Transcript Anatomy of the Respiratory System

Anatomy & Physiology
Chapter 23
Functions
Major functions
 Air distributor

All parts except
alveoli
 Gas exchanger

Alveoli
 Other functions
 Filters, warms &
humidifies the air
 Influence sound
production
 Makes sense of
smell possible
 Regulation of pH
in body
Divisions
 Upper respiratory
tract: those organs
outside of thorax
 Nose
 Nasopharynx
 Oropharynx
 Laryngopharynx
 Larynx
 Lower respiratory
tract: those organs
located almost
entirely within
thorax
 Bronchial tree
 Lungs
Nose
 Ala: flaring cartilaginous
expansion on each side of
nostril
 Nasal cavity separated by
the septum into left &
right cavities
 Each nasal cavity divided
into three passageways
(superior, middle, inferior
meati) by projection of
turbinates
Nose…..
 Anterior nares: external openings of
nose
 Vestibule: area just inside the nasal
cavity which contains vibrissae (hairs),
glands
 Posterior nares: openings that allow air
to pass from nasal cavity to pharynx
 Anterior naresvestibuleinferior,
middle, superior meatiposterior nares
Nasal mucosa
Respiratory mucosa lined with
pseudostratified columnar
epithelium
Has rich blood supply esp. over
inferior turbinate
Paranasal sinuses
 Air containing
spaces that open
into nasal cavity
 4 pairs
 Frontal
 Maxillary
 Ethmoid
 Sphenoid
Functions of Nose
Air passageway
Warms, moistens, filters air
Sinuses act to provide resonance for
voice
Pharynx
 Extends from base of skull to
esophagus
 Made of muscle & lined with
mucous membrane
 3 divisions
 Nasopharynx: from
posterior nares to soft
palate
 Oropharynx: from soft
palate to hyoid bone
 Laryngopharynx: from
hyoid bone to esophagus
Functions of the Pharynx
Common passageway for
respiratory & digestive tracts
Affects speech
Larynx
Voice box
Lies between root of tongue &
upper end of trachea
Structure of larynx
 Triangular shaped, primarily
of cartilage
 Mucous membrane lining
the larynx forms 2 pairs of
folds
 Vestibular (false) vocal folds:
upper pair
 True vocal cords
 Rima glottidis: opening
between true vocal cords;
narrowest part of larynx
 Glottis: true vocal cords &
rima glottidis
Cartilages of Larynx
 Nine cartilages
 Three largest: thyroid,
epiglottis, cricoid are
single structures, other 3
are paired
 Thyroid: Adam’s apple,
largest
 Epiglottis: leaf shaped,
moves up & down during
swallowing to prevent food
from entering trachea
 Aretynoid: point of
attachment for vocal cords
Muscles of larynx
 Intrinsic muscles: have both origin &
insertion on larynx
 Important in controlling vocal cord length
& in regulating shape of laryngeal inlet
 Extrinsic muscles: insert on larynx but
have their origin on other structures
 Moves or displaces larynx as a whole
Functions of larynx
Air passageway
Filters, warms, humidifies air
Protects airway against entrance of
solid or liquids
Voice production
Trachea
 Windpipe
 Extends from larynx
to bronchi
 About 1” (2.5 cm) in
diameter
 Made of C shaped
rings of cartilage,
incomplete on
posterior surface
Function of Trachea
Air passageway
Structure of bronchi
 Trachea divides at lower end into two primary
bronchi
 Rt bronchus slightly large & more vertical than
left
 Made of C shaped cartilage rings that become
complete within lungs
 Primary bronchi divide into secondary bronchi
which ultimately divide into small bronchioles
then finally into alveolar ducts
Structure of bronchi
 Cartilaginous rings become irregular in
secondary/tertiary bronchi
 Cartilaginous rings disappear in
bronchioles
 Alveolar ducts are single layer of simple
squamous epithelium
Structure of alveoli
 Resembles cluster of
grapes with alveolar duct
as stem and alveoli the
grapes
 Respiratory membrane:
barrier across which gas is
exchanged
 Surfactant: fluid inside
each alveoli, prevents
alveoli form collapsing as
air moves in and out
Structure of the lungs
 Cone shaped
 Extend from diaphragm to slightly above the
clavicles & lie against ribs
 Medial surface of lungs are concave but more
concave on left because of heart
 Bronchi and pulmonary vessels enter each
lung through a slit on medial surface called
the hilus
Surfaces of lungs
Base: inferior surface that rests on
diaphragm
Apex: pointed upper margin
Costal surface: lies against ribs
Lobes of lungs
 Left lung: 2 lobes & 2
secondary bronchi
 Superior and inferior
 Right lung: 3 lobes & 3
secondary bronchi
 Superior, middle, inferior
 Oblique fissure present in
both lungs
 Horizontal fissure: only
in right lung, separates
superior from middle
Functions of the lungs
Air distribution
Gas exchange
Structure of the thoracic
cavity
 Parietal pleura: lines the entire
thoracic cavity
 Visceral pleura: covers the outer
surfaces of the lungs
 Pleural space: area between parietal &
visceral pleura, contains small amount
of pleural fluid for lubrication