Question

Which of the following events occur during inhalation in human beings :
1:The inter - coastal muscles pull the ribs inwardly.
2.The volume of thoracic cavity increases.
3.High pressure area is created inside the thoracic cavity .
4.Diaphragm becomes dome- shaped.

Which one is correct?
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Answer 1

Answer:

2

Explanation:

During inspiration the intercoastal muscles pull the ribs outward

The diaphragm flattens downward

So that the volume of thoracic cavity increases

Since volume and pressure are inversely proportional( basic physics)

Increased vol creates a low pressure

This pressure is lower than the atmospheric pressure

Hence air flows from outside into the lungs

Hope this helps

Answer 2

Answer:

the volume of thoracic cavity is increases