Transcript Lower Airway - Macomb

Lower Airway
Larynx
Tracheobronchial
Trachea
Bronchi
Bronchioles
Respiratory
Terminal
Tree (TB Tree)
Hyoid 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.
Larynx
 Voice
Box
 Function
 Prevents
aspiration
 Generates sound for speech
 Conducts air between the pharynx and
trachea
 Creates pressure changes
Aspiration



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 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 Cartilages
 The Arytenoids,
Cuneiforms, and
Corniculates are all associated with
movement of the vocal cords and are
used in phonation.
Thyroid Cartilage
 The
largest laryngeal cartilage
is the thyroid cartilage
 “Adam’s
 Superior
Apple”
border has a Vshaped notch.
 Suspended from hyoid bone.
 Posterior wall is open.
 The true and false vocal cords
are found on the interior of the
larynx.
Vocal Cords
 Two
pairs of folds that protrude inward:
pair – False cords
 Lower pair – True cords
 Upper
 The
space between the vocal cords is called the rima
glottidis or glottis
 Narrowest
portion of the adult airway
Vocal Cords
Vocal 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
Epiglottis
 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.
Intubation
 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 curved
laryngoscope
blade is inserted into
the vallecula during
intubation to lift the
epiglottis indirectly.

A straight laryngoscope blade is
used to directly lift the epiglottis
during intubation
Cricoid 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 membrane
 Connects
the cricoid
and thyroid cartilages
 Is the site for an
emergency airway
 Cricothyrotomy
Laryngeal 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
Laryngospasm
 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 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
Position
Flexed
Extended
Histology of the Larynx
 Above
the vocal cords
 stratified
 Below
squamous epithelium
the vocal cords
 pseudostratified
 Trachea
columnar epithelium
to respiratory bronchioles
Tracheobronchial 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 Airways
 Trachea
 Main
Stem Bronchi
 Lobar Bronchi
 Segmental Bronchi
 Subsegmental Bronchi
Lobar Bronchi
Trachea
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.

Trachea
 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 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

Left Mainstem
 Branches

at a 25 degree angle
at a 40 – 60 angle
Infants
 Both
mainstem bronchi form a 55 angle with the
trachea
Newborn
Complications 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.
Aspiration
 Children
 Foreign
who aspirate objects
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 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 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 Bronchi
 4th
to 9th Generations
 1 to 4 mm in diameter
 Connective tissue containing:
 Nerves
 Lymphatics
 Bronchial
Arteries
Non-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
Tracheobronchial 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 Tree
 Trachea
 Mainstm
Bronchi
 Lobar Bronchi
 Segmental Bronchi
 Subsegmental Bronchi
 Bronchioles – cartilage disappears
 Terminal Bronchioles
Site of Gas Exchange
“The Respiratory Zone”
 Consists
of the respiratory bronchioles,
alveolar ducts, and alveolar sacs, and
alveoli.
 Parenchyma, Acinus or Primary Lobule.
Creative Commons
Attribution
Alveolar Epithelium
 Two
principal cell types:
 Alveolar
Type I Cells
 Squamous
pneumocyte
 Broad thin cells.
 95% of alveolar surface
 0.1 m to 0.5 m thick
 Alveolar
 5%
Type II Cells
of alveolar surface
 Cuboidal in shape
 Responsible for secretion of pulmonary surfactant
that reduce surface tension and keep the alveoli
stable.
Facts 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
Alveolar Epithelium
 Pores
of Kohn
 Small
holes in the walls of
interalveolar septa.
 3 m to 13 m 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
Lung
 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 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 Fissures
 Oblique
Fissure
 Found
in the left and right lung
 Separates the upper and lower lobes of
both lungs
 Horizontal
 Found
or minor Fissure
only in the right lung
 Separates the upper and middle lobes
 Horizontal
fissure
 Oblique
fissure
Hilum
 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.