Respiration is the act of breathing:
Inhaling (inspiration). Taking in oxygen
Exhaling (expiration). Giving off carbon dioxide
The respiratory system is made up of the organs involved in the interchanges of gases and consists of the:
Mouth (oral cavity)
Larynx (voice box)
The upper respiratory tract includes the following:
The lower respiratory tract includes the following:
Airways (bronchi and bronchioles)
Air sacs (alveoli)
The lungs take in oxygen, which the body's cells need to live and carry out their normal functions. The lungs also get rid of carbon dioxide, a waste product of the cells.
The lungs are a pair of cone-shaped organs made up of spongy, pinkish-gray tissue. They take up most of the space in the chest, or the thorax (the part of the body between the base of the neck and diaphragm).
The lungs are enveloped in a membrane called the pleura.
The lungs are separated from each other by the mediastinum, an area that contains the following:
Heart and its large vessels
The right lung has three sections, called lobes. The left lung has two lobes. When you breathe, the air:
Enters the body through the nose or the mouth.
Travels down the throat through the larynx (voice box) and trachea (windpipe).
Goes into the lungs through tubes called main-stem bronchi:
One main-stem bronchus leads to the right lung and one to the left lung
In the lungs, the main-stem bronchi divide into smaller bronchi
Then into even smaller tubes called bronchioles
Bronchioles end in tiny air sacs called alveoli