The Urinary System

Question 1

Describe the physiological process of filtration, re absorption and secretion with reference to the nephron

Answer 1

Filtration takes place through the semipermeable walls of the glomerular capillaries and glomerular capsule
Water and other small molecules readily pass through, although some are re absorbed later
The fluid filtered from the blood into the glomerular capsule is called filtrate.
Large molecules are too big to be filtered e.g. blood cells so they remain in the blood

Question 2

List the substances that pass in or out of the nephron during filtration, re absorption and secretion

Answer 2

Filtration: water, mineral salts, amino acids, Leto acids, glucose, some hormones, creatinine, urea, uric acid, some drugs, leukocytes, erythrocytes, platelets, plasma proteins
Re absorbed: water, electrolytes, and nutrients including glucose and amino acids
Secreted: urea, uric acid and creatinine.