intro to resp physiology Flashcards
What is the anatomical dead space?
The volume of air that does not take place in gas exchange
What is the physiological dead space?
sum of the anatomical dead space plus the alveolar dead space
what is alveolar dead space?
- areas of dead tissue where gas exchange no longer occurs
Describe the characteristics of bronchioles
- they lack cartilage
- their smooth muscle layer is relatively thicker
- no glands in submucosa
- non ciliated clara cells present in epithelium
what are the 2 types of alveolar cells?
- Type I
- Type II
what is the function of type I alveolar cells?
- they facilitate gas exchange
- they can communicate ith type II cells
what is the function of type II alveolar cells?
- they produce and secrete pulmonary surfactant
- they can regenerate alveolar epithelium after injury
in what direction (in terms of pressure) does air flow?
- air moves in bulk flow from regions of high pressure to low pressure
what are changes in alveolar pressure** caused by**?
- changes in dimension of the lungs / chest wall
what muscles are mainly involved in inspiration?
- the **diaphragm **
- when diaphragm contracts, the abdominal contents are forced downwards & fowards
- rib margins are lifted and move outwards
- **external intercostal muscles **contract which causes ribs to be pulled upward and forward
what is an obstructive lung disease caused by?
- characterised by a** reduction in airflow **
- ie shortness of breath in exhaling air
- the air will remain in the lung after full expiration
what are examples of obstructive lung conditions?
- COPD
- asthma
- bronchitis
how are restrictive lung diseases defined?
- a reduction in lung volume
- ie difficulties taking in air into the lung as the lung is stiff
what are examples of restrictive lung conditions?
pulmonary fibrosis
