Question

Over the years, coal miners inhale large quantities of fine coal dust that irritates their alveolar surfaces and results in inflammation and then development of scar-tissue (a tough-fibrous tissue) within their alveolar walls and on alveolar surfaces. (a) Define compliance. (b) Would coal miners have increased or decreased lung compliance? (c) Explain what this would mean for respiratory muscle contractions to achieve a normal TV. (3 points, 110 words)

(a)

(b)

(c)

First define each of the following lung volumes. Then consider: For an otherwise normal patient who has generalized (overall) skeletal muscle weakness, would each of these lung volumes be normal, increased or decreased AND explain. Hint: at least 1 is normal. (5 points, 400 words)

Inspiratory Reserve Volume

Answer 1

(a)Compliance: a measure of the ease of expansion of the lungs and thorax, determined by pulmonary volume and elasticity. A high degree of compliance indicates a loss of elastic recoil of the lungs, as in old age or emphysema. Decreased compliance means that a greater change in pressure is needed for a given change in volume, as in atelectasis, edema, fibrosis, pneumonia, or absence of surfactant. Dyspnea on exertion is the main symptom of diminished lung compliance.

(b) Coal miners have decreased lung compliance because scar tissue reduces compliance.

(c)  The muscle contraction will cause the diameter of the bronchus to decrease, thereby increasing its resistance. This in turn causes bronchoconstriction.

(a) Inspiratory reserve volume- The additional volume you inspire above the tidal volume. Decreased

(b) Functional Residual Capacity- The sum of expiratory reserve volume and residual volume. Normal

(c) Expiratory Reserve Volume- The amount of air forcefully exhaled after the end of a normal expiration. Decreased

(d) Residual Volume-The volume of air in the respiratory system after exhalation. Normal

(e) Vital Capacity- The sum of the inspiratory reserve volume, expiratory reserve volume, and tidal volume. Decreased

(a) The intrapleural pressure will rapidly decrease during a hiccup.

(b) The alveolar pressure will rapidly decrease during a hiccup.

(c) These pressure changes are inversely related to lung volume. So decreases pressures mean high lung volume.