reflex action occurs when the following incident happen in everyday life of human. Write importance of these following reflex actions 1. When food particles enter into the trachea 2. when foreign particles enter inside the nasal cavity.
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Answer:
1.The pharynx, or throat, is shaped like a funnel. During respiration, it conducts air between the larynx and trachea (or “windpipe”) and the nasal and the oral cavities. The pharynx includes three regions: The nasopharynx is posterior to the nasal cavity and serves only as a passageway for air. The oropharynx lies posterior to the oral cavity and contains the palatine tonsils. Both air and ingested food pass through the oropharynx and through the laryngopharynx below. The laryngopharynx lies posterior to the epiglottis and connects to the larynx (superiorly) and the esophagus (inferiorly). As we breathe, the epiglottis stays up and air passes freely between the laryngopharynx and the larynx.
2.The nasal cavities are chambers of the internal nose. In front, the nostrils, or nares, create openings to the outside world. Air is inhaled through the nostrils and warmed as it moves further into the nasal cavities. Scroll-shaped bones, the nasal conchae, protrude and form spaces through which the air passes. The conchae swirl the air around to allow the air time to humidify, warm, and be cleaned before it enters the lungs. Epithelial cilia (commonly called “nose hair”) and a mucous membrane line the inside of the cavities. The cilia, along with mucus produced by seromucous and other glands in the membrane, trap unwanted particles. Finally the filtered, warmed air passes out of the back of the nasal cavities into the nasopharynx, the uppermost part of the pharynx.