Respiratory System Quiz

The respiratory system is a biological system consisting of specific organs and structures used for ______ exchange

Gas exchange in the lungs occurs in millions of small air ______; in mammals and reptiles these are called alveoli, and in birds they are known as atria

These microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the ______

These air sacs communicate with the external environment via a system of ______, or hollow tubes, of which the largest is the trachea

The two main bronchi enter the lungs where they branch into progressively narrower secondary and tertiary ______