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21 terms

Chapter 22: Respiratory System

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Respiration
Involves both the respiratory and the circulatory systems
4 processes that supply the body with oxygen and dispose of carbon dioxide
Respiratory System
Pulmonary ventilation (breathing)
External respiration: oxygen and carbon dioxide exchange in lungs
Circulatory System
Transport: oxygen and carbon dioxide in the blood
Internal respiration: oxygen and carbon dioxide exchanger in tissues
Nasal Mucosa
During inhalation: Filter, heat and moisten air
During exhalation: Reclaim heat and moisture (only some of the heat and moisture are reclaimed)-significant body heat can be lost during exhalation
Paranasal Sinuses
In frontal, sphenoid, ethmoid, and maxillary bones
Lighten the skull and help to warm and moisten the air
Larynx
Attaches to the hyoid bone
Continuous with the trachea
Functions: (1.) Air flow (2.) Routes air and food into proper channels (3.) Voice production
Cartilages of the larynx
Hyaline cartilage except for the epiglottis.
Thyroid cartilage with laryngeal prominence (Adam's apple).
Ring-shaped cricoid cartilage.
Paired arytenoid, cuneiform, and corniculate cartilages
Epiglottis
elastic cartilage; covers the laryngeal inlet during swallowing
Larynx
(a) Anterior superficial view
Epiglottis, Body of hyoid bone, Thyrohyoid membrane, Thryoid cartilage, Laryngeal prominence (Adam's apple), Cricothryoid ligament, Cricoid cartilage, Cricotracheal ligament, Tracheal cartilages
Vocal ligaments
Attach the arytenoid cartilages to the thyroid cartilage
Contain elastic fibers
Form core of vocal folds (true vocal cords): Opening between them is the glottis
Folds vibrate to produce sound as air rushed up from the lungs
Vestibular folds (false vocal cords)
Superior to the vocal folds
No part in sound production
Help to close the glottis during swallowing
Voice Production
Speech: intermittent release of expired air while opening and closing the glottis
Pitch is determined by the length and tension of the vocal cords
Loudness depends upon the force of air
Cambers of pharynx, oral, nasal, and sinus cavities amplify and enhance sound quality
Sound is "shaped" into language by muscles of the pharynx, tongue, soft palate, and lips
Larynx
Vocal folds may act as a sphincter to prevent air passage
Example: Valsalva's maneuver
Glottis closes to prevent exhalation
Abdominal muscles pressure rises
Helps to empty the rectum or stabilizes the trunk during heavy lifting
Trachea
Windpipe: from the larynx into the mediastinum
Wall composed of three layers
1. Mucosa: ciliated epithelium
2. Submucosa: connective tissue
3. Adventitia: outermost layer made of connective tissue that encases the C-shaped rings of hyaline cartilage
Trachealis muscle
Connects posterior parts of cartilage rings
Contracts during coughing to expel mucus
Carina
Last tracheal cartilage
Point where trachea branches into two bronchi
(a) Cross section of the trachea and esophagus
Esophagus
Bronchi and Subdivisions
Air passages undergo 23 orders of branching
Branching patter called the bronchial (respiratory) tree
Conduction Zone Structures
Trachea=> right and left main (primary) bronchi
Each main bronchus enters the hilum of one lung. Right main bronchus is wider, shorter, and more vertical than the left
Each main bronchus branches into lobar (secondary) bronchi (three right, two left). Each bronchus supplies one lobe
Each lobar bronchus branches into segmental (tertiary) bronchi. Segmental bronchi divide repeatedly
Bronchioles are less than 1 mm in diameter
Terminal bronchioles are the smallest, less than 0.5 mm diameter
From bronchi through bronchioles, structural changes occur: Cartilage rings give way to plates; cartilage is absent from bronchioles
Epithelium changes from pseudostratified columnar to cuboidal; cilia and goblet cells become sparse
Relative amount of smooth muscle increases
Lung
Respiratory Zone
Respiratory bronchioles, alveolar ducts, alveolar sacs (clusters of alveaoli)
~300 million alveoli account for most of the lungs' volume and are the main site for gas exchange

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