NURS 251 Pharm Exam 5

Main functions of the respiratory system - (1) deliver oxygen to the cells of body. (2) remove carbon dioxide from body. upper respiratory tract - outside chest cavity (nose, and nasopharynx; down to the larynx). lower respiratory tract - organs within chest (trachea, bronchial tree, and lungs). alveoli - microscopic sacs where oxygen diffuses across and exchanged for carbon dioxide when a person breathes in air the diffused oxygen is then taken to the rest of the body through the - circulatory system Several common diseases that affect airways and exchange of gas - asthma, COPD, emphysema, chronic bronchitis Asthma - general term for recurrent and reversible shortness of breath resulting from the narrowing of the bronchi and bronchioles. COPD - consists of both emphysema and chronic bronchitis. emphysema - a disease process involving inflammation of the alveoli. chronic bronchitis - chronic inflammation or irritation on the lower respiratory tract, specifically the bronchi. The primary drugs used in the treatment of both asthma and COPD - bronchodilators and a variety of anti-inflammatory and antiallergic agents. All three of these diseases have one primary similarity - they all involve obstruction of airflow through the airways. Chemical Mediators - are defined as a substance released from mast cells and white blood cells during inflammation and allergic reactions. As such, chemical mediators are responsible for most of the symptoms and complications associated with asthma and COPD. The only chemical mediator with a known involvement where drug therapy has been shown to help patient symptoms is - Leukotrienes Leukotrienes - are potent bronchoconstrictors with a long duration of action. They stimulate receptors responsible for bronchoconstriction, edema and other inflammatory actions. leukotriene inhibitors - a class of drugs that inhibit these actions and have an important role in treating asthma specifically. Asthma pathophysiology - -narrowing of the bronchioles can be caused by bronchospasm, inflammation, edema and the production of mucus. -This ultimately obstructs airflow meaning that the carbon dioxide cannot t get out and the oxygen cannot get in. Emphysema pathophysiology - -occurs when the air spaces enlarge as a result of the destruction of the alveolar walls. -The cause of this appears to be enzymes that are released in response to inflammation. -Hyperinflation is the result of the air spaces being enlarged. -This results in a reduction in gas exchange and the feeling of shortness of breath. chronic bronchitis pathophysiology - irritants cause mucus secretions to increase and thicken which can begin to interfere with gas exchange within lungs. Drug therapy for both asthma and COPD - Bronchodilation (historically) and anti-inflammatory (more recently popular) and are often used in combination Bronchodilation - include medications that improve airflow by relaxing smooth muscle cells in bronchials, leading to dilation and increased airflow. Anti-inflammatory - - Inhaled corticosteroids (ICS), Leukotriene Inhibitors - "controller" drugs because they reduce and control the inflammatory response. - When inflammatory response is under control, bronchodilator drugs can work more effectively. three types of bronchodilators - beta adrenergic agonists, anticholinergic, and theophylline. Beta adrenergic agonists mechanism of action - relax and dilate the airways by stimulating the beta2 adrenergic receptors within the lungs.