lower airway u larynx u tracheobronchial tree (tb tree) u trachea u bronchi u bronchioles u...
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Lower AirwayLower Airway
Larynx Tracheobronchial Tree (TB Tree)
Trachea Bronchi Bronchioles
Respiratory Terminal
Hyoid BoneHyoid Bone
Not part of the larynx. The Hyoid bone is an
anchor for the anterior muscles of the neck and is highly mobile. It also attaches to the muscles of the tongue to provide a stable or mobile base as the mobility of the tongue requires.
LarynxLarynx
Voice Box Function
Prevents aspiration Generates sound for speech Conducts air between the pharynx and
trachea Creates pressure changes
AspirationAspiration
Aspiration is the movement of food, liquid, vomit or a foreign substance into the trachea.
Aspiration usually involves coughing or choking until the substance is removed if the patient has intact reflexes
If large amounts of material or acidic, caustic materials (vomit) are aspirated, lung damage will result
Increased Risk of Aspiration
•Extremes of Age
•Recent Meal
•Delayed gastric emptying
•Trauma
•Depressed level of consciousness
•Poor motor control
Cartilages of the LarynxCartilages of the Larynx
Composed of nine cartilages
Three unpaired cartilage Thyroid (Greek for Oblong Shield) Cricoid (Greek for ring) Epiglottitis (Greek for “above glottis”)
Three paired cartilages (six total) Arytenoids (Greek for ladle) Corniculates (Latin for horns – cornucopia) Cuneiforms (Latin for wedge)
2. Arytenoid cartilage
3. Cervical trachea
6. Epiglottic larynx
7. Epiglottis
8. False Vocal Cords
9. Hyoid Bone
12. Subglottic larynx
15. True Vocal Cords
Paired CartilagesPaired Cartilages
The Arytenoids, Cuneiforms, and Corniculates are all associated with movement of the vocal cords and are used in phonation.
Thyroid CartilageThyroid Cartilage The largest laryngeal cartilage
is the thyroid cartilage “Adam’s Apple”
Superior border has a V-shaped notch.
Suspended from hyoid bone. Posterior wall is open. The true and false vocal cords
are found on the interior of the larynx.
Vocal CordsVocal Cords Two pairs of folds that protrude inward:
Upper pair – False cords Lower pair – True cords
The space between the vocal cords is called the rima glottidis or glottis Narrowest portion of the adult airway
Vocal CordsVocal Cords
Vocal CordsVocal Cords Vocal Cord Abduction
Cords are opening or moving away from the midline
This occurs during inspiration Vocal Cord Adduction
Cords are moving toward the midline or coming together
This occurs during expiration http://www.entusa.com/normal_larynx.htm
EpiglottisEpiglottis
Spoon-shaped cartilage which prevents aspiration by covering the opening of the larynx during swallowing.
The tongue and the epiglottis are connected by folds of mucous membranes which form a small space called the vallecula.
IntubationIntubation A device called a laryngoscope is used to
visualize the laryngeal structures. It is composed of a handle and one of two
types of blades: A curved blade (McIntosh) A straight blade (Miller or Wisconsin)
A straight laryngoscope blade is used to directlydirectly lift the epiglottis during intubation
A curved laryngoscope blade is inserted into the vallecula during intubation to lift the epiglottis indirectlyindirectly.
Cricoid CartilageCricoid Cartilage
Resembles signet (class) ring.
Inferior to Thyroid. Only complete ring of
laryngeal structures. Inferior border is attached
to the first C-shaped tracheal ring.
The narrowest portion of the airway in an infant. We use this fact when
ventilating infants as infant ET tubes do not have cuffs to seal the trachea.
