Nephrology

Kidney function
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Terms in this set (21)
Kidney function
Excretion of nitrogenous waste products and xenobiotics
Regulation of water, electrolyte, mineral and acid-
base balance
Production or activation of hormones (calcitriol — active vitamin D3; erythropoietin)
Kidney overview
Image: Kidney overview
Nephron overview
Image: Nephron overview
The blood supply to the nephron is unique because:
Two capillary beds are present in series with the efferent arteriole draining one and supplying the second
Determinants of glomerular filtration rate
a. Tubular hydrostatic pressure
b. Glomerular hydrostatic pressure
c. Ultrafiltration co-efficient of the glomerular capillaries
Autoregulation of glomerular filtration rate occurs to maintain a stable filtered load for the nephrons. If the filtered load is high how does the distal tubule respond and how does this reduce glomerular filtration rate?
Adenosine is secreted local to the afferent arteriole by the macula densa and causes afferent arteriolar constriction, lowering downstream glomerular capillary hydrostatic pressure which is one of the major determinants of GFR.
How can a proximal epithelial cell be identified as one
The brush border is microvilli which increase the surface area for absorption - since proximal tubular cells absorb 70% of the filtered load this is an important adaptation not seen in other renal tubular cells
What are the characteristics of the facilitated transport processes in the proximal convoluted tubule of the nephron?
a. These protein carriers move substances against a concentration gradient
b. The energy required comes from sodium moving down its electrochemical gradient into the cell
c. ATP is hydrolysed by the carrier complex and generates the energy for the transport process
The renal threshold for glucose is above the normal plasma glucose concentration so that glucose does not normally appear in the urine.
True
Normal plasma glucose concentration
The plasma glucose concentration is normally maintained at 3.5 to 5.5 mmol/l whereas the renal threshold for glucose is usually 10 to 12 mmol/l.