Mechanics Of Ventilation & Lung Capacity Flashcards
Breathing is…
Involuntary and controlled by Medulla Oblongata that detects concentration of CO2
Key components of Ventilation
Intercostal muscles & ribs, diaphragm, lungs, pleural membranes
What happens to ribs/diaphragm during inhalation?
Ribs expand. Diaphragm contracts (pulled down), intercostal muscles contract (to expand ribs)
What happens to your ribs/diaphragm during exhalation?
Ribs compress (get smaller), diaphragm and intercostal muscles relax
Exhalation Boyle’s Law,
Volume down pressure up. Air pressure in lungs is higher than atmospheric pressure air forced out of lungs
Inhalation process
- Diaphragm contracts causing it to shorten and flatten
- External intercoastal muscles contract and pull ribs upwards and outwards
- Both actions increase volume of thoracic cavity resulting in pressure drop
- Atmospheric pressure higher-air ruses into lungs
Exhalation process
- Diaphragm relaxes and returns to dome shape
- External intercoastal muscles relax and ribs fall back to resting position
- Both actions decrease volume of thoracic cavity resulting in pressure increase
- Pressure in lungs higher-air rushes in
What controls breathing rate?
Nervous system and circulatory system working together (signals brain stem from lungs, intercostal muscles, and diaphragm) monitored by chemical receptors sensitive to change in blood pH due to CO2- biggest impact on our breathing rate
Total lung capacity?
Maximum volume of air that can be inhaled during a single breath
Tidal Volume?
Volume of air inhaled or exhaled during a normal involuntary breath
IRV (inspiratory reserve volume)?
Volume of air forcibly inhaled after normal inhalation
EVR (Expiratory Reserve Volume)?
Volume of air forcibly exhaled after normal exhalation
Residual Volume
Volume of air remaining at lungs after forced exhalation
Vital Capacity?
Maximum amount of air inhaled or exhaled
