Kidneys Flashcards
what is the process that moves water from the collecting ducts into the medulla?
osmosis
what happens when less water is taken into the blood?
more is lost in the urine
what is the function of osmoreceptors?
they inhibit the release of ADH
what detects high/low water potential?
osmoreceptors
how is water potential raised back to normal level?
water is absorbed into the blood
what is the function of ADH?
it acts on collecting ducts to allow more water into the medulla
where is ADH released from?
posterior pituitary gland
where are osmoreceptors located?
in the hypothalamus
what is negative feedback for?
osmoregulation
what is a negative effect of ADH?
it allows urea to pass through aquaporins, reducing the water potential of the medulla
what is the function of aquaporins?
they increase the permeability of the collecting duct to water, so more can be reabsorbed
what is the function of phosphorylase?
vesicles containing aquaporins to move to the apical side of the cell
where does ADH bind to?
receptors on the collecting ducts and DCT
where does ADH in the blood travel to?
the kidneys - cells lining the collecting ducts of the nephron and DCT
what is the function of the kidney?
it regulates the amount of of urine produced to control the water potential of the blood
how is water lost from the body?
urine, sweating, breathing and excretion
what can happen to cells if water potential is too low?
they can shrink and change shape
how do the kidneys maintain water balance in the body?
by regulating the reabsorption and excretion of water via filtration and urine formation
what is the function of the nephrons?
filtering waste products and excess water from the blood and reabsorbing necessary substances
where does 85% of reabsorption occur?
PCT
what is reabsorbed?
glucose, amino acids, water and some ions
where is the filtrate produced?
from the glomerulus of capillaries and certain substances are from the blood into the filtrate
what is needed for reabsorption?
mitochondria to make ATP
how is the shape of the PCT designed to maximise reabsorption?
the coiled shape and microvilli increase surface area for protein pumps etc.
what does the PCT reabsorb?
water, urea, sodium, amino acids and glucose
what happens during secondary active transport?
the movement of glucose or amino acids rely on the active transport of sodium
why are sodium-potassium pumps needed?
they use ATP to pump sodium ions into the blood, creating a low cellular sodium concentration
how are larger proteins reabsorbed?
by endocytosis
why do blood cells and proteins stay in the capillaries?
they are too big and decrease the water potential
what is the 2nd layer in the Bowman’s capsule?
podocytes
what is ultrafiltration?
small molecules are filtered out the blood into the lumen of the capillaries in the Bowman’s capsule
what is hCG?
human chorionic gonadotrophin
what are in home pregnancy tests?
monoclonal antibodies with dye
what is on the control line?
immobilised complementary antibodies
what are urine tests used for?
information about a person’s hydration, kidney function, infections or disease and drug use
what are anabolic steroids?
a synthetic hormone that increases protein synthesis and muscle growth
what is gas chromatography used for?
it analyses if steroids are present or not
how does renal dialysis work?
filtering water products and excess fluid from the blood using a dialyser acting as an artificial kidney
what is heparin for?
to stop blood clotting in the machine
what is in dialysis fluid?
the right concentrations of minerals, urea, water etc.
what is peritoneal dialysis?
a tube is inserted in the peritoneum membrane (which is partially permeable) and fluid is inserted
what are risk factors for kidney failure?
diabetes, high blood pressure, family history, some medical conditions
what are the benefits of renal dialysis?
filters waste products and excess fluid from the body
what are the negatives of renal dialysis?
frequent treatments, complications such as infections
what is the PCT?
a series of loops which increase surface area
what is the function of the collecting duct?
reabsorbing water and concentrating urine
what is the function of the Bowman’s capsule?
filter blood and remove waste products in the kidneys
what is the function of the collecting duct?
osmoregulation
how is pH regulated?
in the DCT with H+
what does the descending limb do?
reabsorbs water from the filtrate
what does the ascending limb do?
reabsorbing sodium and chloride ions from the filtrate
