What does the chest wall have to do with it all Typically about 500 mL of air

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