What does the chest wall have to do with it all?
Oxygen and Carbon Dioxide Exchange ▪ Surfactant : secreted by cells in alveoli, facilitates expansion – Decreases surface tension on alveolar wall which allows easier expansion and prevents collapse upon expiration – Allows diffusion of O2 and CO2 to take place ▪ Any edema (interstitial edema) or inflammation in the lungs (pneumonia) interfere with gases ability to diffuse – Alveoli fill with fluid, and gas can’t diffuse (exchange) – Exhaling causes increase in pH (alkaline) ▪ 97% of O2 carried by RBCs – Attaches to hemoglobin to form oxyhemoglobin ▪ 77% CO2 transported by plasma, 23% transported by HGB
Effects of aging ▪ Decrease in immune system – Susceptible to resp infections ▪ Decreased cough reflex – Risk for aspiration increases ▪ Osteoporosis -> kyphosis – Impairs lung expansion ▪ Loss of elastic recoil in lung – Increased work of breathing ▪ Muscle atrophy – Decreased respiratory strength ▪ Decreased response to hypoxia and hypercapnia – Body unable to compensate for lower O2
Causes of Respiratory Disorders ▪ Trauma, disease, nervous system disorders ▪ Bacteria and other organisms ▪ Tobacco smoke, allergens, poisonous gases, and other toxic substances cause irritation and inflammation ▪ Familial tendency – Asthma and allergies
Restrictive Diseases/ Decreased Lung Capacity ▪ Defined by disorders that decrease lung capacity ▪ Scoliosis and kyphosis – Decrease the SIZE of the chest cavity ▪ Arthritis increases stiffness of the chest wall ▪ Pneumothorax : collapsed lung – diminishes lung surface ▪ Neuromuscular disorders -- weaken strength of resp muscles – i.e. myasthenia gravis ▪ Disorders that increase stiffness and decrease lung volume – Pneumonia, atelectasis (collapsed lung), and fibrosis
Obstructive Pulmonary Diseases ▪ Characterized by problems moving air in and out of lungs ▪ Narrowed tracheobronchial tree ▪ Asthma, emphysema, and chronic bronchitis ▪ Tumor in the lung
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- Fall '19
- cough, Upper Respiratory, of Respiratory Disorders