Term | Definition |
respiratory system | the group of organs that provides living things with oxygen from outside the body and disposes of waste products such as carbon dioxide |
respiration | all of the processes involved in bringing oxygen into the body, making it available to each cell, and eliminating carbon dioxide as waste |
inspiration | the action of drawing oxygen-rich air into the lungs |
expiration | the action of releasing waste air from the lungs |
gas exchange | the transfer of oxygen from the inhaled air into the blood, and of carbon dioxide from the blood into the lungs; it is the primary function of the lungs |
ventilation | the process of drawing or pumping, and oxygen-containing medium over a respiratory surface |
diffusion gradient | describes the relationship in which a dissolved substance moves from a region of high concentration to a region of low concentration |
diaphragm | a sheet of muscle that separates the thoracic cavity from the abdominal cavity |
Spirograph | a graph representing the amount (volume) and speed (rate of flow) of air that is inhaled and exhaled, as measuring by a spirometer |
tidal volume | the volume of air inhaled and exhaled during normal breathing |
inspiratory reserve volume | the volume of air that can be taken into the lungs beyond the regular tidal inhalation |
expiratory reserve volume | the volume of air that can be expelled from the lungs beyond the regular tidal exhalation |
vital capacity | the volume of air that can be exhaled from the lungs during a single breath |
residual volume | the volume of air that remains in the lungs after a complete exhalation |
pharynx | the passageway just behind the mouth that connects the mouth and nasal cavity to the larynx and esophagus |
trachea | the tube that carries air from the nasal passages or mouth to the bronchi and then to the lungs; also known as the windpipe |
glottis | the opening of the trachea through which air enter the larynx |
larynx | the structure between the glottis and the trachea that contains the vocal cords |
bronchus | the passageway that branches from the trachea to the lungs |
bronchiole | the passageway that branches from each bronchus inside the lung into increasingly smaller, thin-walled tubes |
alveolus | a tiny sac, with a wall that is one cell thick, found at the end of a bronchiole; respiratory gases are exchanged in this sac |
hemoglobin | an iron-containing protein found in red blood cells, which binds to and transports oxygen from the lungs to the rest of the body |