Breathing And Gas Exchange

BREATHING AND GAS EXCHANGE!

BREATHING

For Cellular respiration to take place, your cells need a constant supply of oxygen for this to

happen aerobically. Cells need to have waste Carbon Dioxide removed.

INHALATION

• Volume of chest cavity increases
• Diaphragm muscles contract -> Diaphragm flattens
• External intercostal muscles contract -> Pulls ribcage up and out
• Lower pressure in chest cavity than outside body -> Air flows in 

EXHALATION

• Volume of chest cavity decreases
• Diaphragm muscles contract -> Diaphragm dome shaped
• Internal intercostal muscles contract -> Pulls ribcage down and in
• Higher pressure inside the chest cavity than outside body -> air pushed out

STRUCTURE OF HUMAN GAS EXCHANGE

• Nasal passages = Warm, clean, addmoisture to the air
• Epiglottis = Stops food getting into lungs when you swallow
• Oesophagus = Carries food to stomach
• Larynx = Voice box
• Trachea = Tube with incomplete rings of cartilage that carries air to lungs. Lined with cells making mucus and cillia which move…