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Chapter 25

ANAT 100 Chapter Notes - Chapter 25: Paranasal Sinuses, Bronchiole, Respiratory Epithelium


Department
Anatomy and Cell Biology
Course Code
ANAT 100
Professor
Leslie W Mac Kenzie
Chapter
25

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Module 9: Respiratory System
9.1 Proximal Respiratory System
Functions: primary function most of us associate with the respiratory system is breathing, also
termed pulmonary ventilation
gas conditioning: gases are warmed to body temp., humidified (moistened), and cleansed
of particulate matter through contact with the respiratory epithelium and its sticky
mucous covering
sound production: as air is forced out of lungs and moves through larynx, sound may be
produced, such as speech or singing
sense of smell: olfaction
defense: both the structure of the respiratory system and some of the cells within the
respiratory epithelium protect the body against infection by airborne molecules
continuous movement of gases into and out of lungs is necessary for the process of gas exchange
Functional regions:
Conducting portion: transports air
nose, nasal cavity, and pharynx of the upper respiratory tract and the larynx,
trachea, and progressively smaller airways (from the main bronchi to the terminal
bronchioles) of the lower respiratory tract
Respiratory portion: gas exchange with the blood occurs
composed of small airways called respiratory bronchioles and alveolar ducts as
well as air sacs called alveoli in the lower respiratory tract
Upper respiratory tract: nose and nasal cavity, paranasal sinuses, pharynx, and associated structures
Respiratory Tract Epithelium:
Ciliated pseudostratified columnar with goblet cells (R.T.E.)
Nose and Nasal Cavity: main conducting airway for inhaled air
supported superiorly by paired nasal bones that form the bridge of the nose
boundaries of nasal cavity:
internal surface of the nose leads to the nasal cavity
roof: frontal bone, nasal bones, cribriform plate of ethmoid, and sphenoid bone
hard palate (nasal cavity floor): palatine process of maxillae and horizontal plate
of the palatine bones
Structural components:
Vestibule: anterior region of the nasal cavity, near the nostrils
Conchae: paired, bony projections that subdivide the nasal cavity into separate
air passages (superior, middle, and inferior) (aka turbinate bones)
Histology:
Olfactory epithelium: both a pseudostratified ciliated columnar epithelium and
olfactory receptor cells; most superior part of the nasal cavity
R.T.E (respiratory tract epithelium): pseudostratified ciliated columnar
epithelium; within this epithelium are numerous goblet cells that produce mucin,
and immediately deep to this epithelium is an extensive vascular network
Paranasal Sinuses:
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Location: frontal, ethmoidal, sphenoidal, and maxillary sinuses (named for bones in
which they are housed)
Function: paired air spaces that together decrease skull bone weight
Histology: lined with the same pseudostratified ciliated columnar epithelium as the nasal
cavity
Pharynx (aka throat):
Function: funnel-shaped common space used by both respiratory and digestive systems
Boundaries and regions (naso, oro, laryngo): originates posterior to the nasal and oral
cavities and extends inferiorly to the level of the bifurcation of the larynx and esophagus
Histology: lined by a mucosa and contains skeletal muscles that are primarily used for
swallowing; flexible lateral walls distensible to force swallowed food into the esophagus
pharynx is partitioned into three adjoining regions:
nasopharynx: superiormost region of the pharynx, posterior nasopharynx wall
also houses a single pharyngeal tonsil
oropharynx: middle region, immediately posterior to the oral cavity; lymphatic
organs in oropharynx provide “first line of defense” against ingested or inhaled
foreign materials
palatine tonsils are on the lateral wall between the arches
lingual tonsils are at base of the tongue
laryngopharynx: inferior, narrowed region
Lower respiratory tract: made up of conducting airways (larynx, trachea, bronchi, bronchioles, and their
associated structures) as well as the respiratory portion of the respiratory system (respiratory bronchioles,
alveolar ducts, and alveoli)
Larynx (voice box):
somewhat cylindrical airway
continuous superiorly with the laryngopharynx and inferiorly with the trachea
Functions:
passageway for air
prevents ingested materials from entering the respiratory tract
produce sound for speech
assists in increasing pressure in the abdominal cavity
participate in both sneeze and cough reflex
Structure: formed and supported by a framework of nine pieces of cartilage that are held
in place by ligaments and muscles. Anatomic arrangement of nine cartilages:
thyroid*: largest laryngeal cartilage. shaped like a shield, it forms lateral and
anterior walls of larynx
cricoide*: ring-shaped, inferior to thyroid cartilage
epiglottis*: large, spoon-/leaf-shaped; closes over laryngeal inlet during
swallowing; anchored to inner aspect of thyroid cartilage and projects postero-
superiorly into pharynx
arytenoid, corniculate, cuneiform cartilages: paired located internally
* = single (not paired)
Cartilaginous box
Mucosal folds:
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