Question

give reasons 1)When urine is discharged , in beginning it is acidic in nature later it becomes alkaline 2)diameter of afferent arteriole is bigger than efferent arteriolepls answer fast

Answer 1

Formation and composition of urine

The urine leaving the kidney differs considerably in composition from the plasma entering it (Table 1). The study of renal function must account for these differences; e.g., the absence of protein and glucose from the urine, a change in the pH of urine as compared with that of plasma, and the high levels of ammonia and creatinine in the urine, while sodium and calcium remain at similar low levels in both urine and plasma.

Relative composition of plasma and urine in normal menplasma
g/100 mlurine
g/100 mlconcentration
in urinewater90–9395—protein7–8.5——urea0.032×60uric acid0.0020.03×15glucose0.1——creatinine0.0010.1×100sodium0.320.6×2potassium0.020.15×7calcium0.010.015×1.5magnesium0.00250.01×4chloride0.370.6×2phosphate0.0030.12×40sulfate0.0030.18×60ammonia0.00010.05×500

A large volume of ultrafiltrate (i.e., a liquid from which the blood cells and the blood proteins have been filtered out) is produced by the glomerulus into the capsule. As this liquid traverses the proximal convoluted tubule, most of its water and salts are reabsorbed, some of the solutes completely and others partially; i.e., there is a separation of substances that must be retained from those due for rejection. Subsequently the loop of Henle, distal convoluted tubule, and collecting ducts are mainly concerned with the concentration of urine to provide fine control of water and electrolyte balance