Respiratory Anatomy Diaphragm Inhalation (active process) –Diaphragm and intercostal muscles contract, increasing the size of the thoracic cavity. –Diaphragm moves slightly downward, ribs move upward and outward. Air flows into the lungs creating a negative pressure in the chest cavity.
Respiratory Anatomy Exhalation (passive process) Diaphragm and intercostal muscles relax decreasing the size of the thoracic cavity. –Diaphragm moves upward, ribs move downward and inward. Air flows out of the lungs creating a positive pressure inside the chest cavity.
Respiratory Physiology Oxygenation - blood and the cells become saturated with oxygen Hypoxia - inadequate oxygen being delivered to the cells Signs of Hypoxia –Increased or decreased heart rate –Altered mental status (early sign) –Agitation –Initial elevation of B.P. followed by a decrease –Cyanosis (often a late sign)
Alveolar/Capillary Exchange Oxygen-rich air enters the alveoli during each inspiration. Oxygen-poor blood in the capillaries passes into the alveoli. Oxygen enters the capillaries as carbon dioxide enters the alveoli.
Capillary/Cellular Exchange Cells give up carbon dioxide to the capillaries. Capillaries give up oxygen to the cells.
Functions of the Respiratory System: Overview Exchange O 2 –Air to blood –Blood to cells Exchange CO 2 –Cells to blood –Blood to air Regulate blood pH Vocalizations Protect alveoli