Respiratory Physiology Diaphragm contracts - increase thoracic cavity vl - Pressure decreases - causes air to rush into lungs Diaphragm relaxes - decrease thoracic cavity vl - Pressure increases – forces air out of lungs

Inspiration

Expiration

Spirogram Spirometer

Pulmonary volumes Values determined by using a spirometer –Tidal volume – amount of air inhaled or exhaled with each breath under resting conditions –Inspiratory reserve volume – amount of air that can be inhaled during forced breathing in addition to resting tidal volume –Expiratory reserve volume – amount of air that can be exhaled during forced breathing in addition to tidal volume –Residual volume – Amount of air remaining in the lungs after a forced exhalation.

Mini Lab Lung Capacity Calculations

Pulmonary Gas Exchange Blood enters pulmonary capillary O 2 diffuses into blood CO 2 diffuses out of blood

Regulation of Breathing Your respiratory rate changes by activity The Medulla & Pons Regulate controls automatic breathing consists of interacting neurons that fire either during inspiration (I neurons) or expiration (E neurons)

Patterns of Breathing Apnea – temporary cessation of breathing (one or more skipped breaths) Dyspnea – labored, gasping breathing; shortness of breath Eupnea – Normal, relaxed, quiet breathing Hyperpnea – increased rate and depth of breathing in response to exercise, pain, or other conditions Hyperventilation – increased pulmonary ventilation in excess of metabolic demand Hypoventilation – reduced pulmonary ventilation Orthopnea – Dyspnea that occurs when a person is lying down Respiratory arrest – permanent cessation of breathing Tachypnea – accelerated respiration

Clinical Disorders and Diseases Hypoxia – low O 2. Oxygen toxicity – high 0 Chronic bronchitis – cilia are immobilized → mucus clogs the airways and breeds infection Emphysema – alveolar walls break down and the surface area of the lungs is reduced Asthma – allergens trigger the release of histamine and other inflammatory chemicals that cause intense bronchoconstriction. Lung cancer –most common cancer and most common cause of cancer deaths in U.S. males. Acute rhinitis – the common cold Laryngitis – inflammation of the vocal folds Pneumonia – lower respiratory infection of the alveoli that causes fluid build up in the lungs. Sleep apnea – Cessation of breathing for 10 seconds or longer during sleep Tuberculosis – pulmonary infection with Mycobacterium tuberculosis; reduces lung compliance Pleuritis - Inflammation of the pleura, producing more than the normal amount of fluid, causing a pleural effusion. The pain fibers of the lung are located in the pleura. When this tissue becomes inflamed, it results in a sharp pain in the chest that is worse with breathing in. Cystic fibrosis - caused by inheriting two defective CFTR genes, a transmembrane protein needed for the transport of Cl− ions out of the epithelial cells of the lung thus enabling water to follow by osmosis. Diminished CFTR function reduces the water content of the fluid in the lungs making it more viscous and difficult for the ciliated cells to move it up out of the lungs. The accumulation of mucus plugs the airways interfering with breathing and causing a persistent cough. Cystic fibrosis is the most common inherited disease in the U.S. white population.transmembrane proteinosmosis ciliated cells