Ch 7.10 key terms
Alveoli
Tiny, grape-like air sacs at the end of the bronchioles (about 500 million in an adult lung). They are made of one layer of squamous epithelial tissue and are surrounded by capillaries. They are the site of gas exchange (oxygen and carbon dioxide) between the air and the blood.
Epiglottis
A leaf-like piece of cartilage that closes the opening to the larynx during swallowing. This prevents food and liquids from entering the respiratory tract.
Larynx
Located between the pharynx and the trachea. It contains the vocal cords and is responsible for speech (sound production).
Pharynx
Located behind the nasal cavities and divided into three sections (nasopharynx, oropharynx, and laryngopharynx). It is a passageway for both food and air.
Trachea
A tube extending from the larynx to the center of the chest. It carries air to the bronchi and is kept open by C-shaped cartilages.
Bronchi
The two divisions of the trachea (right and left) that carry air into the lungs. They continue to divide into smaller and smaller branches.
Expiration
The process of breathing out. The diaphragm and intercostal muscles relax, causing the chest cavity to decrease in volume, which forces air out of the lungs.
Lungs
Organs of respiration located in the thoracic cavity. They are divided into sections, or lobes (right lung has three, left lung has two), and are surrounded by the pleura.
Pleura
The double-membrane serous sac that covers the outside of the lungs and lines the chest wall. The pleural fluid lubricates the membranes, allowing the lungs to slide easily during breathing.
Ventilation
The process of breathing, which involves inspiration (inhalation) and expiration (exhalation).
Bronchioles
The smallest branches of the bronchi that end in the alveoli.
External Respiration
The exchange of oxygen and carbon dioxide between the alveoli (lungs) and the blood in the pulmonary capillaries.
Nasal Cavities
Hollow spaces lined with mucus membrane and a rich blood supply. They are responsible for warming, filtering, and moistening the air as it enters the body.
Respiration
The process of taking oxygen into the body and expelling carbon dioxide. It involves external, internal, and cellular respiration.
Cellular Respiration
The process by which cells use oxygen and nutrients (like glucose) to produce energy (ATP), water, and carbon dioxide (a waste product).
Inspiration
The process of breathing in. The diaphragm and intercostal muscles contract, which enlarges the thoracic cavity and draws air into the lungs.
Nasal Septum
The wall of cartilage that divides the nose into two hollow spaces, called the nasal cavities.
Respiratory System
The system consisting of the lungs and air passages. Its job is to take in oxygen and remove carbon dioxide, a necessary function for cellular respiration and life.
Cilia
Tiny, hair-like structures that line the nasal and bronchial passages. They move in waves to help push mucus, trapped pathogens, and other foreign particles toward the pharynx to be swallowed or expelled.
Internal Respiration
The exchange of oxygen and carbon dioxide between the blood in the systemic capillaries and the tissue cells of the body.
Nose
The structure that contains the nasal cavities and provides the entrance for air.
Sinuses
Cavities in the skull that surround the nasal area. They are connected to the nasal cavities by short ducts and are lined with a mucous membrane that warms and moistens air. They also provide resonance for the voice.