 22

on Bowmans capsule cell wall acting as second filter
contain peducils preventing large molecules like RBC entering filtrate

Question 23

what detects the change in water potential in the blood?

Answer 23

osmoregulators

Question 24

where are the osmoregulators in the body?

Answer 24

hypothalamus

Question 25

where is ADH produced and where is it released?

Answer 25

produced in hypothalamus related in pituitary gland

Question 26

what are two treatments used to treat kidney failure?

Answer 26

kidney dialysis and kidney transplant

Question 27

how is kidney failure determined?

Answer 27

through glomerular filtration rate if falls below 15

Question 28

what are the two types of kidney dialysis ?

Answer 28

haemmodialysis peritaneal

Question 29

explain haemodialysis for kidney dialysis

Answer 29

patients blood taken from their artery and passed through dialysis machine to remove harmful molecules and adjusts the chemicals - ions and water - in blood to normal ranges blood returned to patients vein

Question 30

what role of the Bowmans capsule does the renal dialysis take?

Answer 30

basement membrane forming a partially permeable membrane

Question 31

what is peritoneal dialysis?

Answer 31

abdominal cavity filled with dialysis fluid from catheter

Question 32

in peritoneal dialysis what is the abdominal cavity surrounded by?

Answer 32

peritoneum membrane acting as filter

Question 33

disadvantages of haemodialysis?

Answer 33

3x week at hospital several hours restricted diet

Question 34

pros of peritoneal dialysis

Answer 34

done at home frequent so molecules in blood kept stable

Question 35

how does diagnostic testing work? what does it use?

Answer 35

works through using urine samples, to test chemicals in the urine to diagnose medical conditions

Question 36

what hormone is produced in pregnancy which used to test whether someone is pregnant?

Answer 36

hCG

Question 37

what antibody is used to test for the presence of hCG in the urine?

Answer 37

monoclonal antibodies

Question 38

describe the steps with how monoclonal antibodies for hCG produced

Answer 38

1. mouse injected with hCG 2. b lymphocytes extracted from spleen of mouse (some of the antibodies produced against hCG) 3. b lymphocytes have a short life span so fused with cancer cell - myeloma producing hybridoma cells 4. only some hybridoma cells produce antibodies against hCG 5. hybridoma cells screened - identifying what cells produce antibodies against hCG 6. correct cell found , cultured to produce millions of copies of original hybridoma 7. antibodies to hCG purified

Question 39

describe how a pregnancy test works

Answer 39

1. place end of wick into urine in the morning, morning will contain highest conc of hCG 2. wick contains monoclonal antibodies to hCG 3. antibodies bind to hCG forming hCG Antibody complex 4. urine and antibodies make way up wick 5. at certain point on wick will contain immobilised antibodies which cannot move 6. immobilised antibodies bind to hCG antibody complex 7. beads form pink strip across wick if pregnant 8. some antibodies did not bind to hCG , so the unbound antibodies continue to move up strip 9. further up wick another line of immobilised antibodies forming second pink strip which is the control strip telling us whether the test working or not