Nephron HT Flashcards
What are the 5 segments of the kidney?
Functions?
Renal corpuscle-filter
Proximal convoluted tubule-reabsorbing solutes
Loop of henle-concentrate urine
Distal convoluted tubule-reabsorbing water and solutes
Collecting duct-reabsorbing water + control acid base & ion balance
The glomerular tuft is supported by what?
Smooth muscle mesengial cells
What are the layers of the glomerular filtration barrier?
Fenestrated endothelium
Glomerular basement membrane(double thickness)
Podocyte foot process
Blood supply to the kidneys is….
20% CO (1L)
Glomerular filtrate had same conc as ….. except …..
Plasma
Albumin (membrane bound) 0
What is allowed to be filtered through?
Anything 10kDa or smaller
Glomerular basement membrane is negative as it produces…. To….
Heparin sulfate
Repels negative molecules (albumin)
The corpuscle contains…
Afferent and efferent arteriole
Bowman’s capsule
What cells are found in the glomerulus?
AA and EA
Endothelial cells
Mesengial cells
What are mesengial cells and their 3 functions?
Modified smooth muscles
Structural support
Contraction of muscles tightens glomerulus, reduces GFR
Involved in phagocytosis
What are the 3 parts of the equation for glomerular filtration?
Hydrostatic pressure out of capillary
Hydrostatic pressure out of bowman’s capsule
Oncotic pressure in capillary (albumins) (water move into capillary)
Why does the bowman’s capsule have no osmotic force?
Has no proteins
What is the only protein in urine?
Where is it produced?
Tamm horsfall protein (uromodulin)
Thick ascending limb
Equation for GFR?
GFR = Kf (Pgc - Pbs - pi gc)
What is the Kf?
125 ml/min
GFR is measured in clinic using?
Marker substance, creatinine
Why is creatinine used?
Not metabolized
Not secreted/absorbed
Freely filtered
How often is plasma filtered every 24 hours?
60x every 24 hours
3L plasma, 125ml/min
180L/24 hrs
What is renal clearance?
Measure of how much a substance is secreted/absorbed
What cells are involved in juxtaglomerular feedback?
Cells?
Function?
Granular cells (endothelium of AA) - detect low BP Macula densa (DCT) detects low NaCl Mesengial cells - structural support
What do granular cells release?
Renin
When there is low NaCl and BP/sympathetic activation, what is released?
Renin secretion from granular cells to act on RAAS
What 2 things increase GFR?
What happens to renal corpuscle blood flow?
Dilate AA
Constrict EA
Increased renal blood flow at renal corpuscle
What 2 things decrease GFR?
What happens to renal corpuscle blood flow
Constrict AA
Dilate EA
Decreased blood at renal corpuscle
