A minimal amount of pleural fluid present in the pleural cavity:
1. | provides a medium for the exchange of respiratory gases |
2. | reduces friction between the visceral and parietal pleurae |
3. | provides lubrication for movements of the diaphragm |
4. | permits the exchange of electrolytes during respiration |
The trachea divides into a right and a left primary bronchus at the level of:
1. 2nd thoracic vertebra | 2. 3rd thoracic vertebra |
3. 5th thoracic vertebra | 4. 12th thoracic vertebra |
The alveoli are lined with:
1. Simple cuboidal epithelium
2. Pseudo-stratified columnar ciliated epithelium
3. Transitional epithelium
4. Simple squamous epithelium
I: | P is an incomplete cartilaginous ring seen only in trachea and principal bronchus. |
II: | Q is the point where the trachea divides into a right and left primary bronchus and corresponds to the level of 5th thoracic vertebra. |
III: | R shows the double-layered pleura where the outer pleural membrane is in close contact with the thoracic lining. |
IV: | S is pleural cavity with minimal amount of pleural fluid which reduces friction on the lung surface. |
1. Only I, II and III | 2. Only I, III and IV |
3. Only II, III and IV | 4. I, II, III and IV |