Four Events That Occur In The Respiratory System

Air enters the nose by passing through the external nares or nostrils. The mucosa lining the nasal cavity, called the respiratory mucosa, warms the air as it flows pa

Respiratory physiology

The major function of the respiratory system is to supply the body with oxygen and to dispose of carbon dioxide. To do this, at least four distinct events, collectively called respiration, must occur:

1. Pulmonary ventilation

Air must move into and out of the lungs so that the gases in the air sacs (alveoli) of the lungs are continuously changed and refreshed.

This is commonly called breathing.

2. External respiration

Gas exchange (oxygen loading and carbon dioxide unloading) between the pulmonary
The air is ingested into the body and travels to the lungs, filling them up and causing them to expand. When the lungs expand, the diaphragm contracts and goes down, building pressure in the chest. This is what causes the rise and fall of the chest while a person is inhaling and exhaling air. The oxygen passes through the lungs, then enters the arteries in the body's circulatory system. Red blood cells carry the oxygen throughout the body. As the oxygen travels through the body, it becomes a form of heat and energy on which the body's tissue feeds. This enables the body to perform various functions, such as sending oxygen to the brain, and pumping blood to the heart. The energy and heat burn into fuel, turning into carbon dioxide that is carried back to the lungs through the
The lungs then eject the carbon dioxide, causing the exhalation process. As the lungs deflate, the carbon dioxide passes from the body through the nose and mouth. This entire process, inhaling and exhaling, is repeated, all occurring within a matter of seconds. In this brief span, the entire body is given the oxygen, fuel and energy it needs in order to function. (show video or pictures bibee. ü)

B. Nonrespiratory air movements

Nonrespiratory air movements are voluntary or reflex activities that move air into or out of the lungs. These include coughing, sneezing, laughing, crying, hiccupping, and yawning.

C. Respiratory volumes and capacities

Air volumes exchanges during air breathing are:

• tidal volume - amount of air inhaled or exhaled with a normal breath

• inspiratory reserve volume – amount of air that can be taken in forcibly over the tidal volume

• expiratory reserve volume – amount of air that can be forcibly exhaled after a tidal expiration

• vital capacity –total amount of exchangeable air or the respiratory