Respiratory System

     Similar to all mammals, primates have a constant body temperature, an

efficient respiratory system featuring a separation between the nasal and

mouth cavities, an efficient four-chambered heart that prevents mixing of

oxygenated and deoxygenated blood, among other characteristics.  Like

humans and other land animals, Chimpanzees breathe out of nostrils in their

noses and with the help of lungs. A pair of lungs are found in the airtight

thoracic cavity that is bound by a convex muscular and elastic sheet called a


      When breathing normally through the nose, the air travels through the

nasal passages that are lined with ciliated mucous epithelium.  There are

sensory cells that detect odors. As the air continues through the pharynx or

the throat, it crosses the path of food. This is the reason why we can breathe

through our mouth. Then, air passes the epiglottis, enters the voice box, also

known as the larynx, and goes down the trachea or windpipe. Through each

lung there are bronchioles that run through them, then divides in a tree like

way to give smaller bronchioles and finally deposits the air in the microscopic

thin walled air sacs or alveoli. A group of alveoli appear like a group of grapes

and gives the lungs a sponge like structure. In each lung there are about 150

million alveoli. Altogether they cover a large surface area that is

approximately 70 square meters.

      The blood that flows to the lungs by the pulmonary artery has little oxygen

and a lot of carbon dioxide. On the other hand, the air in the alveoli has a high

concentration of oxygen and less carbon dioxide.  Thus a 2-way diffusion

takes place through the cells of the capillaries. Oxygen enters the blood and

CO2 leaves it. Since a lot of breathing surface of lungs is exposed to the

outward environment the exchange of gases is computed within few seconds.