Excretion in Humans Flashcards
what are the three organs of excretion?`
the lungs, skin and kidneys
carbon dioxide comes out of the lungs from what?
respiring cells
what is excreted from the kidneys
urine
what does urine contain?
excess water, urea and salts
what is excreted from the skin as urine?
water and salts
what is urea?
amino acids
how is urea made?
in the liver from excess amino acids
what do the kidneys do?
adjust water levels and salt content in the blood
the kidney has two roles, in what?
excretion and osmoregulation
what is osmoregulation?
the body balancing the water coming in and out
what does the kidney do in osmoregulation?
adjust the amount of water excreted by urine
what is the renal artery’s role?
brings blood from the aorta at a high pressure
what does the renal vein do?
carries blood away from the kidney after urea and other substances have been removes to the vena cava
what is ultrafiltration?
the movement of small molecules from the blood into the kidney tubule (nephron) at a high pressure
what holds back big molecules like protein and blood cells from entering the bowman’s capsule
the capillary wall, basement membrane and wall of capsule
what is the name of the fluid which enters the bowman’s capsule
glomerular filtrate
why is most water reabsorbed by osmosis in the tubule?
there is a higher concentration of water in the filtrate than in the blood
when does the selective reabsorption of glucose happen by active transport happen?
the first coiled tubule
what controls the amount of water reabsorbed by the nephrons?
ADH
what does ADH do?
makes the wall of the nephrons more permeable so that more water can be absorbed
