kidney Flashcards
where does blood enter the capillary?
through the renal artery
where does ultrafiltration take place?
in the bowmans capsule
how is the kidney adapted to ultrafiltration?
the afferent is bigger than the efferent so a high pressure is maintained
lined with epithelium for an extra layer/barrier to larger molecules
basement membrane also included
where/when does selective reabsorption take place?
PCT, loop of henle and DCT
where do the useful substances go once they have left the PCT, loop of henle and DCT?
back into the surrounding capillary network
how is the PCT adapted for reabsorption?
epithelium of walls has microvilli to increase SA
how are useful substances reabsorbed into the capillaries along the PCT?
active transport and facilitated diffusion
what substances are reabsorbed into the blood?
glucose
amino acids
vitamins
what equipment is needed when dissecting a mammals kidney?
mammals kidney
apron
scalpel
lab gloves
dissecting tray
control of water potential (without hormones)
ascending limb is impermeable to water so water stays in and NA+ and Cl- ions are actively pumped out
water moves out of the descending limb and is reabsorbed into the capillary network
near the bottom of the loop of henle ions diffuse out further lowering the water potential (walls are impermeable to water so it stays in the tubule)
due to high conc of water, it leaves the collecting duct via osmosis
how is water regulated by hormones?
osmoreceptors in the hypothalamus detect the change in WP
a nerve impulse is sent to the posterior pituitary gland to secrete more/less ADH
ADH makes the DCT and the collecting duct more permeable to water
how can we detect kidney failure
measure the glomerular filtrate rate
problems associated with kidney failure (4)
waste products building up in the blood (weight loss and vomiting)
fluids accumulate in tissues (parts of the body begin to swell)
unbalance ions could cause blood to become too acidic
anaemia
3 methods of treating kidney failure
haemodialysis
kidney transplant
peritoneal dialysis
haemodialysis
filter a patients blood from an artery by having their blood flow on one side of a partially permeable membrane and the dialysis fluid on the other side
waste products (excess urea and mineral ions) and excess water diffuse across the membrane and into the dialysis fluid
the blood and dialysis fluid flow in opposite directions
what are two main issues involved in haemodialysis
patient may feel unwell as waste products and fluid start to build up in their blood
expensive and inconvenient (2/3 sessions a week for 8 hours long)
kidney transplant
same blood and tissue type
advantages of transplants (3)
cheap
more convenient (less sessions)
patients wont feel unwell between/during sessions
disadvantages of kidney transplant (2)
major operation
immune system could reject the new transplant -immunosuppressants could be used but would give the patient a low immune system
what hormone is present in urine of a pregnant women?
hCG (human chorionic gonadotropin)
if hCG is present?
hCG would bind to the monoclonal antibodies at the end of the stick which contain a blue dye,
the monoclonal antibodies move along the stick and would bind to the immobilised enzymes turning the test strip blue
if no hCG is present?
the urine moves along the pregnancy test strip without binding to anything so no colour appears
why can urea but not glucose and a typical amount of mineral ions leave the patients blood during a dialysis session?
the dialysis fluid contains no urea, normal plasma levels of glucose and mineral ions so there is no net movement of them
peritoneal dialysis
is done inside of the body and used the lining of the abdomen
usually done at home
a catheter enters the abdomen
urea and excess mineral ions leave into the tissue fluid, out across the peritoneal membrane and into the dialysis fluid
