BISC 3221 Chapter Notes - Chapter 24: Mechanoreceptor, Phospholipid, Submucosa
16 Aug 2018
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Chapter 24: The Respiratory System
24.1 An Overview of the Respiratory System and Respiratory Tract
• Respiratory system: nose + nasal cavity + sinuses + pharynx + larynx + trachea + smaller
conducting passageways
o Includes respiratory tract and associated tissues/organs/support structures
• Upper respiratory system: nose + nasal cavity + paranasal sinuses + pharynx
o Condition air (warm, filter, humidify) to protect more delicate portion of tract
• Lower respiratory system: larynx + trachea + bronchi + lungs
Functions of the Respiratory System
• Provide area for gas exchange between air and circulating blood
• Move air to/from exchange surfaces of lungs
• Protect respiratory surfaces from dehydration, temp changes, environmental varation
• Defend respiratory system + other tissues from pathogen invasion
• Produce sounds for speaking/singing/nonverbal communication
• Regulate blood volume, blood pressure, body fluid pH
• Respiratory tract: airways that carry air to/from gas exchange surfaces
o Conducting portion: from entrance to smallest bronchioles
o Respiratory portion: respiratory bronchioles + alveoli
The Respiratory Epithelium
• Pseudostratified ciliated columnar epithelium with many mucous cells
• Lines the entire respiratory tract EXCEPT FOR parts of pharynx, smallest conducting passages,
alveoli
o Parts of pharynx are lined by stratified squamous epithelium to protect it from
abrasion/chemical attack
• Cilia in nasal cavity sweep microorganisms/debris trapped in mucous towards pharynx for
swallowing
• In lower portions of respiratory tract, cilia beat towards pharynx
• Respiratory defense system = respiratory filtration mechanisms
o All particles larger than 10 micrometers are removed in nasal cavity by vibrissae
o Small particles are trapped by mucous or pharynx secretions
o Exposure to unpleasant stimuli increases mucous production
• Filtration, warming, humidification of inhaled air occur throughout conducting portion of
respiratory system but biggest changes occur in nasal cavity; breathing through mouth doesn’t
have this
24.2 The Upper Respiratory System
The Nose and Nasal Cavity
• Nose is primary passageway for entering air
• Air enters though external nares which open into nasal cavity
• Nasal vestibule: portion of cavity enclosed by flexible tissues of nose, supported by thin
cartilages, contain coarse hairs to trap large particles
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• Nasal septum: separates right and left portions of nasal cavity; hyaline cartilage, supports dorsum
(bridge) and apex (tip) of nose
• Mucous produced in paranasal sinuses
• Olfactory region contains areas lined by olfactory epithelium: interior surface of cribriform plate,
superior nasal conchae of ethmoid, superior portion of nasal septum
• Air flows between adjacent conchae through superior middle or inferior meatuses to reach
internal nares
o Meatuses are narrow grooves, creates air turbulence to trap particles
• Hard palate: formed by maxillary and palatine bones, base of nasal cavity
• Soft palate: marks boundary between superior nasopharynx and rest of pharynx
The Pharynx
• Shared by respiratory and digestive tracts
• Extends between internal nares and entrances to trachea/esophagus
• 3 regions; nasopharynx, oropharynx, laryngopharynx
• The Nasopharynx
o Superior portion of pharynx, connected to nasal cavity by internal nares
o Separated from oral cavity by soft palate
o Lined by respiratory epithelium, lateral walls contain auditory tube openings
• The Oropharynx
o Between soft palate and base of tongue at level of hyoid bone
o Connected to posterior of oral cavity, posterior and inferior portions of nasopharynx
o Epithelium changes to nonkeratinized stratified squamous epithelium
o Posterior margin of soft palate supports uvula and pharyngeal arches
o Palatine tonsil on either side between anterior palatoglossal arch and posterior
palatopharyngeal arch
o Fauces: passageway between oral cavity and oropharynx
• The Laryngopharynx
o Region of pharynx between hyoid bone and entrance to esophagus
o Lined by nonkeratinized stratified squamous epithelium
24.3 The Lower Respiratory System
The Larynx
• Glottis: narrow opening between pharynx and larynx
• Larynx: begins at vertebra C3 or C4 and ends at C7
• Cartilages of the Larynx
o 3 unpaired cartilages: thyroid, cricoid, epiglottis
o Thyroid and cricoid cartilages are hylaline; epiglottis is elastic
• The Thyroid Cartilage
o Largest laryngeal cartilage AKA Adam’s apple
o Incomplete posteriorly
o Laryngeal prominence: thick ridge on anterior surface
o Inferior surface articulates with cricoid; superior surface has ligaments to epiglottis
• The Cricoid Cartilage
o Inferior to thyroid cartilage
Document Summary
24. 1 an overview of the respiratory system and respiratory tract. Chapter 24: the respiratory system: respiratory system: nose + nasal cavity + sinuses + pharynx + larynx + trachea + smaller conducting passageways. Incomplete posteriorly: laryngeal prominence: thick ridge on anterior surface. Inferior surface articulates with cricoid; superior surface has ligaments to epiglottis: the cricoid cartilage. 24. 6 the lungs: lungs are found in left and right pleural cavities, apex: tip, blunt cone shape, points superiorly, extends into the base of neck, base: broad, concave, inferior portion, rests on superior surface of diaphragm. Intrapulmonary bronchi: branches that extend past primary bronchi: primary bronchi divide to form secondary bronchi aka lobar bronchi. The blood supply to the lungs: pulmonary arteries enter lungs at hilum, branch with bronchi until lobules. 24. 8 respiratory muscles and pulmonary ventilation: pulmonary ventilation = breathing, physical movement of air in and out of bronchial tree, maintains adequate alveolar ventilation, prevents buildup of co2.
