Section 2 i) Key Words

ADH: Anti-diuretic hormone causes the tubules of the nephron to become more permeable and thus reabsorb more water.

Bladder: The organ where urine is stored before being expelled from the body through the urethra.

Bowman's capsule: The capsule encasing the glomerulus, receives the glomerular filtrate through ultrafiltration.

Convoluted tubule: The two convoluted tubules (proximal being the closer one to the glomerulus, distal being the further one) are where water, glucose, and salts are reabsorbed into the blood.

Glomerular filtrate: The substance created by ultrfiltration. Made of glucose, urea, water and salts.

Glomerulus: A series of capillaries under high pressure that forces small molecules through the walls.

Homeostasis: Maintaining constant internal conditions, e.g. temperature, water content, etc.

Hypothalamus: The part of the brain that detects water content and stimulates the pituitary gland.

Loop of Henle: A loop of tubule within the nephron where salts and water are reabsorbed. Separates the two convoluted tubules.

Nephron: The filtration unit within the kidney that removes waste products and cleans the blood.

Osmoregulation: Regulation of water content. The skin sweats, the kidneys remove and reabsorb water, and the lungs exhale water vapour. These all regulate how much water is in our bodies.

Pituitary gland: The gland that releases ADH.

Selective reabsorption: The reabsorption of some chemicals but not others, e.g. all glucose is reabsorbed, but only a certain amount of water and salt is, and no urea.

Ultrafiltration: The process of filtering the blood to separate large particles such as cells from small molecules such as glucose. Produces glomerular filtrate.

Urea: Substance created by breaking down amino acids. Toxic to the body, and excreted in urine.

Ureter: The tube that transports urine from the kidneys to the bladder.

Urethra: The tube that excretes urine from the bladder.