021 Mechanisms of Pulmonary Ventilation Flashcards
What accessory muscles are used in maximal ventilation?
Scalene muscles, sternocleidomastoid muscles, pectoral muscles, lattisimus dorsi
What muscles are used during forced expiration?
Abdominal muscles and a bit of internal intercostal muscles.
What is the conducting zone?
Conducting zone is area where air is filtered, humidified, and warmed. It takes place up to the entrance of the alveoli.
Where does resistance to air come from in the ventilation system
50% in the upper airways (larynx, pharynx, etc). In the lower airway, it mainly comes from resistance in the middle bronchus where there is mucus secretion and contraction.
What drugs are used as bronchodilators and what do they target?
Beta-2 agonists such as salbutamol to cause bronchodilation. M3 muscarinic receptor antagonists such as ipratropium or tritropium that block action of bronchoconstriction.
How would you measure lung function?
You can measure lung function by the peak expiratory flow (highest flow rate during forced expiration) or by the ratio between Peak expiratory volume in 1 second over forced vital capacity (PEV1/FVC).
Usually what is the tidal volume?
Tidal volume is usually 500ml, although we only absorb 350 into alveoli ml.
Discuss the intrapulmonary pressure in relation to intrapleural pressure (transpulmonary pressure), during rest, expiration, and inspiration.
During rest, intrapulmonary pressure always exceeds intrapleural pressure (usually by 4mmhG) so that lungs can push and stick to the thoracic wall. During inspiration, there will be negative intrapleural pressure compared to intrapulmonary pressure. During expiration, there will be positive intrapleural pressure compared to intrapulmonary pressure.
What does ipatropium and tritoprium do?
M3 muscarinic receptor antagonist that block action of broncho constriction
What does salbutamol do?
B2 agonist that causes bronchodilation
What is dead space?
Other 150ml of tidal volume is anatomically dead space. The air in alveoli that do not get exchanged is also classified as physiological dead space.
Which part of the brain controls rate and rhythm of breathing?
Pre-botzinger complex in the medulla oblangata
