function of the nephron Flashcards
where does ulterfiltration occour
the glomerulas
what is the artriole that takes blood into the glomerulas called
the efferent artriole
what is the glomerulas comprised of
capillaries
what are the glomerular capillaries made up of
epithelial cells with pores between them
what is formed in the glomerulas that allows ulterfiltration to occour
hydrostatic pressure is formed
how is this hydrostatic presure formed
the differance in size between the afferent artriole wich has a smaller diameter compared to the efferent atriole.
what does this hydrostatic pressure do
forces small water glucose and mineral ions into bomans capsual forming glomerular filtrate
what is the water, glucose and mineral ions known as when pushed out of pores
glomerular filtrate
what remains in the blood stream
blood cells and protiens
why do they reamain in the blood stream
they are too large
what do these large cells leave via
the efferent atriole
what occours after uterfiltration
selective reabsorbtion
where does selective reabsorbtion happen
the proximal convoluted tubual
what absorbs glucose and aa into the blood
epithelial cells in the lining of the pct
what makes the epithelial cells suited for their absorbtion
microvilli - provide large SA
mitochondria - provide lots of energy for active transport and co transport
what is the mitochondria in the epithelia cells used for
active and co - transport
describe the process of reabsorbtion
sodium ions actively transported into the blood lowering the sodium con in epithelial cells.
sodium ions diffuse down con-gradient into cells via facilitated diffusion with the use of a carrier protein.
travels from lumen of pct into epithelial cells surrounding it.
carrier protiens contransport molcules such as glucose and aa into epithelial cells
co-transported molecules diffuse dwn a conc gradient into the blood.
how do glucose molecules move into epethillial cells
via co-traqnsport with sodium ions through a carrier protien
how do sodium ions move into the epithellial cell
facillitated diffusion
how are the co-transported molecules transported into the blood stream
via diffusion down a conc gradient wich is alwas maintained as blood constantly moves away
how is ultra filtration resisted out of the glomerulas
cappillary epithelial cells
epithelila cells of renal capsual
what is esential for selective reabsorbtion in terms of establishing conditions
maintaining the gradient of sodium ions
what miantains the gradient of sodium ions
loop of henle
what are the two regions in the loop of henle
descending limb
ascending limb
what is the differance between the ascending and descending loop
descending lopp is permiable to water
ascending loop has thicker walls so is not
why is the ascending loop imperable to water
because it has thicker walls
what happens in the ascending loop of henely
sodium ions actively transported out into intertitial space
what does the active transport of na ions out of ascending loop mena
lowers water potential outside
due to the low water potential outside loop of henle what happens
water moves out of descending loop into the surrounding blood capillaries wich is hopw water enters the blood
where else does water go when it moves out os descending limb
interstitial space
what is the concentration at the bottom of the loop of henle
high conc of na+ ions becuase most water has moved out via desceding loop, this means that na+ ions can easily diffuse out into interstitial space
why is their a high conc of na ions at the bottom of loop of henle
because most water has moved out via descending loop
what does this high conc of sodium ions mean
sodium can easily diffuses out into interstitial space
what changes that makes na+ ions move out of ascending loop via activetransport
as their is a large amount of na+ ions at the bottom of the loop of henle they can easliy move out via diffusion but as more move out the conc of na+ ions left is lower so they have to move out via active transport
what does the movment of the na+ ions out of the ascending loop result in
a filtrate with a high water potential
why does it result in a filtrate with a high water potential
as water is unable to move out in the ascending loop due to it’s thick walls
after movement out of loop of henle where does filtrate go
collecting duct
what happens at the collecting duct
water moves out via osmosis into blood capillaries
what does the osmosis of water out of collecting duct mean
lowered water potential
what continues to allow osmosis in collecting duct even when their is a low water potential in collecting duct
water potential of filtrate is lower but so is water potential of interstilita space due to the constant movement of blood taking water away so water keeps moving out of collecting duct. this is an example of the counter current model
why is the water potential of interstial space still lower than that in collecting duct
due to constant movement of water away bu the blood capillaries
