Explain the process of breathing in man.
Ans.
Inspiration: When we breathe in, diaphragm contracts and lungs expands. When air is sucked in from the outside into the lungs, lungs get filled with air.
Gaseous Exchange: Hemoglobin in red blood cells binds with oxygen and delivers to all the cells and takes carbon dioxide from the cells. Carbon dioxide rich hemoglobin comes back to lungs where carbon dioxide is exchanged with oxygen on alveolar surface.
Expiration: When we breathe out, our lungs contract and push the carbon dioxide rich air (where the carbon dioxide from the cells has reached the alveoli and get exchanged for oxygen)