12.10b Lung anatomy and disease Flashcards
What properties should all respiratory surfaces have?
- Large surface area
- Permeable
- Thin walls
- Moist as gases diffuse quicker in solution
- Efficient transport system to maintain a concentration gradient
What is the rate of diffusion equation?
Rate of diffusion = surface area x difference in concentration / disunion distance
Trachea
- Tube like structure that carries air from the mouth too the lungs
- C shaped rings of cartilage to provide movement but prevent collapsing
Bronchi
- Trachea splits into two bronchi as it enters the lungs
- Air travels to each lung via the bronchi
Bronchioles
- Bronchi further divides into bronchioles
- Supply the alveoli with air
Explain the alveoli structure
- Small sacs at the end of the bronchioles
- Barrier between the air in the lungs and the blood
- Have a large SA
- ## Rich blood supply
How are the gas in the alveolar air spaces separated from the blood?
By the alveolar squamous epithelium and the endothelium wall of the capillary
What does squamous mean?
Thin squashed cell
What is ventilation?
The mechanism of breathing
Breathing definition
A result of the difference in pressure between the air in the lungs and the air outside the body
Describe inhalation
- External intercostal muscles contract pulling ribcage up and out
- Diaphragm contracts and pulls down
- Thoracic cavity volume increases
- Pressure in lungs lower than atmospheric pressure
- Air moves into lungs down a pressure gradient
Describe exhalation
- External intercostal muscles relax
- Diaphragm relaxes and moves up
- Thoracic cavity volume decreases
- Pressure in lungs greater than atmospheric pressure
- Air moves out of lungs down a pressure gradient
Pulmonary ventilation rate equation
Pulmonary ventilation rate = tidal volume x breathing rate
Tidal volume definition
Natural breathing rate
Inspiratory/expiratory reserve definition
Extra volume required for a deep breath
