Question

Write down the passage way of air along respiratory tract

Answer 1

lungs are situated in thoracic cavity .each lung receives a bronchus from the trachea . Each bronchus divides into many smaller and smaller tubes known as bronchioles . Each bronchiole terminate into balloon like structure called alveoli or alveolar sac. These increases the surface area for exchange of gases. The alveoli have very thin walls which are surrounded by blood capillaries. The exchange of gases occurr between the alveolar walls and walls of capillary