7.10 Key Terms
alveoli
Tiny air sacs at the ends of the bronchioles where the exchange of oxygen and carbon dioxide between the air and the blood actually takes place.
epiglottis
A flap of tissue (elastic cartilage) that guards the entrance to the trachea (windpipe) and automatically closes when you swallow to prevent food and liquid from entering the lungs.
larynx
The voice box, which forms a passage between the pharynx and trachea and contains the vocal cords that vibrate to produce sound.
pharynx
The throat; a muscular tube that collects incoming air from the nose and mouth and passes it down to the trachea.
trachea
The windpipe; the large tube that connects the larynx to the bronchi, acting as a passage for air to the lungs.
bronchi
The large air tubes that branch off the trachea, with one tube leading into each lung. They further divide into smaller bronchi.
expiration
The act of breathing out, or exhaling, which releases air (including carbon dioxide) from the lungs.
lungs
The pair of cone-shaped, spongy organs located in the chest that are responsible for taking in oxygen and getting rid of carbon dioxide.
pleura
The two protective membranes that surround each lung lobe and separate the lungs from the chest wall.
ventilation
The process of moving air between the environment and the lungs. It is often used interchangeably with breathing, or external respiration.
bronchioles
The progressively smaller tubes within the lungs that branch from the bronchi. They end in the alveoli.
external respiration
The process of gas exchange between the body and the external environment, involving the movement of oxygen into the lungs and carbon dioxide out of the lungs.
nasal cavities
The hollow space within the nose, separated by the nasal septum, that warms, moisturizes, and filters air entering the body.
respiration
The overall process of breathing, which is the exchange of oxygen and carbon dioxide.
cellular respiration
The process in which cells break down glucose (sugar) to release energy, producing carbon dioxide and water as waste products.
inspiration
The act of breathing in, or inhaling, which pulls air (containing oxygen) into the lungs.
nasal septum
The structure that divides the nasal cavity into a left and right section.
respiratory system
The body system made up of the organs and structures (lungs, airways, etc.) that facilitate gas exchange and allow the body to breathe.
cilia
Tiny, hair-like structures that line the respiratory tract, filtering out dust, germs, and other particles from the air and sweeping mucus and debris toward the throat to be swallowed.
internal respiration
The process of gas exchange that occurs internally, where oxygen and carbon dioxide are exchanged between the blood and the body's cells (tissues).
nose
The main external opening for the respiratory system; a structure made of cartilage and bone that protects the anterior part of the nasal cavity.
sinuses
Hollow spaces (paranasal sinuses) located in the bones of the head that connect to the nasal cavity and help to regulate the temperature and humidity of inhaled air.