Question

Define the following terms: [5 MARKS]
(a) Ultrafiltration
(b) Micturition
(c) Renal pelvis
(d) Urea
(e) Osmoregulation

Answer 1

Each Part: 1 Mark

(a) Ultrafiltration- Blood flows through the glomerulus under great pressure. The reason being the efferent (outgoing) arteriole narrower than the (incoming) afferent arteriole. This high pressure causes the liquid part of the blood to filter out from the glomerulus into the renal tubule. This filtration under extra-ordinary force is called Ultrafiltration.

(b) Micturition- The urine is transported to the urinary bladder by peristaltic movements of the ureter. The bladder progressively fills with urine. Periodically, the urine is emptied to the exterior along the urethra by conscious action. The muscles of bladder wall contract. The passing out of urine is called micturition.

(c) Renal Pelvis- The pelvis is a hollow funnel-shaped expanded region of kidney which opens into the ureter. The collecting duct receives the contents of many kidney tubules and pours it as urine in the pelvis of the kidney.

(d) Urea- Urea is formed in the liver as a result of deamination of excess amino acids and is released into the blood. The kidneys extract urea from the blood and excrete it from the body as urine.

(e) Osmoregulation- To maintain the osmotic pressure of the blood at a constant level, the kidney while removing wastes (like urea) from blood also regulates its composition i.e. the percentage of water and salts. The process of controlling the water content and concentration of ions in the body is called osmoregulation.