Question

How different parts of excretory system works

Answer 1

$\textbf {The biological process of removal of harmful nitrogenous waste from the body is called excretion.}$

HUMAN EXCRETORY SYSTEM CONSISTS OF:-
1. A pair of kidneys.
2.A pair of ureters
3.Urinary bladder.
4.Urethra.

PROCESS OF EXCRETION:-
1. ULTRAFILTRATION -- The blood passes through glomerulus which has a tuft of blood capillaries. Only the small molecules of substances present in blood like glucose, amino acids,salts ,urea,water ect. pass through glomerulus and collect as filtrate in bowmans capsule. The large molecules like proteins and blood cells can not pass hence remain in blood.

2. Selective Reabsorption-During Reabsorption substances considered necessary in filtrate are reabsorbed by renal tubule which then travel back into bloodstream. Max. Reabsorption take place in PCT because of the precense of microvilli.

3.Tubular secretion -- Passage of unwanted substances directly into renal tubules is called tubular secretion.

SO from above process only waste materials remain in tubule. The liquid remained behund in tubule is carriesd to ureter. From ureter,urine passes through urinary bladder and Ultimately passed through urethra