Cricothyroid membraneCricothyroid membrane
Connects the cricoid and thyroid cartilages
Is the site for an emergency airway Cricothyrotomy
Laryngeal SwellingLaryngeal Swelling
Swelling (edema) at the glottis, subglottic or supraglottic region can cause stridor
Stridor is a high pitched crowing sound usually heard on inspiration from air traveling through a narrowed opening Croup, Epiglottis, Foreign Body
http://www.rale.ca/Stridor.htm
LaryngospasmLaryngospasm
A laryngeal reflex which will close the vocal cords inside the larynx
Laryngospasm results from Extubations Near drowning Inhalation of noxious substances Smoke inhalation
Valsalva ManeuverValsalva Maneuver
Forced expiratory effort against a closed glottis to increase intrathoracic pressure (defecation) or to inflate the eustachian tubes and middle ears (“clearing” of the ears on airplanes).
The larynx will tightly seal preventing air from escaping during physical work Lifting, pushing, throat-clearing, vomiting,
urination, defecation and parturition.
Head Head PositionPosition
FlexedFlexed
ExtendedExtended
Histology of the LarynxHistology of the Larynx
Above the vocal cords stratified squamous epithelium
Below the vocal cords pseudostratified columnar epithelium
Trachea to respiratory bronchioles
Tracheobronchial TreeTracheobronchial Tree Two Divisions
Cartilaginous Airways Primarily conducting airways; no gas exchange.
Noncartilaginous Airways Both conducting airways and sites of gas exchange.
Dichotomous Branching Each airway divides into two “daughter” branches Each division (bifurcation) gives rise to a new
generation of airways As airways divide, they become
Shorter Narrower More numerous
Cartilaginous AirwaysCartilaginous Airways
Trachea Main Stem Bronchi Lobar Bronchi Segmental Bronchi Subsegmental Bronchi
Lobar Bronchi
TracheaTrachea
Generation 0 11 – 13 cm long and 1.5 – 2.5 cm wide. Extends from Cricoid cartilage (6th cervical
vertebrae) to the 2nd costal cartilage or 5th thoracic vertebrae. C6 – T5
15 - 20 C-shaped cartilages supports the trachea.
Posterior wall is contiguous with esophagus.
TracheaTrachea The end of the trachea is called the carina.
This is the division of the trachea into the right and left mainstem bronchi.
Air is 100% saturated with water vapor and is warmed to 37 °C (body temperature).
The carina is located at approximately T5 or the Angle of Louis.
The surgical opening into the trachea is called a tracheostomy. 2nd or 3rd tracheal ring.
Main Stem BronchiMain Stem Bronchi
Generation 1 Trachea divides into the right and left mainstem
bronchi – one for each lung Right Mainstem is wider, shorter and more
vertical Branches at a 25 degree angle
Left Mainstem Branches at a 40 – 60 angle
Infants Both mainstem bronchi form a 55 angle with the
trachea
Newborn
Complications of IntubationComplications of Intubation
During intubations, if the tube is advanced to far, the tube will usually go into the right mainstem bronchi. Lung inflation will be absent on the left but present
on the right. Withdraw tube until bilateral sounds are heard.
Failure to hear lung sounds or visualize chest inflation on either side means the tube is probably in the stomach. Extubate the patient and re-attempt the intubation.
AspirationAspiration
Children who aspirate objects Foreign body usually lodged in right main
stem bronchi secondary to the angle being less acute.
Wheezing on right or absent lung sounds (breath sounds).
Lobar BronchiLobar Bronchi
Generation 2 Lobar Bronchi correlate to the number of
lobes of the lung. The right mainstem bronchi will divide into the
right upper, right middle and right lower lobe bronchi.
The left mainstem bronchi will divide into the left upper and left lower lobe bronchi.
Segmental BronchiSegmental Bronchi
Generation 3 Correlate with the segments of the lung. There are 10 segmental bronchi on the
right. There are 8 segmental bronchi on the
left.
Subsegmental BronchiSubsegmental Bronchi
4th to 9th Generations 1 to 4 mm in diameter Connective tissue containing:
Nerves Lymphatics Bronchial Arteries
Non-Cartilaginous AirwaysNon-Cartilaginous Airways Bronchioles
10th to 15th Generation. 1 mm in diameter. Simple cuboidal epithelium. No cartilage.
