HSC 215 Lecture Notes - Lecture 13: Elastin, Intrapleural Pressure, Hemoglobin
Document Summary
Respiratory system: general function is to obtain o2 for use by the body"s cells and to eliminate the co2 the body cells produce. Ventilation-the movement of air in and out of the lungs occurs as a result of pressure differences induced by changes in lung volumes. Primary determinant of resistance to airflow is the radius of the conducting airway. Ans controls contraction of smooth muscle in walls of bronchioles: symp= dilation, para= regulatory, asthma= contract. Air (like blood) flows from a high to low pressure. Pressures that influence ventilation: atmospheric pressure= 760 mmhg, intra-alveolar pressure (intrapulmonary pressure, intrapleural pressure (intrathoracic pressure) Changes in intrathoracic pressure allow changes in intra-alveolar pressure. If pressure within the thoracic cavity (and therefore alveoli) is less than atmospheric pressure, air enters the lungs. If the opposite is true, air exits the lungs. Boyle"s law- states that at any constant temperature, the pressure exerted by a gas varies inversely with the volume of a gas.
