Quiz 11: Drugs for the Respiratory System


At the cellular level, all cells of the human body require oxygen to survive. This oxygen is supplied from the atmosphere by the respiratory system. The respiratory system comprises of the airways and the lungs. The airways comprise of the nose, pharynx, larynx, trachea, bronchi and bronchioles, which lead into the lungs. The functions of each of these parts is as follows. Nose The nose provides the external opening through which atmospheric air enters the lungs. It has hair and mucus that keeps the nose moist. The hair help in making the air warm as it enters the air passages. Together, the hair and the mucus, trap external unwanted and harmful entities like dust and pollen and prevent them from entering further into the respiratory tract. When the lungs exhale air, the nose receives heat and moisture which again helps to keep it moist, even as the air passes out of the body. Pharynx When air is inhaled, it passes through the nasal passage and then through the pharynx enters further down the respiratory tract. Thus, the pharynx acts as a connector passage that directs the air from the nose into the respiratory tract. Larynx The larynx is functionally critical for respiration due to the epiglottis located at its superior border. The epiglottis closes the pharyngeal opening whenever food is swallowed and is about to pass through the larynx. This ensures that food does not enter the respiratory passage. Trachea The tracheal membrane has got cilia and secretes mucus. Its function is to trap the dust, pollens and other substances that might have been able to pass the hair and mucus in the nasal passage. Bronchi and bronchioles The bronchi and bronchioles both, have small cilia and mucus and trap foreign bodies entering the lungs. Their primary function though is to regulate the air entering the lungs. Whenever the body needs more supply of air, the bronchi and bronchioles enlarge in diameter and allow more air to pass through them into the lungs. Lungs The function of the lungs is to allow exchange of gases through its clustered structures called as alveoli. The alveoli of the lungs are one-cell thick to allow easy exchange of gases by simple diffusion. The blood brought by the pulmonary vein to the lungs is concentrated in carbon dioxide but poor in oxygen. Thus, oxygen readily enters the alveolar capillaries and carbon dioxide, which is less in the inhaled air, is drawn out of the capillaries.

The word root " pulmon " (Latin) means "the lungs." The adjective form pulmonary means related to the lungs. Lung (plural: lungs) is one of the paired organs located in the chest cavity and is protected by the rib cage. The lungs are the organs that are responsible for gaseous exchange across the body. Oxygen from the air is exchanged for carbon dioxide in the lungs. The lungs look like sponge, with numerous air-filled sac-like structures. Tiny capillaries line these sacs and aid in gas exchange. The word 'pulmonary' is used as a combining form. It is used to indicate anatomical position, for example, pulmonary capillaries (the blood capillaries of the lungs); and pathological conditions like pulmonary edema (accumulation of fluid in the lungs).

The number of times a person breathes in a minute is referred to as respiratory rate. It helps in concluding on several pathogenic conditions. For adults, it is considered normal to breathe between 12 to 25 times in a minute. Thus, a respiratory rate of 18 breathes per minute is considered normal respiration rate for an adult.

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