CHAPTER 39: OXYGENATION
1. Anatomy of respiratory The pathway for transport and exchange of 02 and C02 Cooperation of respiratory and cardiovascular systems -> promote optimal oxygenation 2. Anatomy of respiratory system Begin at the nose and ends at terminal bronchioles Upper airway: nose, pharynx, larynx, and epiglottis Lower airway: trachea, right/left main stem bronchi, segmental bronchi, terminal bronchioles Mucous: lines airway, trap debris, and protect underlying tissue Cilia: trapped material up the airway Lungs: left ft3 lobes), right ft2 lobes), and composed of elastic tissue Alveoli: small air sacs at the end of bronchioles, made from single cell layer of squamous epithelium, covered in capillaries, site of gas exchanges, and surfactant reduces surface tension in alveoli prevent collapse Pleura: serous membrane; visceral pleura cover lungs, parietal pleura lines thoracic cavity ; these are continuous and form a sac ftsac is filled with pleural fluid -> lubricate and allows lungs move along the chest wall easily); pleural in the pleural space is always sub-atmospheric ftholds the lungs in the expanded position) Pulmonary ventilation: movement of air in and out of lungs ftinhalation and exhalation) Inverse relationship: pressure and volume
INHALATION
Active phase Diaphragm contracts and descends into thoracic cavity Intercostal muscles contract lifting the ribs Sternum pushes forward enlarging the chest >increase lung volume and decreases intrapulmonary pressure: allows for atmospheric air to move from area of greater pressure ftoutside body), to area of lesser pressure ftlungs) EXPIRATION Passive phase Diaphragm relaxes, ribs move down, sternum drops back Decrease lung volume and increase intrapulmonic pressure ftair move from area of greater pressure ftlungs) to area of lesser pressure ftoutside body) 3. Factors affect inhalation and exhalation 3.1.Compliance: ability of lungs to be inflated; depends upon elasticity Decrease elasticity decrease compliance ftaging, emphysema) 3.2. Airway resistance Impedes air movement into lungs Obstruction: foreign body, tumors, thick mucous, liquids Constriction: asthma 4. Respiratory 4.1.Gas exchange Occurs in alveoli Diffusion: movement of gas particles from area of higher pressure/ concentration to area of lower pressure/ concentration to area of lower pressure/ concentration
Affected by: * changes in surface area ftloss of tissue, tissue damage); * incomplete lung expansion ftatelectasis): thickening of alveolar capillary membrane ftPNA, edema); partial pressure ftaltitude); obstruction; immobility 5. Perfusion blood caries oxygen to tissues depends upon adequate blood supply and cardiovascular function 6. Regulation of the respiratory system
Medualla Chemo receptors in aortic arch Increase C02 and H+ -> decrease 02 to a Sensitive to changes in ABG's lesser degree Can activate the medulla Increase rate and depth of ventilation
7. Alterations in respiratory function 7.1.Hypoxia Inadequate amount of oxygen is available to cells -> caused by hypoventilation ftdecreased rate or depth of air movement into lungs) Signs of hypoxia Dyspnea: difficult breathing ft BP with small pulse pressure, 7 respiratory and pulse rate, pallor, cyanosis) A Anxiety A Restlessness A Confusion Drowsiness 7.2. Chronic hypoxia Detected in all body systems Altered thought process, headaches, chest pain, enlarged hearts, clubbing of fingers and toes, anorexia, constipation, decreased urinary outp