Question

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

Answer 1

(a) Ultrafiltration: The blood flows through the glomerulus under great pressure which is much greater than in the capillaries elsewhere. The reason for this greater pressure is that the efferent arteriole is narrower than the 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 extraordinary force is called ultrafiltration.
(b) Micturition: Urine is expelled from the urinary bladder through the urethra by relaxation of the sphincter muscles located at the opening of the urinary bladder into the urethra under impulse from the nervous system such a process is called micturition.
(c)Renal pelvis:The front end of the ureter is somewhat expanded into the kidney and is called the renal pelvis.
(d) Urea:Urea is the chief excretory product in terrestrial animals which is excreted in the urine.
(e) Osmoregulation:The kidney while removing wastes like urea from the blood also regulates its composition, i.e., the percentage of water and salts. This function is called osmoregulation – it implies the regulation of osmotic pressure of the blood.