Module 5

Question 1

What is excretion?

Answer 1

Removal of waste products of metabolism from the body

Question 2

Function of the hepatic artery?

Answer 2

Supplies the liver with oxygenated blood from the heart

Question 3

Function of the hepatic vein

Answer 3

Takes deoxygenated blood away from the liver

Question 5

3 ways carbon dioxide is transported around the body

Answer 5

5% in solution in plasma as CO2, 10% combines with amino groups in Hb molecule, 85% hydrogen carbonate ions

Question 6

Consequences of carbon dioxide not being excreted

Answer 6

Formation of carbaminohaemoglobin which has lower affinity for oxygen than normal haemoglobin
Respiratory acidosis - drop in blood pH, headache, drowsiness, tremors

Question 7

What blood vessel does the hepatic artery come from?

Answer 7

Aorta

Question 8

What do lobules make up in the liver?

Answer 8

Lobes

Question 9

Where does the hepatic vein take dexoygenated blood out of the liver?

Answer 9

Vena cava

Question 10

What are the specialised epithelial cells in liver lobules called?

Answer 10

Hepatocytes

Question 11

Adaptation of hepatocytes

Answer 11

Lots of mitochondria, large nuclei for transcription

Question 12

What is in the centre of a lobule?

Answer 12

Central vein

Question 13

What are sinusoids?

Answer 13

Large, endothelium-lined spaces that blood passes through

Question 14

What are Kupffer cells?

Answer 14

They destroy worn out red blood cells, bacteria and foreign matter arriving from digestive tract

Question 15

Where do central veins in liver lobules lead to?

Answer 15

Hepatic vein

Question 16

Function of the bile duct in the liver

Answer 16

Takes bile to the gall bladder

Question 17

What is bile made from and what is it made by?

Answer 17

Made from breakdown of haemoglobin, secreted by hepatocytes

Question 18

What are bile canaliculi?

Answer 18

Spaces that carry bile to the bile ducts

Question 19

What is urea produced from?

Answer 19

Excess amino acids containing nitrogen

Question 20

2 processes that forms urea

Answer 20

Deamination - amino group from each amino acid removed and hydrogen added to make ammonia. The rest of the amino acid is converted to keto acids, and either enters the Krebs cycle or is stored as glycogen.

Ornithine cycle - ammonia converted into urea. CO2 and ammonia converted to carbamoyl phosphate, and eventually water is added to make urea

Question 21

Process of detoxification of ethanol

Answer 21

Alcohol broken down into acetic acid by alcohol dehydrogenase and aldehyde dehydrogenase, then enters the Krebs cycle

Question 22

What happens when blood glucose levels rise?

Answer 22

Insulin is released, which stimulates hepatocytes to convert glucose into glycogen

Question 23

What happens when blood glucose levels decline?

Answer 23

Hepatocytes convert glycogen back into glucose due to hormone glucagon

Question 24

What is cirrhosis?

Answer 24

Hepatocytes replaced by fibrous (scar) tissue, structure of blood supply is lost, increasing ammonia concentration

Question 25

First structure of a nephron

Answer 25

Bowman’s capsule - contains the glomerulus

Question 26

Second structure of a nephron

Answer 26

Proximal convoluted tubule - substance reabsorption

Question 27

Third structure of the nephron

Answer 27

Loop of Henle - creates a region with high solute concentration in the tissue fluid

Question 28

What is after the loop of henle in a nephron?

Answer 28

Distal convoluted tubule - fine tuning of the body’s water balance, regulation of ions and pH of blood

Question 29

Last part of the nephron

Answer 29

Collecting duct - urine passes down here, more water balancing takes place

Question 30

Function of the afferent arteriole?

Answer 30

Blood coming into the nephron

Question 31

Functions of the nephron

Answer 31

Ultrafiltration, selective reabsorption in the proximal convoluted tubule, reabsorption of water in the loop of Henle, reabsorption in distal convoluted tubule, collecting duct collecting urine and emptying into ureter

Question 32

Blood in capillaries separated from the lumen of the Bowman’s capsule by…

Answer 32

Endothelium, basement membrane, podocytes

Question 33

Function of basement membrane

Answer 33

Prevent large molecules passing through, made of collagen fibres and other proteins

Question 34

Function of podocytes

Answer 34

Additional filter - extensions called pedicels that wrap around capillaries forming slits that makes sure cells don’t get into the tubule

Question 35

What substances stay in the filtrate?

Answer 35

Urea, water, inorganic ions

Question 36

By what process does glucose move back into the blood?

Answer 36

Diffusion, cotransported with sodium

Question 37

Functions of the loop of Henle

Answer 37

Create high concentration of sodium ions and chloride ions in tissue fluid of the medulla

Question 38

Why does there need to be a high concentration of sodium and chloride ions in tissue fluid?

Answer 38

Allows water reabsorption from contents of nephron as they pass through collecting duct

Question 39

Why is there a counter-current system in the loop of Henle?

Answer 39

The solute concentration in ascending limb lower than descending, causes build up of salt concentration in surrounding tissues

Question 40

Which part of the loop of Henle is impermeable to water?

Answer 40

The ascending limb

Question 41

Function of the distal convoluted tubule

Answer 41

If the body lacks salt, sodium ions are actively pumped out of nephron into blood, can act as a collecting duct

Question 42

What controls permeability in the collecting duct?

Answer 42

ADH

Question 43

What is osmoregulation?

Answer 43

Control of water content of the body to match water requirements

Question 44

Where in the brain are osmoreceptors found?

Answer 44

Hypothalamus

Question 45

What other part of the brain is involved in osmoregulation apart from the hypothalamus?

Answer 45

Posterior pituitary gland

Question 46

What does ADH do in the collecting duct?

Answer 46

Makes aquaporins bind to membrane to act as water channels

Question 47

Is less or more ADH produced when water content of the blood is high?

Answer 47

Less

Question 48

What is haemodialysis?

Answer 48

Blood from the patient’s artery runs through tubes made of a semi-porous membrane which mimics the basement membrane. In the machine is a sterile substance made of water, sugars etc. Urea and salt will then flow out of the patient’s blood into the dialysis fluid through diffusion.

Question 49

What is peritoneal dialysis?

Answer 49

Catheter inserted into the peritoneum cavity and dialysis fluid passed in. Urea and mineral ions pass out the blood capillaries into the tissue fluid and out across the peritoneal membrane.

Question 50

Advantages of haemodialysis?

Answer 50

Done by trained health professionals who can fix it if anything goes wrong Don’t have to do it yourself Shorter amount of time and on fewer days than peritoneal dialysis

Question 51

Disadvantages of haemodialysis?

Answer 51

It causes you to feel tired on the day of the treatments Can cause problems like low blood pressure and blood clots Increases risk of blood stream infections

Question 52

Disadvantages of peritoneal dialysis?

Answer 52

Procedure may be hard for some people to do Increases risk of infection of the lining of the peritonitis

Question 53

Advantages of peritoneal dialysis?

Answer 53

More freedom than haemodialysis Doesn’t require as many food and fluid restrictions