excretion Flashcards
what is the definition of excretion?
the removal of waste products of metabolism
the E in mrs. gren
why does the body do excretion?
all living cells carry out metabolic reactions which also produce waste products
some waste products are toxic so the body removes them
why is carbon dioxide excreted?
respiration provides energy but also water and carbon dioxide which is toxic to cells
energy and water can be used but not co2
how is carbon dioxide excreted?
it diffuses into the blood and out the lungs
what is urea and where is it produced?
it is a waste product produced in the liver
where does urea come from?
it comes from the breakdown of excess proteins and amino acids
why is urea excreted?
too much in the blood is toxic
when the kidneys filter blood what do they remove?
- urea
- excess water and ions
what is urine?
a solution of waste products including urea, produced by the kidneys
what organ produces urine?
the kidneys
differences between urine and urea?
urea:
- produced by the liver, not a solution
urine:
- produced by the kidneys, solution
how is urea produced?
when you eat more than you need excess proteins/amino acids are broken down into
- carbohydrates
- compounds containing nitrogen
what is deamination?
the removal of the part of amino acids containing nitrogen to form urea
removal of the N from CHO N
describe the steps to produce urea
- protein in food is taken into the alimentary canal
- the protein molecules are broken down into amino acids during digestion
- the amino acids are absorbed into the bloodstream and taken into the liver through the hepatic portal vein
- amino acids that are needed are made into proteins in the liver or released into the blood to e assimilated by body cells
what are glomerulus?
when blood flows into the kidney through the renal artery, it divides to form many tiny coiled capillaries called glomerulus
