How does the respiratory syste essays

How does the respiratory syste essays How does the respiratory system achieve the movement of air in to and out of the lungs? Discuss the physical factors involved in quiet breathing. The respiratory system in humans consists of the lungs, series of tubes leading to the lungs and the chest structures responsible for moving air into and out of lungs. The lungs are found in a closed compartment bounded by the neck muscles and the diaphragm called the thorax. The thoracic wall contains large amounts of elastic connective tissue, which assists in the stretching of the lungs. Each lung is completely surrounded by a closed sac called the pleural sac. In between the 2 plural sacs of each lung there is an extremely thin layer of intrapleural fluid. Changes in the hydrostatic pressure of this fluid, the intrapleural pressure, cause the lung and thoracic wall move in and out during normal breathing. The exchange of air between the atmosphere and the alveoli is called ventilation. During ventilation air moves into and out of the lungs because the alveoli pressure decreases and becomes greater than atmospheric pressure. These pressure changes are caused by changes in dimensions of the lungs. Boyles law states that at a constant temperature an increase in the volume of a container decreases the pressure of a gas whereas a decrease in container volume increases the pressure. This law can be applied to the lungs. As the lungs change in volume this causes a change in alveoli pressure, which drives air into and out of the lungs. The volume of the lung depends on 2 factors: - 1. Transpulmonary pressure the difference in pressure between the inside of the lung (alveoli pressure- Palv) and the outside of the lungs (intrapleural fluid pressure- Pip) Transpulmonary pressure = (Palv) - (Pip) 2. Compliance- the ability of lung tissues to stretch. change in pressure There are no muscles attached to lung surf ...