Basics
Human respiration is a process by which oxygen is received into the body and carbon dioxide is expelled. Oxygen is a vital component of human survival and is needed for several types of cellular respiration, while is poisonous to humans.
Muscles
The skeletal muscles of the thoracic cavity are used to in the process of respiration by contracting and forcing air in and out of the lungs. The two muscles primarily involved are the external intercostal muscles and the diaphragm, which is the sheet of muscle separating the thoracic and abdominal cavities. These muscles will contract when breathing out and expand while breathing in in order to allow air flow in and out of the lungs.
Air Flow
Upon entering through either the oral or nasal cavities, the oxygen from the ambient air will travel through the pharynx, trachea, left and right bronchi, secondary and tertiary bronchi, bronchioles, and finally arive at the alveoli. The alveoli is the site of the gas exchange of oxygen for carbon dioxide. The oxygen will move to the blood stream in order to be used in cellular respiration, while the carbon dioxide will then travel out in expiration. Some oxygen is still expelled with the carbon dioxide, however.
Tags: carbon dioxide, cellular respiration, , respiration while, respiration while carbon, while carbon