Question

During inspiration , the diaphragm
A)Becomes dome shaped
B)Flattens
C)Remains unchanged
D)Rotates sideways

Answer 1

Hint: The two lungs are the respiratory system's main organs. The breathing or respiration process is split into two distinct stages. Inspiration, or inhaling, is considered the first step.

Complete answer:
The main organs of the respiratory system are the two lungs. They are sitting inside a room called the thoracic cavity, to the left and right of the heart. The rib cage seals the cavity. Other portions of the respiratory system, such as the trachea, or windpipe, act as a sheet of muscle called the diaphragm, and bronchi conduct air to the lungs.

Although the pleural membranes and the pleural fluid enable the lungs to pass smoothly inside the cavity, inspiration or inhalation is called the first step. The diaphragm contracts and pulls downward as the lungs inhale. The muscles between the ribs are contracting and pushing upward at the same time.

This raises the size of the thoracic cavity and decreases the pressure inside. As a consequence, the second step is called expiration, or exhalation, and air rushes in and fills the lungs. The diaphragm relaxes as the lungs exhale, and the volume of the thoracic cavity decreases, while the pressure within it increases. The lungs contract and air are pushed out as a result.

Inspiration is the breathing process in which air gets into the lungs. Contraction of the inspiratory muscles initiates it:

Diaphragm-flattens, expanding the thoracic cavity's superior/inferior dimension.
The external intercostal muscles lift the ribs and sternum, expanding the thoracic cavity's anterior/posterior dimension.

Hence, the correct answer is option (B)

Note: An rise in lung volume results in a decrease in the pressure inside the lungs, as per Boyle's law. The pressure of the atmosphere outside the lungs is now greater than that of the environment inside the lungs, which ensures that air travels down the pressure gradient through the lungs.