Mechanics of Pulmonary Ventilation (POCKET GUYTON)

The reason for the expansion of the lungs is the muscles, and as the chest cavity expands and contracts, the volume of the lungs decreases and increases. Whenever the length or thickness of the chest cavity increases or decreases, the volume of the lungs changes at the same time.

Mechanics of Pulmonary Ventilation

Normal breathing without movement is achieved by the diaphragm. The diaphragm contraction during tail pulls the lower surface of the lungs down. During exhalation, the relaxation of the diaphragm and the elasticity of the structures of the lungs, chest wall, and abdomen compress the lungs. • When you inhale strongly, the elasticity is weak and you cannot finish it quickly. The additional strength is mainly achieved through the contraction of the abdominal muscles which push the contents of the stomach against the diaphragm.

When you train and contract your chest, your lungs expand and contract. When the ribs are raised, the ribs almost protrude forward and the breastbone also moves forward and away from the spine, thickening the chest anteriorly and posteriorly.

• The muscle that raises the ribs of the inspiratory muscle. The contraction of the external intercostal muscles causes the ribs to move up and down in a "bucket handle" movement. Secondary muscles include noclaid mastoid muscles, anterior serrated muscles, and scalene muscles.

• The muscles that suppress the ribs are the exhaled muscles, including the internal intercostal muscles and the rectal stomach. Other muscle cells push the stomach towards the diaphragmatic upset.

The movement of air is outside the lungs and pressure is the cause of the movement

Pleural pressure as the pressure of the fluid in the chamber between the pleura and the pleural wall. The normal pressure of the pleura at the beginning of the tail is about 5 cm water column, which is the number of aspirations the lung must have to fracture volume. During the tail, the expansion of the thoracic cavity pulls heavily on the surface of the lungs, and the CRE exerts an even greater, even more negative pressure, averaging about 7.5 cm of water.

Alveolar pressure is the water pressure in the air sacs of the lungs. When the glottis is open and there is no air movement, the pressure in all parts of the respiratory tree is equal to atmospheric pressure, which is considered to be 0 cm water column.

When inhaling, the pressure in the alveoli drops to around 1 cm of water column, which Suffi Sien needs to blow around 0.5 liters of air into the lungs in 2 seconds. • As long as reinforcement is occurring, the opposite change is performed. Alb hydraulic pressure is stimulated for 2-3 seconds around 0.5 L lung water.

Changes in pulmonary compliance or lung volume in each change unit in pressure transfer. Transprinting is the difference between Larem Alveo and Pleution Print. The sum of normal compliance to two general lungs in an average adult is about 200 ml / cm water. Compliance depends on the following elastic strength:

Power • Elasticity from lung tissue is mainly determined by elastin fibers and collagen fibers. Force • The elasticity due to surface tension in the alveoli is about two-thirds of the total elastic force in normal lungs.

Surfactants, surface tension and lung collapse

Water molecules are interested in each other. The water surfaces covering the alveoli contract against each other to form an interesting water molecule. This effort for the Air Force comes out of the cells and tries to collapse the cells. The net effect is to produce an elastic contractile force of the whole lung, called surface tension of the elastic force. Surfactants reduce respiratory function (increased compliance) with a decrease in alveolar surface tension. Surfactants are secreted by type II alveolar epithelial cells. The main component is the phospholipid dipalmitoyl phosphatidylcholine. presence of a surfactant

Book Reference: Pocket Gayton (12th ed.)