PHSI 208 Lecture Notes - Lecture 1: Breathing, Pulmonary Pleurae, Thoracic Cavity
Document Summary
The respiratory system has four primary functions: exchange of gases between the atmosphere and blood, homeostatic regulation of body ph, protection from inhaled pathogens and irritating substances, vocalization. The respiratory and circulatory systems coordinate to move oxygen and co2 between the atmosphere and the cells. External respiration requires coordination between the respiratory and cardiovascular systems. It takes place in a four step process: the first exchange (exchange i) is atmosphere to lung. There are many structures involved in ventilation and gas exchange: conducting system or airways, alveoli, the bones and muscles of the thorax (chest cavity) create the force to move air during breathing. The lungs are composed of light spongy tissue whose volume is mostly occupied by air-filled space. The right lung is slightly larger than the left due to the cardiac notch. Each lung is surrounded by a double-walled pleural sac. The pleural sac has two functions: creates moist slippery surface, holds lungs tight to the thoracic wall.
