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Explain human respiratory system? Class10 |
| Answer» Respiratory system in human beings: The respiratory system in human beings consists of the nose, pharynx, larynx, trachea, bronchi and lungs. Air is taken in through the nostrils. Nostrils further continue into the nasal cavity. There is a bony plate called the palate, which separates the oral cavity from the nasal cavity. Nasal cavity opens into the pharynx. The pharynx is a muscular chamber acting as a common passage for the windpipe or trachea and the food pipe or oesophagus. It is connected to the larynx through a slit-like opening called the glottis. The larynx connects the pharynx to the trachea. The trachea shows the presence of cartilaginous rings. The cartilaginous rings provide flexibility thus, facilitating continuous air flow. The inner wall of the trachea is lined by a mucous membrane consisting of ciliated columnar epithelium. The trachea divides into two branches or tubes called bronchi, one of which enters the right lung and the other enters the left lung. The bronchi have cartilaginous rings for distention. Each bronchus divides into fine secondary bronchi. These bronchi further divide into finer tertiary bronchi. In the lungs, each bronchus finally divides into finer and smaller branches called bronchioles. The bronchioles further divide to form smaller terminal bronchioles. The bronchioles divide repeatedly to form a cluster of tiny air chambers called air sacs or alveoli. Alveoli have thin and moist walls which enable gaseous diffusion with blood capillaries. The lungs are a pair of spongy and elastic respiratory organs protected by a bony rib cage. The base of the lungs rests on the diaphragm. Each lung is covered by two membranes. The inner membrane is called the inner or visceral pleura and the outer membrane is called the outer or parietal pleura. The diaphragm is a curved, musculo-fibrous sheath which separates the thoracic cavity from the abdominal cavity. The diaphragm plays a major role during respiration. | |