STEP 1 (process) ; to each their own
arterioles branch off the renal artery and lead to each nephron where they form a knot of capillaries( glomerulus) sitting inside the cup shaped Bowman's capsule
STEP 2 (process) ; tight squeeze and fit
the capillaries get narrower as they get further into the glomerulus which increases the pressure on the blood moving through them
why is the blood in the glomerulus at a higher pressure than we would initially think
the blood is coming directly from the renal artery which is connected to the aorta
STEP 3 (process); the great escape
eventually high pressures cause the smaller molecules being carried in the blood to be forced out of the capillaries and into the Bowman's capsule where they form filtrate
number of layers separating the blood in the glomerular capillaries from the lumen of the Bowman's capsule
three
what are the three layers separating the blood in the glomerular capillaries from the lumen of the bowman's capsule
endothelium of the capillary
basement membrane
epithelium of the Bowman's capsule
describe the first separating layer (cell layer) of the glomerular capillary/Bowman's lumen boundary
each capillary endothelial cell is perforated by thousands of tiny membrane-lined circular holes
describe the second layer (membrane) of the glomerular capillary/Bowman's lumen boundary
made up of a network of collagen and glycoproteins
describe the third layer (cell layer) of the glomerular capillary/ Bowman's lumen boundary
epithelial cells have many tiny finger-like projections with gaps between them
what are the epithelial cells of the Bowman's capsule called
podocytes
STEP 4 (process) ; Granted entry
as the blood passes through the glomerular capillaries the holes in the capillary endothelial cells and the gaps between the podocytes allows substances dissolved in the blood plasma into the Bowman's capsule
STEP 5 (progress) ; some left behind
red and white blood cells and platelets remain in the blood as they are too large to pass through the holes in the capillary endothelial cells
STEP 6 (process) ;additional security
the basement membrane acts as a filter as it stops large protein molecules from the getting through into the filtrate
what is the function of the basement membrane
to act as a filter to prevent large protein molecules from passing through into the filtrate
STEP 1 (occurrence); osmotic difference
ultrafiltration occurs due to the differences in water potential between the plasma in the glomerular capillaries and the filtrate in the Bowman's capsule
movement of water at a water potential gradient
down the gradient form a higher water potential to a lower water potential
factors and effects of water potential
high pressure increases
presence of solutes decreases
how does pressure affect the water potential in the glomerulus and Bowman's capsule
due to the wider lumen of the afferent arteriole and narrower lumen of the efferent arteriole, blood pressure is relatively high in the glomerulus which raises the water potential of the glomerulus above that of the Bowman's
result of higher pressures in the glomerular capillaries
water moves down the water potential gradient from the blood plasma in the glomerulus into the Bowman's capsule
how solute concentration affects the water potential in the glomerulus and Bowman's capsule
with the basement membrane as a filter plasma protein molecules are too big to pass through and stay in the blood so the solute concentration of the blood plasma in the glomerular capillaries is still higher than that of the filtrate in the Bowman's capsule lowering the water potential of the blood plasma below that of the filtrate
result of higher solute concentrations in the blood plasma of the glomerulus
water moves down the water potential gradient from the Bowman's capsule into the blood plasma in the glomerulus
which effect of either the pressure gradient or solute gradient outweighs the other
pressure over solute
which of either the blood plasma or filtrate has a higher overall water potential
blood plasma
what is the overall movement of water at the water potential gradient of the glomerulus and Bowman's capsule
down the water potential gradient from the blood into the Bowman's capsule