AP BIOLOGY

Detailed explanation-1: -The diaphragm, located below the lungs, is the major muscle of respiration . It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily. Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges.

Detailed explanation-2: -The diaphragm is a thin dome-shaped muscle which separates the thoracic cavity (lungs and heart) from the abdominal cavity (intestines, stomach, liver, etc.). It is involved in respiration, drawing downward in the chest on inhalation, and pushing upward in exhalation.

Detailed explanation-3: -The diaphragm helps in the inspiration and expiration of air in and out of the lungs. At the time of inspiration, the diaphragm contracts, increasing the pulmonary volume, thereby reducing the intrapulmonary pressure to less than the atmospheric pressure, and air moves into the lungs.

Detailed explanation-4: -The diaphragm is an upward curved, c-shaped structure of muscle and fibrous tissue that separates the thoracic cavity from the abdomen. The superior surface of the dome forms the floor of the thoracic cavity, and the inferior surface the roof of the abdominal cavity.

Detailed explanation-5: -The diaphragm muscle is of the skeletal or striated type and is the major muscle of ventilation. Accessory muscles of ventilation include the scalene, the sternocleidomastoid, the pectoralis major, the trapezius, and the external intercostals.