excretion Flashcards
excretion
removal from the body of metabolic waste, toxic materials, and substances in excess of requirements
2 excretory products
- CO2: waste product of respiration
- urea: made from excess amino acids
how CO2 excreted
transported to lungs in plasma where it diffuses into air in alveoli and is breathed out
how urea is excreted
carried to kidneys in plasma where it is filtered and excreted dissolved in the form of urine
glomerulus
clump of blood capillaries which filters urea, glucose, water, and ions from the blood
nephron
selective reabsorption of
- all of the glucose
- most of the water
- some of the ions/salts
urine contains
- excess water
- excess salts
- urea
deamination
removal of nitrogen containing parts of excess amino acids to form urea
important to excrete urea because
becomes toxic if allowed to build up in the blood
assimilation of amino acids in liver
- useful amount is converted to proteins and some into plasma proteins which are released into the blood
- excess amino acids broken down into urea that’s released into the blood + carbohydrate that’s converted to glycogen + stored
deamination process
- excess amino acids can’t be stored so broken into two
- carbohydrate/fat that’s used for energy
- ammonia (NH3) which combines with CO2 to form urea
- carried to kidneys where it’s filtered and excreted as urine
renal artery
carries oxygenated blood with high urea concentration to kidney
renal vein
carries deoxygenated blood from kidney with low urea concentration
ureter
tube that runs from kidneys to bladder
urinary bladder
- elastic muscular bag
- temporarily stored urine
