NEETZoologyBreathing and Exchange of Gases
What is the purpose of the pleural fluid in the lungs?
Options
- ATo maintain the shape of the lungs
- BTo reduce friction on the lung surface
- CTo protect the lungs from external factors
- DTo provide structural support for the lungs
Correct answer
B. To reduce friction on the lung surface
Step-by-step solution
During swallowing glottis can be covered by a thin elastic cartilaginous flap called epiglottis to prevent the entry of food into the larynx. Trachea is a straight tube extending up to the mid-thoracic cavity, which divides at the level of 5th thoracic vertebra into a right and left primary bronchi. Each bronchi undergoes repeated divisions to form the secondary and tertiary bronchi and bronchioles ending up in very thin terminal bronchioles. The tracheae, primary, secondary and tertiary bronchi, and initial bronch