Question

How does excretion occur in human beings? <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> [Textbook Question 7b pg no.178]

Answer 1

The phenomenon of removal of waste material from the body is called excretion. kidneys, lungs and skin are the main organs for excretion.

In human beings, Kidneys are the primary component of the excretory system. The kidneys are made up of its structural and functional units called nephrons.

• When blood reaches the kidneys, the nephrons filter the blood. The useful substances (glucose, amino acids and different ions like H+, K+ and HCO3- ions etc) are absorbed by blood vessels while the harmful and waste materials (like urea, uric acid etc) are dissolved in water and removed from the body in the form of urine.

• This urine, formed in the kidneys, passes through the ureter, urinary bladder, urethra and finally, comes out of the body