Breathing - Biology
Forced Expiration
- Internal intercostal muscles contract, diaphragm and external intercostal muscles relax.
- Ribs move further downwards and inwards.
- Volume in thorax becomes smaller
- Pressure is increased
Air is forced out against the pressure gradient
Gross Anatomy of the respiratory system
Trachea
Bronchi
Bronchioles
Alveoli
Inspiration
External Intercostal Muscles contract
Diaphragm contracts and flattens
Ribs move up and out
Volume increases so the pressure decreases below atmospheric pressure
Ribcage moves down and in
Why does ventilation rate increase when we excercise
Muscles contract - more energy
aerobic respiration needed
Oxygen Increases
Carbon Dioxide builds up so need to get rid
Lactic acid produced in anaerobic respiration