Terminal Bronchioles Less than 0.5 mm in diameter. No cartilage (lack of support). Cilia and mucous glands
disappear. Clara Cells appear Inter-bronchiole connections
called Canals of Lambert begin to appear.
Blood Supply to the Blood Supply to the Tracheobronchial TreeTracheobronchial Tree
Bronchial Blood Supply Bronchial arteries nourish the tracheobronchial tree The arteries arise from the aorta and follow the
tracheobronchial tree as far as the terminal bronchioles. Beyond the terminal bronchioles pulmonary arteries &
capillaries feed the airways & alveoli.
Normal bronchial blood flow is approximately 1% of the cardiac output.
Also feed the mediastinal lymph nodes, pulmonary nerves, part of the esophagus and the visceral pleura.
Review of TB TreeReview of TB Tree
Trachea Mainstm Bronchi Lobar Bronchi Segmental Bronchi Subsegmental Bronchi Bronchioles – cartilage disappears Terminal Bronchioles
Site of Gas ExchangeSite of Gas Exchange“The Respiratory Zone”“The Respiratory Zone”
Consists of the respiratory bronchioles, alveolar ducts, and alveolar sacs, and alveoli.
Parenchyma, Acinus or Primary Lobule.
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Attribution
Alveolar EpitheliumAlveolar Epithelium Two principal cell types:
Alveolar Type I Cells Squamous pneumocyte Broad thin cells. 95% of alveolar surface 0.1 to 0.5 thick
Alveolar Type II Cells 5% of alveolar surface Cuboidal in shape Responsible for secretion of pulmonary surfactant
that reduce surface tension and keep the alveoli stable.
Facts about the LungsFacts about the Lungs
There are 300 million alveoli in the lungs.
The surface area of the lungs is 75-85 square meters (Tennis Court).
The lung has 35 times more surface area then the skin.
Additional Components of Additional Components of Alveolar EpitheliumAlveolar Epithelium
Pores of Kohn Small holes in the walls of
interalveolar septa. 3 to 13 in diameter
Alveolar Macrophages or Type III alveolar cells. Major role in removing
bacteria and other foreign particles.
Interstitium Gel-like substance between
alveoli-capillary clusters that add support
LungLung Extends from the diaphragm to 1-2 cm
above the clavicles (about the 1st rib). The lung apex is at the top of the lung and
is somewhat pointed. The base is broad and concave and lies
at about the 6th rib or xiphoid process anteriorly, the 8th rib laterally, and the 11th rib posteriorly.
The right lung is larger and heavier than the left.
Lung Lobes and SegmentsLung Lobes and Segments
Right lung Three Lobes
Upper, Middle, Lower Divided by the Horizontal and Oblique fissures.
10 Segments
Left lung Two Lobes
Upper and Lower Divided by the Oblique fissures.
8 Segments
LOBES AND SEGMENTS OF THE LUNGS
RIGHT LUNG LEFT LUNG
UPPER LOBE UPPER LOBE (UPPER DIVISION)
• APICAL SEGMENT ANTERIOR SEGMENT
• POSTERIOR SEGMENT
•APICAL/POSTERIOR •ANTERIOR
MIDDLE LOBE UPPER LOBE (LINGULA)
•LATERAL •MEDIAL
•SUPERIOR •INFERIOR
LOWER LOBE LOWER LOBE
•SUPERIOR•ANTERIOR BASAL•MEDIAL BASAL•LATERAL BASAL•POSTERIOR BASAL
•SUPERIOR•ANTERIOR/MEDIAL BASAL •LATERAL BASAL•POSTERIOR BASAL
Lung FissuresLung Fissures
Oblique Fissure Found in the left and right lung Separates the upper and lower lobes of
both lungs Horizontal or minor Fissure
Found only in the right lung Separates the upper and middle lobes
Horizontal fissure
Oblique fissure
HilumHilum
The hilum is where arteries, veins, bronchi, nerves and lymph vessels enter and leave the lung.
It is located on the medial border of the lung.