Question

Explain the process of respiration in human beings

Answer 1

The muscles of respiration contract thereby expanding the chest cavity.
This causes a negative pressure within the pleural cavity (where the lungs are housed) which forces the lungs to expand.
The expansion of the lungs reduces the air pressure in the lungs.
This draws air from the environment which is at a higher pressure. Air will flow from an area of high pressure to low pressure.
Air is taken in through the nose and the air is ‘filtered’ and heated in the nasal cavity.
It then passes down the throat and enters the trachea where it rushes into the bronchi.
The bronchi divides the air flow between the two lungs.
The air then passes into smaller air tubes known as bronchioles and empty into the lungs.
The air enters the tiny air sacs within the lungs, called alveoli, where oxygen crosses into the blood and carbon dioxide empties into the lung.
The respiratory muscles relax and the chest cavity contracts.
The elastic lungs recoil and pushes air out through the air passages where it is emptied into the environment.