Q. Arrange the given steps by which the pulmonary volume increases in the sequence of events occurring first I. Contraction of intercostal muscles II. Lifting up of the ribs III. Sternum causing an increase in the volume of the thoracic chamber in dorsoventral axis IV. Contraction of the diaphragm which increases the volume of the thoracic chamber in antero-posterior axis Choose the correct option
A) I $\rightarrow$ II $\rightarrow$ III $\rightarrow$ IV
B) IV $\rightarrow$ I $\rightarrow$ II $\rightarrow$ III
C) IV $\rightarrow$ I $\rightarrow$ III $\rightarrow$ II
D) I $\rightarrow$ III $\rightarrow$ IV $\rightarrow$ II
Explanation
Pulmonary volume increases by the following steps (i) Contraction of the diaphragm (ii) Contraction of intercostal muscle (iii) Lifting of the ribs (iv) Sternum causing an increase in the volume of thoracic chamber in dorso ventral axis [image:17_image19.png]
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.