The mechanism of breathing

HideShow resource information
  • Created by: Eema003
  • Created on: 16-05-16 10:07

Inspiration

  • External intercostal muscles contract, whilst the internal intercostal muscles relax
  • Ribs are pulled upwards and outwards, increasing the volume of the thorax
  • Diaphragm muscles contract, causing it to flatten, further increases volume of the thorax.
  • Increased volume of the thorax causes reduction of pressure in lungs
  • Atmospheric pressure is now greater than pulmonary pressure and so air rushes into the lungs

THINK OF A DIFFUSION GRADIENT

1 of 2

Expiration

  • Internal intercostal muslces contract, whilst the external intercostal muslces relax
  • Ribs move downwards and inwards, decreasing he volume of the thorax
  • The diaphragm muscle relax, further decreasing the volume of the thorax
  • Decreased volume of the thorax increases the pressure in the lungs
  • The pulmonary pressure is now greater than atmospheric pressure and so air is forcced out of the lungs.

THINK OF DIFFUSION GRADIENT

2 of 2

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Human, animal and plant physiology resources »