Question

In mammals, ventilation movements of lungs are governed by

• A. Muscular wall of lungs
• B. Intercostal muscles
• C. Diaphragm
• D. Diaphragm and intercostal muscles

Answer 1

The correct option is D Diaphragm and intercostal muscles

Diaphragm is a muscular partition between thorax and abdominal cavity. A muscular diaphragm is characteristic of mammals. Mammals are also provided with costal muscles, which can move the rib cage. There are two sets - external and internal intercostal muscles. The intercostals cause movements of rib cage. This along with movement of diaphragm increases or decreases volume of air tight thoracic cavity. Thus bringing about breathing movements.