Our Respiratory system
The respiratory system is composed of lungs and the respiratory tract consisting of the nose,naso-pharynx, the larynx, the trachea or the wind pipe, the bronchi and bronchioles. The bronchioles finally break into small sacs called alveoli which are surrounded by pulmonary capillaries. Gaseous exchange between the inspired air in the alveoli and the impure blood in the capillaries occurs at this level.
The lungs are covered by a sac called pleura. The inside of the sac is smooth and filled with a thin layer of fluid to allow the expansion of the lungs without friction. When thorax expands, the lungs expand and air is drawn into the alveolus which is known as inspiration. with collapsing of the thorax to the original size, the air thrown out, called expiration. the normal respiratory rate is 16-20 per minute in adult. It is more rapid in children being 40 per minute in a newborn baby & 30-32 per minute at the age of 5. The rate of respiratory rate to pulse rate is 1:4