exam3review

exam3review - (Respiratory System, Acid-Base Balance) 1....

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2402 Exam #3 Review (Respiratory System, Acid-Base Balance) 1. What is the mucus escalator of the respiratory system? What happens to this system of defense due to long-term smoking? The mucus escalator involves the production of mucus to capture microorganisms and debris and cilia to remove these potentially dangerous materials from the respiratory system. The cilia sweep the mucus upward toward the mouth where it is swallowed. The stomach’s acids and digestive enzymes destroy the potential pathogens. Long-term smoking causes excessive mucus production, immobilizes cilia, and destroys the delicate alveoli, leading to reduced oxygen-carbon dioxide exchange and opens the respiratory tract up to infection. 2. What is the purpose of the nasal conchae found in the nasal cavity? The nasal conchae are pieces of bone that protrude into the nasal cavity. They are covered with a mucous membrane. As air enters the nose, it is forced through grooves in the conchae and thus comes into close contact with the respiratory mucosa. Heat is transferred from the highly vascularized mucosa to the air, warming it. In addition, this heat causes the release of water from the mucosa, humidifying the air. 3. How is Boyle’s Law related to inspiration and expiration? Boyle’s Law explains how changes in the size of the thoracic cavity must occur so that inspiration and expiration can occur. Changing the size of the thoracic cavity alters the air pressure inside the cavity. Boyle’s Law says that gas pressure is inversely proportional to the volume of the container that the gas is in. To breathe in, the air pressure inside the thoracic must be less than atmospheric pressure (the total air pressure outside the body.) In order to reduce the air pressure inside the thoracic cavity, it must be expanded in volume (size). This is why inspiration is accomplished by the contraction of the diaphragm (which lengths the thoracic cavity) and by contraction of the external intercostals (which expand the thoracic cavity front to back). The thoracic cavity enlarges, reducing the air pressure inside it. Air then enters the lungs because air always moves from an area of higher pressure (outside the body) to an area of lower pressure (inside the thoracic cavity.) In expiration, air is moved out of the lungs because the situation has been reversed: air pressure inside the thoracic cavity is
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higher than atmospheric pressure because the thoracic cavity’s volume decreases as the diaphragm and external intercostals relax. 4. Why are the bronchi divided into three groups? Discuss the differences between the three divisions of bronchi. The divisions are based upon the areas of lung tissue they deliver air to.
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