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 characteristic.
D - Lower end of lungs - diaphragm pulls it down during inspiration.
A - trachea - long tube supported by complete cartilaginous rings for conducting inspired air.
B - pleural membrane - surround ribs on both sides to provide cushion against rubbing.
C - Alveoli - thin walled vascular bag like structures for exchange of gases.
Alveoli -
Alveoli are the primary sites of exchange of gases.
- wherein
Exchanged in these sites by simple diffusion mainly based on pressure/concentration gradient.
Option 1)
D - Lower end of lungs - diaphragm pulls it down during inspiration.
Option is incorrect
Option 2)
A - trachea - long tube supported by complete cartilaginous rings for conducting inspired air.
Option is incorrect
Option 3)
B - pleural membrane - surround ribs on both sides to provide cushion against rubbing.
Option is incorrect
Option 4)
C - Alveoli - thin walled vascular bag like structures for exchange of gases.
Option is correct