further synthetic routes Flashcards
hepatocytes
liver cells
why is there a good blood supply to the liver
thi enables the liver cells to remove excess or unwanted substances from the blood
what are the two supplies of blood to the liver
the hepatic artery
the hepatic portal vein
what is the hepatic artery
carries oxygenated blood from the heart to the liver in order to supply oxygen for respiration
what is the hepatic portal vein
carries deoxygenated blood fro, the digestive system i order to be filtered of toxic and useful products
hepatic vein
the vessel through which blood leaves the liver
bile duct
carries bile from the liver to the gall bladder where it is stored untill required to aid digestion of fats in the small intestine
what is bile
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
how are the vessels and chambers inside the liver aranged to ensure the greatest possible contact between the blood and the liver cells
liver is divided into lobes which are further divided into lobules. the lobulea are cylindrical
what are inter lobular vessels
hepatic artery and portal vein split into smaller and smaller vessels. these run between and parallel to the lobules
what is a sinusoid
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
what are kupffer cells
these are cells that move about within sinusoids and recycle old red blood cells
where does blood go after the sinusoid
intra lobular vessels:
the branches of hepatic vein from different lobules join together to form hepatic vein, which drains blood from the liver.
why is the cytoplasm of liver cells very dense
their many metabolic functions include:
protein synthesis, transformation and storage of carbohydrates,
synthesis of cholesterol and bile salts,
detoxification
define ornithine cycle
a series of biochemical reactions that convert ammonia to urea
what are the metabolic functions of the liver
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
what are examples of enzymes that render toxic molecules less toxic
catalase
cytochrome P450
how is alcohol broken down by hepatocytes
by action of the enzyme ethanol dehydrogenase. the resulting compound is ehtanal which is dehydrogenised further to ethanoate
what causes fatty liver
alcohol uses up its stores of NAD and has insufficient left to deal with the fatty acids
the ornathene cycle
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
define nephron
the functional unit of the kidney
define ultrafiltration
filtration of the blood at a molecular level under pressure
what is the cortex of the kidney
the outer region
what is thw medulla of the kidney
the inner region
what is the difference between affverent and efferent arteriones
afferent goes in efferent leaves
how is the endothelium of the capillary adapted to ultrafiltration
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
how is the basement membrane adapted to ultrafiltration
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
how are epithelial cells of the bowmans capsule adapted to ultrafiltraton
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
what is reabsorbed at the proximal convoluted tubule
all sugars
most mineral ions
some water
85% of all fluids reabsorbed
what happens to water potential at the decending limb of the loop of henle
water potential of the fluid is decreaced by addition of mineral ions and removal of water
what happens to water potential at the acending limb of the loop of henle
water potential is increaced as mineral ions are removed by acive transport
what happens to water potential at the collecting duct
water potential is decreaced again by the removal of water.
what is the overall purpose of the loop of henle
to create a water potential gradient
antidiuretic hormone(ADH)
a hormone that controls the permeability of the collecting duct walls
osmoreceptor
a sensory receptor that detects changes in water potential
how does ADH control permeability of the collecting duct
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.
Define glomerular filtration rate
the rate at which fluid enters the nephrons
monoclonal antibodies
antibodies made from one type of cell, they are specific to one complimentary molecule
renal dialysis
a mechanism used to artificially regulate the concentrations of solutes in the blood
what are the main treatments for kidney failure
renal dialysis and kidney transplant
haemodialysis
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
peritoneal dialysis
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
