further synthetic routes

Question 1

hepatocytes

Answer 1

liver cells

Question 2

why is there a good blood supply to the liver

Answer 2

thi enables the liver cells to remove excess or unwanted substances from the blood

Question 3

what are the two supplies of blood to the liver

Answer 3

the hepatic artery
the hepatic portal vein

Question 4

what is the hepatic artery

Answer 4

carries oxygenated blood from the heart to the liver in order to supply oxygen for respiration

Question 5

what is the hepatic portal vein

Answer 5

carries deoxygenated blood fro, the digestive system i order to be filtered of toxic and useful products

Question 6

hepatic vein

Answer 6

the vessel through which blood leaves the liver

Question 7

bile duct

Answer 7

carries bile from the liver to the gall bladder where it is stored untill required to aid digestion of fats in the small intestine

Question 8

what is bile

Answer 8

a secretion from the liver which has functions in digestion and excretion.
also contains excretory product such as bile pigments which leave the body through feaces

Question 9

how are the vessels and chambers inside the liver aranged to ensure the greatest possible contact between the blood and the liver cells

Answer 9

liver is divided into lobes which are further divided into lobules. the lobulea are cylindrical

Question 10

what are inter lobular vessels

Answer 10

hepatic artery and portal vein split into smaller and smaller vessels. these run between and parallel to the lobules

Question 11

what is a sinusoid

Answer 11

branches from the hepatic artery and the hepatic portal vein enter the lobules the blood from the two vessels are mixed and are passed along a sinusoid

Question 12

what are kupffer cells

Answer 12

these are cells that move about within sinusoids and recycle old red blood cells

Question 13

where does blood go after the sinusoid

Answer 13

intra lobular vessels:
the branches of hepatic vein from different lobules join together to form hepatic vein, which drains blood from the liver.

Question 14

why is the cytoplasm of liver cells very dense

Answer 14

their many metabolic functions include:
protein synthesis, transformation and storage of carbohydrates,
synthesis of cholesterol and bile salts,
detoxification

Question 15

define ornithine cycle

Answer 15

a series of biochemical reactions that convert ammonia to urea

Question 16

what are the metabolic functions of the liver

Answer 16

control of blood glucose levels, amino acid levels , lipid levels

synthesis of bile, plasma proteins , cholesterol

synthesis of red blood cells in the fetus

storage of vitamins A, D andB12, iron, glycogen

detoxification of alcohol, drugs

breakdown of homones

destruction of red blood cells

Question 17

what are examples of enzymes that render toxic molecules less toxic

Answer 17

catalase
cytochrome P450

Question 18

how is alcohol broken down by hepatocytes

Answer 18

by action of the enzyme ethanol dehydrogenase. the resulting compound is ehtanal which is dehydrogenised further to ethanoate

Question 19

what causes fatty liver

Answer 19

alcohol uses up its stores of NAD and has insufficient left to deal with the fatty acids

Question 20

the ornathene cycle

Answer 20

ammonia and carbon dioxide combine with ornithine to produce citruline. this is converted to argenine by addition of further ammonia. the argenine is converted to ornithine by the removal of urea

Question 21

define nephron

Answer 21

the functional unit of the kidney

Question 22

define ultrafiltration

Answer 22

filtration of the blood at a molecular level under pressure

Question 23

what is the cortex of the kidney

Answer 23

the outer region

Question 24

what is thw medulla of the kidney

Answer 24

the inner region

Question 25

what is the difference between affverent and efferent arteriones

Answer 25

afferent goes in efferent leaves

Question 26

how is the endothelium of the capillary adapted to ultrafiltration

Answer 26

there are narrow gaps between the cells of the endothelium of the capillary wall.there are also pores called fenestrations that allow blood plasma and the substances dissolved in it to pass out the capillary

Question 27

how is the basement membrane adapted to ultrafiltration

Answer 27

consists of collagen fibres and glycoproteins and acts as a filter that only allows molecules of molecular mass greater than 69000 so most proteins and rbc are kept in the capillaries

Question 28

how are epithelial cells of the bowmans capsule adapted to ultrafiltraton

Answer 28

podocytes: have many finger like projections holds cells away from capillary endothelium these ensure there are gaps between the cells so fluid from the blood in the glomerulus can pass throuhg

Question 29

what is reabsorbed at the proximal convoluted tubule

Answer 29

all sugars most mineral ions some water 85% of all fluids reabsorbed

Question 30

what happens to water potential at the decending limb of the loop of henle

Answer 30

water potential of the fluid is decreaced by addition of mineral ions and removal of water

Question 31

what happens to water potential at the acending limb of the loop of henle

Answer 31

water potential is increaced as mineral ions are removed by acive transport

Question 32

what happens to water potential at the collecting duct

Answer 32

water potential is decreaced again by the removal of water.

Question 33

what is the overall purpose of the loop of henle

Answer 33

to create a water potential gradient

Question 34

antidiuretic hormone(ADH)

Answer 34

a hormone that controls the permeability of the collecting duct walls

Question 35

osmoreceptor

Answer 35

a sensory receptor that detects changes in water potential

Question 36

how does ADH control permeability of the collecting duct

Answer 36

ADH binds to receptors and causes a chain of enzyme controlled reactions inside the cell. the end result of these reactions is to cause vesicles containing water permeable channels to fuse with the cell surface membrne.

Question 37

Define glomerular filtration rate

Answer 37

the rate at which fluid enters the nephrons

Question 38

monoclonal antibodies

Answer 38

antibodies made from one type of cell, they are specific to one complimentary molecule

Question 39

renal dialysis

Answer 39

a mechanism used to artificially regulate the concentrations of solutes in the blood

Question 40

what are the main treatments for kidney failure

Answer 40

renal dialysis and kidney transplant

Question 41

haemodialysis

Answer 41

blood from an artery or vein are passed into a machine that contains arteficil dialysis membrane shaped to form arteficial capillaries. dialysis fluid flows in the opposite direction to blood

Question 42

peritoneal dialysis

Answer 42

dialysis membrane is the bodies own abdominal membrane. tube is implanted in abdomen dialysis solution is poured through the tube and fills space between abdominal wall and organs