Human respiratory system
Ncert shortnotes on human respiratory system Human respiratory system consists of a pair of nostrils, pharynx, larynx, bronchi and bronchioles that finally terminates into alveoli. Nasal chamber open into pharynx that leads to larynx . Larynx contains voice box (sound box) that help in sound production. The trachea, primary, secondary and tertiary bronchi and initial bronchioles are supported by incomplete cartilaginous rings to prevent collapsing in absence of air. Each bronchiole terminates into an irregular walled, vascularized bag like structure called alveoli . The branching network of bronchi, bronchioles and alveoli collectively form the lungs. Two lungs are covered with double layered pleura having pleural fluid between them to reduce the friction on lung surface. Conducting parts include nostrils, pharynx, larynx and trachea. Main functions include- Transport of atmospheric air to alveoli. Removing foreign particles from air, humidifying it and bringing it to body tem