Gas Exchange miss estruch

• Breathing is the movement if air in and out of the lungs
• Respiration is a chemical reaction to release energy in the form of ATP
• Gas exchange is the diffusion of oxygen from the air into the alveoli, into the blood and of carbon dioxide from the blood into the air in the alveoli
• Ventilation includes the movement of the diaphragm and antagonistic interaction between the internal and external intercostal muscles
• When internal intercostal muscles contract, it leads to exhalation
• When external intercostal muscles contract, it leads to inhalation
• When inhalation occurs:

  -External muscles contract

  -Internal muscles relax

  -Diaphragm contracts

  -Air pressure in the lungs increases as air moves in

  -Lung volume increases

  -Air moves into lungs from a high to low pressure down a pressure gradient
• When exhalation occurs:

  -External muslces relax

  -Internal muscles contract

  -Diaphragm relaxes

  -Air pressure drops as air moves out

  -Lung volume decreases

  -Air moves out of lungs from a high to low pressure, down a pressure gradient