7.10 - Respiratory System
Alveoli
Tiny, grape-like air sacs at the very end of the bronchioles in the lungs. This is where the crucial exchange of oxygen and carbon dioxide between the lungs and the blood happens.
Bronchi
The two main, large tubes that branch off from the trachea (windpipe), with one bronchus leading into each lung.
Bronchioles
Smaller airways that branch off from the bronchi, similar to how twigs branch off from a tree limb. They lead air to the alveoli.
Cellular Respiration
The metabolic process that happens inside your body's cells. It uses oxygen to break down glucose (sugar) to create energy (ATP), releasing carbon dioxide as a waste product.
Cilia
Tiny, hair-like projections that line the airways (like the trachea and bronchi). They move in a wave-like motion to sweep mucus, dust, and trapped debris up and out of the lungs, helping to keep them clean.
Epiglottis
A small, flexible flap of cartilage at the base of the tongue. When you swallow, it folds down to cover the opening of the larynx (voice box) to prevent food and drink from entering your trachea (windpipe).
Expiration
The act of breathing out. The diaphragm and rib muscles relax, causing the chest cavity to shrink, which pushes air (rich in carbon dioxide) out of the lungs.
External Respiration
The exchange of gases between the air in the lungs (alveoli) and the blood in the capillaries surrounding them. Oxygen moves from the alveoli into the blood, and carbon dioxide moves from the blood into the alveoli.
Inspiration
The act of breathing in. The diaphragm contracts and moves down, and the rib muscles contract, expanding the chest cavity. This pulls air (rich in oxygen) into the lungs.
Internal Respiration
The exchange of gases between the blood in the capillaries and the body's tissues/cells. Oxygen moves from the blood into the cells, and carbon dioxide moves from the cells into the blood.
Larynx
The "voice box." This is a short tube in the neck, located between the pharynx and the trachea, that contains the vocal cords, which vibrate to produce sound.
Lungs
The two main organs of the respiratory system, located in the chest. They are spongy, air-filled organs where gas exchange takes place.
Nasal Cavities
The large, air-filled spaces inside the nose. They are lined with mucus and cilia that warm, moisten, and filter the air you breathe in before it reaches the lungs.
Nasal Septum
The thin wall of cartilage and bone that divides the nasal cavity into its two separate left and right passages.
Nose
The primary external opening for the respiratory system, which allows air to enter and exit the body. It's also the organ for the sense of smell.
Pharynx
The "throat." This is the passageway behind the nasal and oral (mouth) cavities that connects them to both the larynx (for air) and the esophagus (for food).
Pleura
A thin, two-layered membrane. One layer covers the outside of the lungs, and the other lines the inside of the chest cavity. The space between them contains fluid that allows the lungs to slide smoothly as you breathe.
Respiration
The overall process of gas exchange in the body. It includes ventilation (breathing), external respiration (lungs-to-blood), and internal respiration (blood-to-cells), all to support cellular respiration.
Respiratory System
The complete set of organs and tissues responsible for breathing. This includes the nose, pharynx, larynx, trachea, bronchi, lungs, and the diaphragm muscle.
Sinuses
Air-filled cavities (spaces) within the bones of the skull that are connected to the nasal cavities. They help lighten the skull, produce mucus, and contribute to the quality of your voice.
Trachea
The "windpipe." This is the main, rigid tube (held open by rings of cartilage) that carries air from the larynx down toward the lungs, where it splits into the two bronchi.
Ventilation
The mechanical act of breathing—the process of moving air in and out of the lungs (inspiration and expiration).