excretion- the kidneys Flashcards
excretion is
the removal of metabolic waste products from the body
waste product found in the lungs
carbon dioxide
waste product found in the skin
sweat
what are the three main roles of the kidney
- removal of urea from the blood
- adjustment of ion ( salt) levels in the blood
- adjustment of water content of blood
what are the excretory products of the kidneys
urea, ions and water
how do they carry out their main functions
by filtering stuff out of the blood under high pressure, and then reabsorbing the useful things.
what is the end product
urine
process of ultrafiltration
- blood from the renal artery flows through the glomerulus
- a high blood pressure squeezes water, urea and ions and glucose out of the blood and into the bowmans capsule
- the membranes between the bowmans capsule and the blood vessels act like filters so big molecules (proteins) and blood cells aren’t squeezed out and stay in the blood.
what is the filtered liquid called after ultrafiltration
glomerular filtrate
process of selective reabsorption
after the glomerular filtrate enters the bowmans capsule, glucose is the first substance to be reabsorbed at the proximal convoluted tube.
- all the glucose is reabsorbed from the proximal convoluted tubule so that it can be used in respiration. This happens through active transport
- sufficient ions are reabsorbed, not the excess ones
why is it called selective reabsorption
because only a selective few substances are reabsorbed
water reabsorption process
water is reabsorbed from the collecting duct in different amounts depending on how much water the body needs at a time
why si water reabsorption important/ needed
because the water is needed for osmoregulation
once out of the nephron where does urine go
nephron
through ureter
down to the bladder where it is stored
released by urethra
what is urea
toxic waste product
