lec 8 homeostasis Flashcards
why must organisms maintain their internal environment?
most organisms fxn best under narrow range of internal conditions
organisms gain and lose water by..?
diffusion
organisms regulate solutes by…?
active transport
how do organisms maintain temperature?
exchange heat with environment
what is osmosis?
water moves passively along concentration gradients across semipermeable membrane
water concentration is influenced by..?
solute concentration
ex. high solute conc. means low water conc.
water and some solutes through the process of active transport, diffuse from a ____to ____ concentration
high to low
t/f solutes cannot be actively transported across a cell membrane
false, they can thru channel or carrier protiens
regulation of water and solutes is controlled by…?
kidneys
aside from regulating water and solutes, what is another function of the kidney? Provide an example
dispose of metabolic waste
eg.
-toxic byproduct of protein metabolism is ammonia
-liver turns ammonia–> urea
-urea carried to kidney + disposed in urine
what are 4 main functions of kidneys?
-control amt of water leaving via urine
-filter blood
-release excess solutes
-urea released in urine
what controls kidney function?
hormones
blood enters kidneys through..?
renal artery
functional unit of a kidney is called..?
nephron
specialized capillaries that renal artery branches into
glomerulus
tubule and collecting duct are made of which type of cell?
epithelial
explain how filtration in the kidneys work
(4 steps)
-blood enters thru renal artery
-blood enters glomerulus
-pressure forces water+solutes out of glomerulus
-water+solutes go to tubule–>collecting duct
explain the process of reabsorption in the kidneys
-some solutes pumped from collecting duct into kidney tissue
-causes water to flow out of duct (osmosis)
-urine more concentrated w/ waste+solutes
water that flows into the tubule+duct not only contain solutes and waste but also contain____ and ____?
sugars and amino acids
what happens to the sugars and amino acids found in the tubule and duct?
pumped back into blood by active transport
what is the basic goal of osmosis
equal concentration of FREE water molecules on either side of a semipermeable membrane
