Question

Short / long answer type questions.
Write an essay on the respiratory system of a human being.

Answer 1

• In human beings, many organs take part in the process of respiration. These organs are called organs of the respiratory system. The main organs of the human respiratory system are nose, nasal passage, Trachea (windpipe), Bronchi, Lungs, and Diaphragm.
• The human respiratory system begins from the nose. The air then goes into the nasal passage. The nasal passage is lined is lined with fine hair and mucus. When air passes through the nasal passage, the dust particles and other impurities present in it are trapped by nasal hair and mucus so that clean air goes into the lungs.
• The part of throat between the mouth and windpipe is called pharynx. From the nasal passage, air enters into pharynx and then goes into the windpipe. Trachea does not collapse even when there is no air in it because it is supported by rings of soft bones called cartilage. The trachea runs down the neck and divides into two smaller tubes called bronchi at its lower end. The bronchi are connected to the two lungs.
• The lungs lie in the chest cavity or thoracic cavity which is separated from the abdominal cavity by a muscular partition called diaphragm. Each bronchus divides in the lungs to form a large number of still smaller tubes called ‘bronchioles’.
• The pouch-like air sacs at the ends of the smallest bronchioles are called alveoli. The walls of alveoli are very thin and they are surrounded by very thin blood capillaries. It is in the alveoli that gaseous exchange takes place.