Anatomy and Physiology Answer Key

B chronic bronchitis a condition in which sputum

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Unformatted text preview: nce linking cigarette smoking to increased incidence of respiratory and cardiovascular diseases and cancer is clear and convincing. The incidence of these diseases in smokers is much higher than in non-smokers even when other factors such as age and familial tendency are considered. For example, deaths from lung cancer in the UK are five times higher in smokers than in non-smokers. These differences are large enough to be statistically significant. Importantly, the evidence linking smoking to the incidence of specific diseases comes from many different sources and is not conflicting. Review of Lung Function (page 168) 1. Anatomy and Physiology 2. (a) (b) (c) (d) (e) (f) (g) Nasal cavity Oral cavity Trachea Lung Terminal bronchiole Alveoli Diaphragm (i) Medullary respiratory center (ii) Vagus nerve (iii) Intercostal nerve (iv) Chemoreceptors (v) Stretch receptors (vi) Phrenic nerve A = Inspiratory reserve volume B = Inspiratory capacity C = Tidal volume D = Expiratory reserve volume E = Residual volume vol: vol: vol: vol: vol: 3.3 3.8 0.5 1.0 1.2 L L L L L Respiratory Diseases (page 169) 1. Obstructive lung diseases are those in which the air cannot reach the gas exchange region of the lung, as occurs as a result of airway constriction (asthma), excess mucus (bronchitis), or reduced lung elasticity (emphysema). Restrictive lung diseases result from scarring of the gas exchange surface (fibrosis) which results in stiffening and lack of lung expansion. Such diseases result from inhalation of dusts (e.g. coal dust). 2. (a) In a chronic obstructive pulmonary disease, the FEV1 is reduced disproportionately more than the FVC resulting in an FEV1/FVC ratio less than 70%. (b) Although the FEV1/FVC ratio is reduced in asthmatics, there will be an improvement in the ratio towards the normal range (80%+) after treatment. (c) In a restrictive lung disease, both FEV1 and the FVC are compromised equally, so even though measures of lung function indicate impairment the FEV1/FVC ratio remains high. 3. Restrictive lung diseases, such as fibrosis, impair lung function because the gas exchange surface bec...
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