Tiny, grape-like air sacs at the end of the bronchioles in the lungs. They are the primary site of gas exchange, where oxygen enters the blood and carbon dioxide is removed.
Alveoli
A leaf-shaped flap of cartilage located behind the tongue, at the top of the larynx (voice box). Its main function is to seal off the trachea during swallowing, preventing food and liquid from entering the lungs
Epiglottis
The "voice box," a short passageway that connects the pharynx (throat) with the trachea. It contains the vocal cords, which vibrate to produce sound
Larynx
The "throat." A muscular tube that extends from the back of the nasal cavities down to the larynx and esophagus. It serves as a passageway for both air (to the trachea) and food (to the esophagus).
Pharynx
The "windpipe." A strong tube made of C-shaped cartilage rings that extends from the larynx to the bronchi. It serves as the main passageway for air to travel to and from the lungs.
Trachea
The two main, large tubes that branch off from the trachea and lead into the right and left lungs.
Bronchi
The act of breathing out. The diaphragm and intercostal muscles relax, decreasing the size of the chest cavity and forcing air out of the lungs.
Expiration (Exhalation)
The two main, sponge-like organs of the respiratory system, located in the chest cavity. Their primary function is to facilitate the exchange of oxygen and carbon dioxide with the blood.
Lungs
A thin, two-layered membrane. The parietal pleura lines the inside of the chest wall, and the visceral pleura covers the surface of the lungs. The fluid between these layers lubricates the lungs, allowing them to slide smoothly against the chest wall during breathing
Pleura
The mechanical process of moving air in and out of the lungs; also known as breathing (which includes inspiration and expiration).
Ventilation
The smallest branches of the bronchi that spread throughout the lungs, leading to the alveoli
Bronchioles
The exchange of gases (oxygen and carbon dioxide) between the alveoli in the lungs and the blood in the pulmonary capillaries.
External Respiration
The two hollow spaces inside the nose, located behind the nostrils and separated by the nasal septum. They are lined with a mucous membrane that warms, filters, and moistens inhaled air.
Nasal Cavities
The entire process of gas exchange between the body and the environment. It includes ventilation (breathing), external respiration (in the lungs), and internal/cellular respiration (in the cells).
Respiration
The metabolic process that occurs inside body cells. Cells use oxygen and nutrients (like glucose) to produce energy (ATP), water, and carbon dioxide.
Cellular Respiration
The act of breathing in. The diaphragm and intercostal muscles contract, increasing the size of the chest cavity and pulling air into the lungs
Inspiration (Inhalation)
The wall of bone and cartilage that divides the nasal cavity into two separate passages (right and left).
Nasal Septum
The network of organs and tissues responsible for breathing. It includes the nose, pharynx, larynx, trachea, bronchi, bronchioles, lungs, and alveoli.
Respiratory System
Tiny, hair-like structures that line the airways (like the trachea and bronchi). They move in a wave-like motion to sweep mucus, dust, and debris up and out of the lungs, helping to keep them clean.
Cilia
The exchange of gases (oxygen and carbon dioxide) between the blood in the capillaries and the body's tissue cells.
Internal respiration
The external organ on the face that serves as the primary entrance to the respiratory tract. It houses the nasal cavities and is responsible for inhaling, filtering, warming, and moistening air, as well as the sense of smell.
Nose
Air-filled cavities within the bones of the skull that are connected to the nasal cavities. They help to lighten the skull, produce mucus, and influence voice quality.
Sinuses