Ch. 7.10 Key Terms
tiny, thin-walled, air-filled sacs located at the ends of the bronchioles in the lungs. They are the primary site of gas exchange (external respiration) where oxygen diffuses into the blood and carbon dioxide diffuses out of the blood.
Alveoli
a flap of elastic cartilage located at the base of the tongue. It acts as a "lid" that closes over the opening of the larynx (voice box) during swallowing, preventing food or liquids from entering the trachea and lungs.
Epiglottis
a short passageway connecting the pharynx to the trachea. It is made of cartilage and houses the vocal cords, which produce sounds when air passes over them. It is regulated by the epiglottis.
Larynx
throat, is a muscular funnel-shaped tube that serves as a common passageway for both air (from the nasal cavities) and food/liquid (from the mouth). It connects the nasal/oral cavities to the larynx and esophagus.
Pharynx
windpipe, is a tube reinforced with C-shaped rings of cartilage that extends from the larynx down into the chest. It serves as the main passage for air to travel to the lungs, where it divides into the two bronchi.
Trachea
the two main air passages that branch off the trachea (windpipe) and lead into the right and left lungs. They are supported by cartilage and continue to divide into smaller passages called bronchioles.
Bronchi
the process of moving air out of the lungs. It is primarily a passive process resulting from the relaxation of the diaphragm and external intercostal muscles, causing the thoracic cavity to decrease in volume and forcing air out due to the recoil of the lungs.
Expiration
the primary organs of the respiratory system, located in the thoracic cavity. They contain the bronchi, bronchioles, and millions of alveoli, and their main function is to facilitate the exchange of gases (oxygen and carbon dioxide) between the air and the blood.
Lungs
two layers of serous membrane that surround and protect the lungs. The parietal pleura lines the thoracic wall, and the visceral pleura covers the lungs. The space between them contains lubricating fluid, which reduces friction during breathing.
Pleura
the physical process of moving air into and out of the lungs (breathing). It involves the mechanical actions of inspiration (inhalation) and expiration (exhalation).
Ventilation
smaller, highly branched tubes within the lungs that branch off the bronchi. Unlike the bronchi, they lack cartilage and have smooth muscle in their walls, allowing their diameter to be adjusted to regulate airflow to the alveoli.
Bronchioles
the process that occurs in the lungs (at the alveoli), involving the exchange of oxygen and carbon dioxide between the air in the alveoli and the blood flowing through the pulmonary capillaries.
External Respiration
two large chambers located behind the nose and above the roof of the mouth. They are lined with a mucous membrane and small hairs, serving to filter, warm, and moisten incoming air before it reaches the lower respiratory tract.
Nasal Cavities
the overall process by which the body exchanges gases with the environment. It encompasses three main stages: ventilation (breathing), external respiration (gas exchange in the lungs), and internal respiration (gas exchange in the tissues).
Respiration
the metabolic process that occurs within the cells of the body, where oxygen is used to break down glucose (sugar) and other nutrient molecules to release energy (ATP), producing carbon dioxide and water as byproducts.
Cellular Respiration
the process of moving air into the lungs. It is an active process involving the contraction of the diaphragm and external intercostal muscles, which increases the volume of the thoracic cavity and draws air into the lungs.
Inspiration
a wall of cartilage and bone that divides the inside of the nose into the two separate nasal cavities (right and left).
Nasal Septum
the biological system consisting of specific organs and structures (including the nose, pharynx, larynx, trachea, bronchi, and lungs) that facilitates the exchange of oxygen and carbon dioxide between the body and the external environment.
Respiratory System
microscopic, hair-like projections found on the surface of epithelial cells lining the trachea and bronchi. Their coordinated, sweeping motion helps to move mucus and trapped dust particles/pathogens upward and out of the respiratory tract (mucociliary escalator).
Cilia
the exchange of oxygen and carbon dioxide between the blood in the systemic capillaries and the tissue cells throughout the body. Oxygen leaves the blood, and carbon dioxide enters the blood.
Internal Respiration
the external structure that contains the nostrils (nares) and leads into the nasal cavities. It is the primary entrance for air into the respiratory system and is responsible for initial filtration.
Nose
air-filled cavities located in the bones surrounding the nasal cavity (frontal, sphenoid, ethmoid, and maxillary bones). They help to lighten the skull, warm and moisten air, and contribute to voice resonance.
Sinuses