liver & excretion

Question 1

Define excretion

Answer 1

The removal of waste products from the body

Question 2

What does excretion maintain?

Answer 2

Metabolism also homeostasis for helping to keep the levels of certain substances in the blood, roughly constant

Question 3

Give an example of excretion (respiration)

Answer 3

Carbon dockside is a waste product of respiration too much in the blood is toxic, so it’s ready for the body by the lungs or gills which act as excretory organ

Question 4

What organ breaks down excess amino acids

Answer 4

the liver

Question 5

Why do amino acids need to be broken down and excreted?

Answer 5

Amino acids contain nitrogen in amino groups Nitrogenous substances can’t usually be stored by the body. This means excess amino acids can be damaging to the body therefore they must be used by the body (to make proteins) or broken down and excreted.

Question 6

Explain the first step of how amino acids are broken down in the liver

Answer 6

deamination
The nitrogen containing amino groups are removed from any excess amino acids, forming ammonia and organic acids

Question 7

Step two of the breakdown of amino acids

Answer 7

The organic acids can be respired to give ATP, or converted to carbohydrate and stored as glycogen

Question 8

What happens to ammonia?

Answer 8

Ammonia is too toxic for mammals to excrete directly, so it’s combined with CO2 in the authorised cycle to create your urea

Question 9

What happens to urea?

Answer 9

urea is released from the liver into the blood, the kidneys and filters the blood and remove the urea as urine, which is excreted from the body

Question 10

What is detoxification?

Answer 10

The liver breaks down other harmful substances like alcohol, drugs, and unwanted hormones into less harmful compounds that can be excreted from the body

Question 11

How is alcohol detoxified

Answer 11

Alcohol, a toxic substance that can damage cells is broken down by the liver into ethanal Which is broken down into a less harmful substance called acetic acid, Excess alcohol over a long period of time can lead to cirrhosis of the liver, This is when the cells of the liver die in score tissue blocks blood flow

Question 12

describe the hepatic artery

Answer 12

Supplies to live with oxygenated blood from the heart of the liver has a good supply of oxygen for respiration

Question 13

Describe the hepatic vein

Answer 13

Takes deoxygenated blood away from the liver

Question 14

What’s the hepatic portal vein?

Answer 14

Brings blood from the duodenum and ileum(Parts of the small intestine)so it’s rich in the products of digestion. This means any interested, harmful substances are filled it out and broken down straight away

Question 15

What’s the bile duct ?

Answer 15

Takes bile( a substance produced by the liver to emulsify fat )to the gallbladder to be stored

Question 16

What are liver lobules

Answer 16

Cylindrical structure is made of cells called hepatocytes arranged in rows radiating out from the centre

Question 17

What is the central vein?

Answer 17

Found in middle of each lobule, Connect the hepatic vein.
Many branches of the Hepatic artery, hepatic portal vein and bile duct are also connected to each lobule

Question 18

What is sinusoids?

Answer 18

Capillaries that connect the hepatic artery and the hepatic portal vein to the Central vein

Question 19

Describe the blood flow through the liver

Answer 19

blood runs through the sinusoids past the hepatocytes that remove harmful substances and oxygen from the blood the harmful substances are broken down by the hepatocytes it’s less harmful substances that renter the blood.
The blood runs to the central vein, and the central veins from all the lobules connect up form the hepatic vein

Question 20

What are kupffer cells?

Answer 20

Also attach the walls of sinusoids, they move bacteria and breakdown old red blood cells

Question 21

What’s the bile canaliculi ?

Answer 21

Tubes of bile secreted by hepatocytes, These tubes drain into the bile ducts, the bile ducts from all the lobules eventually connect up and leave the liver

Question 22

what detects kidney failure

Answer 22

glomerular filtration rate(GFR)

Question 23

what is glomerular filtration rate

Answer 23

the rate at which blood is filtered from the glomerulus into the bowman’s capsule, lower than normal =kidneys not working

Question 24

what can kidney failure be abused by, how?

Answer 24

-kidney infections- cause inflammation (swelling),damage cells, interferes with bowman’s capsule (filtration) and reabsorption in other parts of nephrons

-high blood pressure- can damage glomeruli. blood in glomeruli is already under high pressure but. the capillaries can be damaged if the pressure gets too high, meaning larger moods like proteins can get through walls into urine

Question 25

what are the problems caused by kidney failure

Answer 25

1)waste product build up
2)fluid accumulation (swelling)
2)unbalance of electrolytes(blood too acidic)
3)longer term kidney failure causes anaemia

Question 26

what happens as a result of electrolyte imbalance

Answer 26

blood may become too acidic, imbalance of calcium and phosphate can lead to brittle bones. salt build up may cause more water retention

Question 27

what are 2 treatments of kidney failure

Answer 27

1)renal dialysis
2)kidney transplant

Question 28

what is renal dialysis

Answer 28

a patients blood is filtered

Question 29

2 types of renal dialysis

Answer 29

HAEMODIALYSIS, PERITONEAL DIALYSIS

Question 30

Explain haemodialysis

Answer 30

patients blood is passed through dialysis machine, blood flows on one side of a partially permeable membrane and dialysis fluid flows on the other side.
waste products and chess water and ions diffuse across the membrane into the dialysis fluid,removing them from the blood . blood cells and larger molecules like proteins are prevented from leaving the blood.

Question 31

how long are each dialysis sessions, how many are needed?

Answer 31

3/5 hours, 2 to 3 sessions a week

Question 32

why might patients start to feel increasingly unwell between dialysis sessions

Answer 32

waste products and fluid start to build up in their blood

Question 33

explain peritoneal dialysis

Answer 33

• dialysis fluid is put through a tube that passes front he outside of a patients abdomen into their abdominal cavity. waste products diffuse out of the patients blood into the dialysis fluid across the peritoneum(the membrane lies the abdominal cavity). after some time the fluiddd is drained out via the tube.

Question 34

where when and how many times is peritoneal dialysis carried out

Answer 34

at patients home, serval times a day or in one long overnight session.

Question 35

problems with peritoneal dialysis

Answer 35

risk of infection around site of tube, no dialysis free days

Question 36

explain kidney transplants

Answer 36

new kidney implanted into patients body to replace with damaged one
form a person istg the same blood/tissue type, often donated by living relative , or people who have recently died(organ donor)

Question 37

disadvantages/advantages of kidney transplants

Answer 37

cheaper than dialysis, more conviniet than dialysis
major operation that’s risky, immune system may reject , drugs to suppress

Question 38

what do pregnancy tests detect (draw out steps of pregnancy test in notes)

Answer 38

human chronic gonadotropin (hCG), only found in urine of pregnant women