nephrone

• • Functional unit of kidney. Situated across cortex and medulla
• • Each nephron is closely associated with blood vessels, enabling the exchange of substances via passive and active transport between the blood and the fluid that becomes urine. 
• • Filtration: removal of water and substances from the blood
• • Reabsorption– returns essential substances from the tubules back into the blood
• • Secretion: removal of unwanted and toxic substances from blood into tubules
• • The product of these processes is excretion of nitrogenous wastes via urine which consists largely of water with urea and ions, e.g. sodium, potassium, hydrogen.