kidneys Flashcards
how is the kidney adapted for its function (not on a cellular level)
It has a good blood supply by efferent and afferent arterioles so it is able to maintain steep concentration gradients.
different sized blood vessels enter and level the glomerulus which means a pressure gradient can be established forcing filtrate out of the blood (such as glucose, a.a, small hormones and oxygen - not RBC or proteins).
it has a layer of fat which protects is against mechanical damage.
loop of henle has a counter current multiplier which maximises the concentration gradient as fluid flows in opposite directions in two vessels.
podocytes and basement membrane (ULTRAFILTRATION)
how would an infection of the basement membrane leading to kidney failure cause protein to be found in urine.
Damage to podocytes which act as a filtrate mechanism in the basement membrane means that proteins can fit through the membrane and enter the bowman’s capsule and ensure proximal convoluted tubule, the proteins cannot be reabsorbed into the blood so they remain in the urine until they are excreted from the body as urine.
what role does the proximal convulated tubule do in the kidney
It actively transports glucose, a.a and mineral ions out of the blood (80%) this increases the water potential so water follows by active transport.
what happens in the descending loop of henle
water moves out of the loop of henle by osmosis and into the medulla. Na+ ion and K+ ions move into the loop of henle down the concentration gradient by diffusion. this causes a hypertonic water potential to be achieved (the water is salty) at the hair pin.
what are some differences between haemodialysis and peritoneal
haemo has a countercurrent mechanism which means that countercurrent it has a steeper concentration gradient then peritoneal which reaches eqm with the blood.
peritoneal can perform active transport and facilitated diffusion due to channel proteins.
what happens in the ascending loop of henle
salts are actively transported outwards
give similarities and differences between the formation of urine and the formation of tissue fluid.
similarities
- larger molecules remain in the blood
- both involve a basement membrane
- smaller molecules are reabsorbed back into the blood
- takes place because there is a greater hydrostatic pressure then oncotic pressure
- takes place in the capillaries
differences
- filtrate enters the bowman’s capsule. the tissue fluid surrounds cells
- molecules not absorbed in the kidney form urine, molecules not absorbed in the tissue fluid form the lymph
- blood is filtered through 3 layers in the kidneys ie podocytes, endothelium gaps and basement membrane where as tissue fluid is through one membrane
- glumerlus is a knot of capillaries where as there is a network of capillaries in the formation of tissue fluid
what is GFR and how is it measured
(GFR) provides an indication of the health of their kidneys. The GFR is a measure of the volume of blood that can be filtered by the kidneys every minute. GFR can be estimated by monitoring the blood concentration of creatinine, which is a breakdown product of creatine phosphate in muscles.
Suggest some characteristics of a patient that must be taken into account when using this GFR measurement to diagnose kidney damage.
- age, kidney functioning declines with age
- gender, men and women have different muscle masses
- activity levels and biomass because this will alter production of creatinine
- diet alters cretanine
how can hCG hormone be detected in pregnancy tests
this is because hCG has a molecular mass of less than 69,000
Damage to the hypothalamus results in lower water potential of the blood. why
ADH release increases the water potential of blood. Fewer water channels are inserted into the cell surface membranes of the collecting duct
Explain why podocytes are usually unable to undergo mitosis.
they are already specialised
they have irregular shape so they cannot form spindle fibres
What features of adult stem cells make them suitable for regeneration of tissues in the kidney?
(adult stem cells) are multipotent ✔
(differentiate to) become any cell type within, kidney / nephron (tissue) ✔
what does the DCT do
(re)absorption / regulation, of (named) ions ✓Cl- / K+ / Na+ / Ca2+
(re)absorbs water
regulation of pH
describe how salted crisps and boiled sweets affect urine.
then show how bread, milk and chocolate affect urine.
salted crisps AND boiled sweets reduce water potential of blood (because of high sugar / salt content) ✓
osmoreceptors in hypothalamus, detect change in water potential in blood / cause increased release of ADH ✓
ADH causes production ofaquaporins in collecting duct so more water is reabsorbed (into capillaries) ✓
bread / milk / chocolate, increase water potential of blood ✓
causes reduced ADH release
✓
