Excretion is a process of removal of waste from the body. Excretion in unicellular organisms is performed by body wall or contractile vacuoles.Excretion in multi-cellular organisms is performed by flame cells, nephrons.Homeostasis is maintenance of internal environment of body.Urinary system helps in removal of liquid waste.Kidneys are major organs of excretion.Excretory system in humans is formed by kidneys, liver.Medulla is an inner part of kidney. Cortex is an outer part of kidney.Nephron is a unit of excretory system.Structure of Nephron includes Malpighian cup and renal tubule.Glomerulus is formed by afferent arteriole.Bowman’s Capsule is a funnel like proximal part of nephron.Henle’s Loop is hair pin turn part of renal tube.
Ureter is a tube extending from pelvis.Urinary bladder is a storage organ of urine. Urethra is a small duct of urinary bladder.Kidney-excretory pathway -blood carried by renal artery to nephron , to renal pyramid, to pelvis , to ureter, to urinary bladder, to urethra , to outside.Urine is pale yellowish liquid waste.Ultra filtration takes place in Malpighian cup.Selective reabsorption occurs in renal tubule.Tubular Secretion occurs in distal convoluted tubule.Artificial Kidney is a dialysis machine. Dialysis is a process in which patient’s blood is purified outside the body by a machine.Cork is a dead tissue derived from plant body.Vacuoles are cell organelles of plant cell.Gum and Resins are excretory substances of plant body.