Lecture 30 - Tubular Reabsorption and Secretion

Diuresis

Increased production and excretion of urine by the kidneys.

Renal clearance

Volume of plasma completely cleared of a substance by the kidneys per unit time, typically measured in mL/min. It reflects kidney function and the efficiency of waste elimination.

Micturition

Process of urination, where the bladder expels urine through the urethra.

Describe the properties of urine

• Color: Typically pale yellow to amber due to urochrome pigment.

• Clarity: Usually clear but may become cloudy due to infections or substances.

• Odor: Slightly aromatic; strong odor may indicate dehydration or certain foods.

• pH: Ranges from 4.5 to 8, with an average of about 6.

• Specific Gravity: Measures urine concentration, typically 1.005–1.030.

• Composition: Mainly water (95%) with urea, creatinine, electrolytes, and waste products.

How is it calculated?

C = UV/P (u = urine concentration, v= urine production (ml/min), p= concentration in plasma)

GFR

Volume of filtrate formed per minute by both kidneys. kf= volume of filtrate per minute/mmhg.

males: 12.5mmhg

females: 10.5mmhg