Respiratory System

Anatomy of the Respiratory System

What is respiration?

Respiration is the act of breathing:

inhaling (inspiration) - taking in oxygen
exhaling (expiration) - giving off carbon dioxide

What makes up the respiratory system?

The respiratory system is made up of the organs involved in breathing and consists of the:

nose
pharynx
larynx
trachea
bronchi
lungs

The upper respiratory tract includes the:

nose
nasal cavity
ethmoidal air cells
frontal sinuses
maxillary sinus
larynx
trachea

The lower respiratory tract includes the:

lungs
bronchi
alveoli

What do lungs do?

The lungs take in oxygen, which all cells throughout the body need to live and carry out their normal functions. The lungs also get rid of carbon dioxide, a waste product of the body's 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 inside 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
trachea (windpipe)
esophagus
thymus
lymph nodes

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
- and then into even smaller tubes called bronchioles
- bronchioles end in tiny air sacs called alveoli

This page was last updated on: January 18, 2008.

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