24 June 2013

#84 Ventilation, role of intercostal muscles and diaphragm

There are 2 sets of muscles which help you to breath:
- intercostal: between the ribs

- diaphragm: a large sheet of muscle and elastic tissue, underneath the lungs and heart. 



Figure below shows the relationship between intercostal muscles, diaphragm and ribcage to achieve ventilation of the lungs.


Two set of intercostal muscles are attached to the ribes. They are antogonistic.

1. Breathing in (inhaling)
  • The external intercostal muscles contract, they move the ribcage upward and outward --->  volume of the thorax.
  • The diaphragm muscles contracts ---> diaphragm moves down 
  •  volume of the thorax
  • air pressure in the thoracic cavity
  •  air rush into the lungs through the mouth or nose.

2. Breathing out (exhaling) 
The opposite happens:
  • The internal intercostal muscles contract
  • The diaphragm muscles relax ---> diaphragm moves up 
  •   volume of the thorax
  •  air pressure in the thoracic cavity
  •  air rush out of the lungs.

Features
Inspiration
Expiration
Intercostal muscles
external
muscles contract
internal
muscles contract
Ribcage moving
upward
outward
downward
Diaphragm muscles
contract

relax
Diaphragm
move
move
Thorax volume
Air pressure in thorax cavity
lower than air
pressure outside
higher than air pressure outside
air rushes
into the lungs
out of the lungs




1 comment:

  1. shuh.....this is very interesting,very simple and understandable!!!!!!!! keep it up

    ReplyDelete