What initiates inspiration?

What initiates inspiration?
  1. The contraction of diaphragm
  2. The relaxation of diaphragm
  3. The contraction of internal intercostal muscles
  4. The relaxation of external intercostal muscles

Solution

Inspiration is initiated by the contraction of the diaphragm, which increases the volume of the thoracic chamber in the antero-posterior axis.

Asked in: NCERT

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