Question

describe the mechanism by which breathing occurs in human being including inspiration and expiration
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Answer 1

Answer:

Movements of your diaphragm and rib-cage move the chest cavity accordingly  during both expiration and inspiration.

Explanation:

Inspiration (breathing in)

Key points:

• The external intercostal muscles contract and the internal intercostal muscles relax, this raises the ribs upwards and outwards
• simultaneously the diaphragm contracts and flattens.
• Both actions increases the volume inside the thorax,causing the pressure inside the thorax to decrease.
• Since atmospheric pressure is greater, air moves into the lungs and they inflate.

Expiration (breathing out)

key points:

• The internal intercostal muscles contract and the external intercostal muscles relax
• This lowers the rib downwards and inwards
• The muscle in the diaphragm relaxes and bulges up due to pressure form organs below, for example the liver and stomach and contraction of the abdominal muscles.
• Both of these actions decrease the volume inside the thorax, causing the pressure inside the thorax to increase
• Elastic recoil of the alveoli helps to force air out of the lungs.

Cleaning air

The trachea, bronchi and bronchioles are lined with ciliated epithelial cells (cilia) and goblet cells.

Goblet cells produce mucus and dust particles and pathogens get trapped in this mucus.

The cilia beat to carry a stream of mucus removing particles and pathogens up to your nose and throat where u can swallow and the HCL in the stomach can take care of.