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presure of capsular hydrostatic pressure is (HPc)
18 mmhg
pressure of blood colloid osmotic pressure is (OP)
32 mmHg
What determines how much is filtered?
Pressure
HP - (OP+HPc) = NFP
60 - (32+18) = 10 mm HG
pressure of glomerular hydrostatic pressure is (HP)
60 mm HG
What pressures oppose glomerular hydrostatic pressure?
Blood colloid osmotic pressure (OPg) and Capsular hydrostatic pressure (HPg)
What are the three cell types in the glomerulus aka FILTRATION MEMBRANE?
Endothelial cells, podocytes, and mesangial cells.
net filtration pressure
Filtration only occurs if the pressure that is promoting filtration is greater than the sum of its opposing pressures. The difference in these pressures is the NFP.
How does glucose get reabsorbed
It follows the NA gradient using an NA/glucose co transporter to leave the renal tubular and enter proximal convoluted tubule. It then enters capillaries by diffusion 100% of glucose is reabsorbed
What does the glomerular space (BOWMAN'S SPACE) hold and empty into?
It holds plasma ultrafiltrate and empties into renal tubules.
What gets filtered by filtration membrane?
It is a reasonably non selective barrier, almost anything gets through it except for LARGE PROTEINS.
What is glomerular pressure?
It is the pressure of blood in the glomerulus capillaries that "pushes" water and some solutes out of the glomerulus.
If you want to get rid of something from the body
LEAVE IT IN RENAL TUBULES
What happens if the filtration amount is equal to excretion
Nothing
Capsular hydrostatic pressure
Pressure in the glomerular capsule due to filtrate that is already present. It opposes glomerular hydrostatic pressure by IMPEDING THE MOVEMENT OF ADDITIONAL FLUID INTO FILTRATE
What happens if filtration amount is less than excretion?
Secretion. The body must secrete fluids back into the renal tubules so that it gets excreted in the urine.
What happens when filtration amount is greater than excretion?
Stuff must be recovered (reabsorbed) meaning most of the filtrate has to be reabsorbed back into the body
Where is the only place where blood flows from arteriole to capillary to arteriole
THE GLOMERULUS
What is tubular reabsorption
The movement of substances form the tubular fluid back into the blood via various types of transport
How do you change glomerular hydrostatic pressure?
by vasodilation or vasoconstriction of of either efferent or afferent arteriole.
endothelial cells of glomerulus
cells of the capillaries and is fenestrated. It is the innermost layer of the lumen which allows plasma and dissolved substances to be filtered. It restricts the passage of LARGE structures
Mesangial cells
cells positioned in and between glomerular capillary loops and have phagocytic can contractile properties
So the three layers of the filtration membrane aka glomerulus
endothelium (innermost) basal laminae (porous middle layer) visceral layer (outermost layer made up of podocytes)
Podocytes
forms the VISCERAL LAYER of the glomerulus. These are wrapped around glomerular capillaries. It restricts the size of molecules from entering the urinary space by forming pedicils and filtration slits.
If you want to keep something in the body
move it out of the tubules by REABSORPTION
Blood colloid osmotic pressure
the osmotic pressure exerted by the blood due to the dissolved solutes it contains. It opposes glomerular hydrostatic pressure by DRAWING FLUIDS BACK INTO GLOMERULUS
How does sodium get reabsorbed?
via active transport using Na/K ATPase pump to push sodium against their concentration gradients. NA moves from proximal convoluted tubule into blood 65% is reabsorbed
Ion transport for reabsorption
via diffusion from high concentration to low concentration to maintain and equilibrium