Excretion Flashcards
where does ultra filtration occur ?
Glomerulus / Bowman’s capsule
where does selective reabsorption occur ?
proximal convoluted tubule
where does water conservation occur (in nephron) ?
loop of Henle
where does osmo regulation occur in the nephron ?
distal convoluted tubule and collecting duct
what is reabsorbed in the proximal convoluted tubule ?
glucose, amino acids, vitamins and some salts
name the arteriole going into glomerulus
afferent arteriole
name the arteriole going out glomerulus
efferent arteriole
how is high hydrostatic pressure created in the glomerulus ?
lumen gets smaller (afferent compared to efferent)
state the ways the proximal convoluted tubule is adapted
- micro villi for SA
- sodium pump
- uses co transporter proteins
define excretion
removal of metabolic waste from the body
what are the 3 main roles of the liver ?
- breaks down excess amino acids
- breaks down harmful substances
- stores glycogen
why must excess amino acids be broken down ?
nitrogenous substances can’t be stored by the body (cause damage)
Describe how excess amino acids are broken down
- deamination to form ammonia + organic acids
- ammonia + CO2 in orithine cycle to form urea
what is deamination ?
removal of amine group from excess amino acids
what happens to the organic acids from deamination ?
can be respired for ATP or converted to carbohydrate and stored as glycogen
Describe the detoxification of alcohol
- broken down into ethanal
- then broken into acetic acid
give 3 examples of harmful substances that would be broken down
ethanol / paracetemol / insulin
what is the hepatic portal vein ?
brings blood from duodenum and ileum (parts of small intestine) to liver
what is carried through hepatic portal vein to liver ?
any harmful substances ingested
where is bile made / stored / transported ?
made - liver
taken to gall bladder by bile duct to be stored
goes into duodenum
what is in the middle of a hepatocyte ?
central vein that connects to hepatic vein
what are the capillaries called in hepatocytes ?
sinusoids
what are Kupffer cells and what do they do ?
- cells attached to walls of sinusoids
- remove bacteria and break down old erythrocytes
what are the tubes called that connect the bile duct to the central vein in a hepatocyte ?
canaliculi
which parts of nephron are in cortex ?
Glomerulus / PCT / DCT / some collecting ducts
which parts of nephron are in medulla ?
loop of Henle / some of collecting ducts
what is the counter current multiplier mechanism ?
mechanism that helps reabsorb water back into blood (in loop of Henle)
what cells monitor water potential of blood ?
osmoreceptors
what happens when osmoreceptors are stimulated ?
hypothalamus sends impulse to posterior pituitary gland - ADH released
how is kidney failure detected ?
measuring glomerular filtration rate (low rate is bad)
how can kidney infections cause kidney failure ?
- cause inflammation which can damage cells
- interferes with filtering / reabsorption
how can high blood pressure cause kidney failure ?
pressure too high for glomeruli capillaries to cope, so are damaged, allowing large molecules (proteins) to pass
what happens w/ kidney failure ?
- waste products build in blood
- kidneys can’t remove excess water from blood
- electrolytes in blood becomes unbalanced
- anaemia
how does renal dialysis treat kidney failure ?
- blood flows through tube anti parallel to dialysis fluid tube
- water products / ions / water diffuse into dialysis fluid
what are cons of renal dialysis ?
- patient feels unwell between sessions
- expensive and inconvenient
what are cons of kidney transplant ?
- risky major operation
- immune system may reject transplant so patient has to take drugs to suppress
what hormone do pregnancy tests detect ?
hCG (in pregnant women)
how is fatty liver caused by alcohol intake ?
- breakdown of ethanol uses NAD
- less available NAD for fatty acid resp
- fatty acids -> triglycerides (stored in hepatocytes)
state another name for central vein
intralobular vein
describe process of water conservation in loop of Henle
- salts pumped from asc limb into interstitial fluid
- water pot int decreases
- water moves out of des limb
- water enters (vasa recta) capillary
- water pot filtrate decreases
describe the effect of ADH on kidney
- ADH binds to membrane receptor of collecting ducts / DCT
- cAMP activated
- aquaporins form in side of plasma membrane
- permeability increased
describe how pregnancy tests work
- hormone binds to specific antibody
- antibody complex moves along
- A.C. binds w/ specific immobilised antibodies
- binding causes coloured line
- control antibodies - immob anti
- two lines is +ve
how are steroids tested for ?
gas chromatography + mass spectrometry
urine vaporized to separate substances - then identified w/ MS
how to test for recreational drugs ?
- test strip w/ antibodies that changes colour when drug binds
- then sent for GC + MS
