Anatomy and Physiology Answer Key

4 1 2 3 28 3 a low blood ph increases rate and

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Unformatted text preview: oreceptors) travel in the vagus nerve. Low blood pH also stimulates the chemosensitive area in the medulla directly. (c) Blood pH is a good indicator of high carbon dioxide levels (and therefore a need to increase respiratory rate to remove the CO2 and obtain more oxygen). Smoking and the Lungs (page 171) 1. Long-term smoking results in increased production of mucus (in an attempt to trap and rid the lungs of smoke particles). This lung tissue is irritated and a cough develops associated with removing the excess mucus. The smoke particles indirectly destroy the alveolar walls, leading to coalescing of the alveoli and a substantial loss of lung surface area. The toxins in the smoke and tar damage the DNA of cells and lead to cancerous cells and tumors. 2. (a) Tars: Cause chronic irritation of the respiratory system and are also carcinogenic (b) Nicotine: Addictive component of tobacco smoke (c) Carbon monoxide: Markedly reduces the oxygen carrying capacity of the blood by binding to haemoglobin and forming a stable carboxyhaemoglobin compound. CO has a very high affinity for Hb (higher than that of oxygen) and will preferentially occupy oxygen binding sites. It is released only slowly for the body. 3. (a) Emphysema: Increasing shortness of breath (which becomes increasingly more severe until it is present even at rest). Chest becomes barrel shaped (associated with air being trapped in the outer part of the lungs). Often accompanied by a chronic cough and wheeze (caused by the distension (damage and coalescing) of the alveoli). Note: Chronic bronchitis and emphysema are often together called chronic obstructive lung disease. (b) Chronic bronchitis: A condition in which sputum (phlegm) is coughed up on most days during at least three consecutive months in at least two consecutive years. The disease results in widespread narrowing and obstruction of the airways in the lungs and often occurs with or contributes to emphysema. (c) Lung cancer: Impaired lung function; coughing up blood, chest pain, breathlessness, and death. 4. The evide...
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