Breathing and Exchange of Gases Question 7
7. The figure shows a diagrammatic view of human respiratory system with labels A, B, C and D. Select the option which gives correct identification and main function and/or characteristics.
(a) B-pleural membrane-surrounds ribs on both sides to provides cushion against rubbing.
(b) C-Alveoli-thin walled vascular bag like structures for exchange of gases.
(c) D-Lower end of lungs-diaphragm pulls it down during inspiration
(d) A-trachea-long tube supported by complete cartilaginous rings for conducting inspired air.
Show Answer
Answer : b
Hints & Solution
(b) Alveoli are very thin, irregular walled bag like structures for gaseous exchange. Tracheae bronchi and bronchioles are supported by incomplete cartilaginous rings. Double layered pleural membrane surrounds the lungs with pleural fluid between them. It reduces friction on the lung surface.
