Excretion

Excretion
Outline the need for excretion in all living organisms.
State that excretory products in plants include oxygen, and in animals they include carbon dioxide and nitrogenous compounds.
Discuss the relationship between the different nitrogenous waste products and habitat in mammals, birds and freshwater fish.
Surplus amino acids must be degraded to relatively harmless nitrogen-containing compounds. Freshwater fish can get rid of ammonia, although highly toxic (due to its basicity), because it can be diluted by the readily available water. Birds are unable to carry too much water so they excrete uric acid which is insoluble and expelled as a paste (most of the water is removed before excretion). Mammals excrete urea. Some desert mammals produce very concentrated urine (having a long loop of Henlé). See 12.2.6.
The Human Kidney
Draw the structure of the kidney.
Include the cortex, medulla, pelvis, ureter and renal blood vessels.
Draw the structure of a glomerulus and associated nephron.
Explain the process of ultrafiltration including blood pressure, fenestrated blood capillaries and basement membrane.
Define osmoregulation.
Osmoregulation -- the control of the water balance of the blood, tissue or cytoplasm of a living organism.
Explain the reabsorption of glucose, water and salts in the proximal convoluted tubule, including the roles of microvilli, osmosis and active transport.
Explain the roles of the loop of Henlé, medulla, collecting duct and ADH in maintaining the water balance of the blood.
Compare the composition of blood in the renal artery and renal vein, and compare the composition of glomerular filtrate and urine.
Outline the structure and action of kidney dialysis machines.