class 7 science textbook NCERT question what is breathing - Science - Respiration in Organisms

Question

class 7 science textbook NCERT question what is breathing

Pritam Sen · Accepted Answer

Dear student,

Breathing consist of inhalation and exhalation Inhalation means
taking air in, to get oxygen and exhalation means expelling air out
to release carbon dioxide A breathe means one inhalation and one
exhalation It involves the movement of ribcage and diaphragm
Diaphragm is made up of muscles which form the floor of chest
cavity, where lungs are situated
Steps of
breathing mechanism in humans:
i)
Inhalation: During inhalation rib
cage moves up and out and, diaphragm contracts and move down This
leads to increase in space of chest cavity and decrease in pressure
of lungs Then air goes into lung to fill the space with air
ii) Exhalation: This is
the reverse of inhalation Rib cage moves down and inwards, whereas
diaphragm relaxes and moves up This reduces the size of chest
cavity and increase in pressure, so air is pushed out of the
lungs

Regards