18) Give reasons for the following
(a) Lungs always contain residual volume
(b) Rate of breathing in aquatic animals is faster than terrestrial animals
(c) Nostrils are lined with mucus.
Answers
Answer:
a) The residual volume (RV) is the amount of air that is left after expiratory reserve volume is exhaled. The lungs are never completely empty; there is always some air left in the lungs after a maximal exhalation.
b)The breathing rate of aquatic animals is faster than that of terrestrial animals because the amount of dissolved oxygen in the water in much less than the amount on land, so they have to breathe more in order to get more oxygen
c)Rhinorrhea can be a symptom of other diseases, such as the common cold or influenza. During these infections, the nasal mucous membranes produce excess mucus, filling the nasal cavities. ... Chronic sinusitis occurs when one or more nasal polyps appear. This can be caused by a deviated septum as well as a viral infection.