Introduction of lungs airway and blood supply Flashcards
What are average volume of oxygen and CO2 exchanged ?
250ml oxygen consumed
200ml CO2 produced
What is breathing rate?
10-20 breaths per min at rest
40 -45 breaths max in adult exercise
What is trachea division, diameter, number and cross section area?
1, 15-22mm, 1, 2.5cm
What is Primary bronchi division, diameter, number and cross section area?
1, 10-15mm, 2, between 2.5cm and 100cm
What is alveoli division, diameter, number and cross section area?
24, 0.3mm, 3-6x10^8, >1x10^6
Where are Type 1 and 2 cells found and what do they do?
Make up alveoli.
Type 1 = gas exchange
Type 2 = synthesize surfactant
Alveolar macrophage ingest foreign material that reach alveoli
What is anatomical dead space?
Air between walls of upper airways because walls too thick to allow gases to cross so their function is just conduction of air to and from alveoli.
What does increase in energy demand cause?
- Rate and depth increase = speeds up O2 acquirement and CO2 disposal
- Heart rate and force of contraction = speeds up O2 delivery and waste removal
Define the steady state
Net volume of oxygen exchanged in the lungs per unit time is equal to the net volume exchanged in the tissues.
Define Boyle’s law
Pressure exerted by a gas is inversely proportional to its volume
Describe the visceral and parietal membrane
Visceral: coats the outer surface of the lungs
Parietal: coats inner surface of the ribs
What is the function of the pleural fluid?
Prevent ribs and lungs pulling apart due to elastic forces
Describe pathophysiology of asthma
Asthma – over-reactive constriction of bronchial smooth muscle.
Increases resistance, expiration phase most affected.
Describe the Transpulmonary pressure
difference between alveolar pressure and intra-pleural pressure. ALWAYS positive (in health) because Pip is always negative. PT = PA – Pip.
Say whether alveolar pressure in mmHg is neg or pos in inspiration and expiration
Negative in inspiration
Positive in expiration
