Chapter 26 Renal function
Proteinuria is
an important sign of basement membrane discomfort
Atrial natriuretic peptide (ANP) and urodilatin
decrease sodium reabsorption
Hydrostatic pressure within the glomerular capillaries
is the main driving force for filtration
Excess potassium is excreted from the body by the renal system primarily via
secretion based on aldosterone level
The blood urea nitrogen (BUN) level is affected by
Protein intake Fluid intake Catabolism Renal function
Approximately two thirds of the water and electrolytes filtered by the kidney are reabsorbed by the
Proximal tubule
More than 5 WBC per high power field
Indicate urinary tract infection
Normal urine pH range
4-6.8
Normal specific gravity of urine
1.010-1.025
Serious renal impairment generally does not occur until......... of total nephrons have been damaged.
75% to 90%
Hormones that increase sodium reabsorption from the tubular fluid include
Aldosterone Angiotensin II
Vasa recta
Are capillaries that surround the loops of Henle and collecting ducts and absorb interstitial fluid
Factors that increase the glomerular filtration rate include
Fluid volume excess
Renin is released from the
Juxtaglomerular cells
Glucose reabsorption
Occurs in the proximal convoluted tubule with the assistance of sodium dependent protein co-transporter
The underlying mechanism which directly results in glycosuria is
exceeding the threshold for glucose reabsorption
The primary selectivity barrier for glomerular filtration is the
glomerular basement membrane - prevents plasma proteins, RBCs, WBCs, and platelets from passing through the glomerulus
The glucose transporter in the proximal tubule
may be saturated at high filtered glucose loads- glycosuria then results is not ATP dependent has a transport maximum does exist beyond which glycosuria occurs a sodium-dependent protein co-transporter is needed
Serum creatinine may be increased by
muscle breakdown
The primary function of the vasa recta is to
reabsorb interstitial water.
The glomerular filtration rate is most accurately reflected in the
serum creatinine level