NEET BIOLOGY

Detailed explanation-1: -When the lungs inhale, the diaphragm contracts and pulls downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and fills the lungs.

Detailed explanation-2: -When the diaphragm and external intercostal muscles contract, the volume of the thorax increases. The contraction of the diaphragm increases the internal height of the thoracic cavity. The contraction of the external intercostal muscles causes expansion of the rib cage as it moves the ribs upward and outward.

Detailed explanation-3: -Lung volume expands because the diaphragm contracts and the intercostals muscles contract, thus expanding the thoracic cavity. This increase in the volume of the thoracic cavity lowers pressure compared to the atmosphere, so air rushes into the lungs, thus increasing its volume.

Detailed explanation-4: -Respiratory muscles As the diaphragm contracts, it increases the length and diameter of the chest cavity and thus expands the lungs. The intercostal muscles and neck muscles help move the rib cage and thus assist in breathing.

Detailed explanation-5: -During inspiration the diaphragm and the external intercostal muscles contract, causing an increase in the thoracic cavity volume. The contraction of the diaphragm accounts for approximately 75% of the air movement during normal breathing.