The diaphragm contracts, causing the lungs to expand. This creates a 'pressure difference' and air fills the lungs. When the diaphragm relaxes, it 'squeezes'[ the lungs, forcing the unabsorbed air (and waste gasses) back out again.
Pulmonary ventilation or breathing has two phases. Inspiration or inhalation moves air into the lungs and expiration or exhalation moves air out of the lungs. The lungs are enclosed within the thoracic cavity. Thus changes in the shape and size of the thoracic cavity result in changes in the air pressure within that cavity and in the lungs. This difference in air pressure causes the movement of air into the lungs. Air moves from an area where pressure is high to an area where pressure is low. Respiratory muscles are responsible for the changes in the shape of the thoracic cavity that cause the air movements involved in breathing.The abdominal diaphragm is (or should be) the major muscle driving respiration.Source(s):Structure and function of the body
Pulmonary ventilation or breathing has two phases. Inspiration or inhalation moves air into the lungs and expiration or exhalation moves air out of the lungs. The lungs are enclosed within the thoracic cavity. Thus changes in the shape and size of the thoracic cavity result in changes in the air pressure within that cavity and in the lungs. This difference in air pressure causes the movement of air into the lungs. Air moves from an area where pressure is high to an area where pressure is low. Respiratory muscles are responsible for the changes in the shape of the thoracic cavity that cause the air movements involved in breathing.The abdominal diaphragm is (or should be) the major muscle driving respiration.Source(s):Structure and function of the body
The main difference between the muscles involved in inspiration and expiration is that inspiration involves the diaphragm and external intercostal muscles, which contract to expand the chest cavity and draw air into the lungs. In contrast, expiration primarily involves the relaxation of these muscles, along with the internal intercostal muscles and abdominal muscles, which contract to compress the chest cavity and push air out of the lungs.
During inspiration, the diaphragm and intercostal muscles contract, expanding the chest cavity and allowing air to rush into the lungs. During expiration, the diaphragm and intercostal muscles relax, causing the chest cavity to decrease in size and air to be pushed out of the lungs.
During expiration, the diaphragm and intercostal muscles relax, causing the thoracic cavity to decrease in volume. This decrease in volume increases the pressure within the thorax, which pushes air out of the lungs. This process facilitates expiration by creating a pressure gradient that allows air to flow out of the lungs.
Expired means past use or dead. Inspired (inspire) means to be enlivened or filled with exalting emotion.
During quiet breathing, the intrapleural pressure decreases during inspiration as the diaphragm contracts and the thoracic cavity expands, leading to a decrease in pressure inside the lungs. During expiration, intrapleural pressure increases as the diaphragm relaxes and the thoracic cavity decreases in volume, causing an increase in pressure inside the lungs.
inspiration is an active process that takes place by creation of negative intrathoracic pressure, in normal states where breathing is vesicular, even at a low negative pressure air keep on flowing into alveoli but in bronchial breathing as alveoli are either filled with secretions as in consolidation or a cavity is already filled with air and other contents, no movement of air takes place at the end inspiration despite of negative intrathoracic pressure thereby causing a pause between inspiration and expiration- now pay me thousand dollar!
The diaphragm contracts and moves downward during inhalation, which increases the volume of the chest cavity. This decrease in pressure in the chest cavity creates a pressure difference that allows air to flow into the lungs.
This occurs within the respiratory system. During inpiration, the intercostal muscles contract, the diaphragm descends, and the rib cage rises. The thoracic cavity volume increases, stretching the lungs, and the intrapulmonary volume increases. This causes the intrapulmonary pressure to drop. Air flows into the lungs until the intrapulmonary pressure equals the atmospheric pressure. During expiration the intercostal muscles relax, the diaphragm rises, and the rib cage descends. The thoracic cavity volume decreases, causing the the lungs to recoil, and the intrapulmonary volume decreases. This causes the intrapulmonary pressure to rise, and the air flows out of the lungs until the intrapulmonary pressure equals the atmospheric pressure.
Normal expiration is brought on by the relaxation of the diaphragm and external intercostal muscles, causing the thoracic cavity to decrease in volume, which increases the pressure in the lungs. This increased pressure pushes air out of the lungs.
Intrapleural pressure becomes positive during forced expiration or coughing when the muscles contract forcefully to increase the pressure within the thoracic cavity. This positive intrapleural pressure helps to push air out of the lungs.