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The Head and Neck
Upper Respiratory Tract
Pg 583
The Nose
• Only external part of
respiratory tract
• Made of nasal bones,
connective tissue and
hyaline cartilage
• External Nares = Nostrils:
– openings into nasal cavity
• Internal Nares = Choanae:
– openings between nasal
cavity and nasopharynx
Entrance to the Nasal Cavity
• Vestibule –space just
inside external nares
• Skin lining contains:
– Sebaceous glands greasy secretion collect
dirt, lubricate, kill bacteria
– Sweat glands -acidic,
slows growth of bacteria
– Hair follicles –trap smaller
particles of dirt and dust
• Vibrissae – nose hairs
filtering larger particles
from air
Nasal Cavity
• Part of respiratory passage
• Boundaries
– Roof = ethmoid bone (cribiform plate)
– Floor = hard palate & soft palate
• Hard palate = maxilla (palatine process) + palatine (horizontal plate)
• Soft palate = skeletal muscle ending in uvula
– Lateral walls = nasal bones, superior+ middle nasal conchae
(ethmoid bone), inferior nasal conchae, maxilla, palatine
bone
– Nasal Septum = divides cavity into 2
• Vomer & Perpendicular Plate of Ethmoid
• Cartilage
Nasal Cavity
Pg 584
Nasal Cavity
• Functions
– Airway of respiratory tract
– Moisten and Warm air
– Filter air
– Resonating chamber for speech
– Houses olfactory receptors
Nasal Cavity (continued)
• Respiratory Mucosa–lines cavity walls, septum
– Ciliated psuedostratified columnar epithelium
w/lamina propria
• Mucous cells + serous cells
– Highly vascularized
• Moistens + warms inhaled air
– Highly innervated
• Cause sneeze reflex
• Olfactory Mucosa – on roof of nasal cavity,
contains the olfactory (smell) receptors
Nasal Conchae
• Project medially from each
lateral wall of nasal cavity
• Superior, Middle (ethmoid)
• Inferior nasal conchae
• Covered with Mucosa
• Functions
– Increase surface area
– Create turbulance
– Reclaim heat from exhaled air
Pg 584
Paranasal Sinuses
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Air-filled sacs surrounding nasal cavity
Extensions of nasal cavity, continuous with it
Same respiratory mucosal lining
In Frontal, Ethmoid, Sphenoid, Maxillae bones
Function: Warm + Filter air, Lightens skull
Pg 16
Mouth = Oral Cavity
• Opening of alimentary canal
• Lined with mucosa
• Thick, stratified squamous
epithelium (slightly
keratinized in some parts)
• Boundaries
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Pg 617
Anterior = lips
Lateral = cheeks
Posterior = oropharynx
Superior = palate
Inferior = tongue
Some Muscles of Face
• Lips (labia) + Cheeks: Keep
food in mouth during chewing
• Lips: Orbicularis oris
• Cheeks: Muscles of Mastication
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Temporalis
Masseter
Buccinator
Digastric
Pterygoids
Muscles of Mastication
Name
Origin
Insertion
Action
Innervation
Pterygoids
(med & lat)
Pterygoid plate
(sphenoid),
Maxilla, Palatine
bone
Mandible
Elevate &
Protract
Mandible
Trigeminal N.
(branch V3)
Digastric
Mandible, Mastoid
process (temporal)
Hyoid bone
(indirectly)
Elevate
hyoid,
Depress
mandible
Trigeminal N.
(branch V3)
Masseter
Zygomatic arch
and bone
Mandible
(angle and
ramus)
Elevates
mandible
Trigeminal N.
(branch V3)
Temporalis
Temporal bone
Coronoid
process of
mandible
(indirectly)
Elevates &
retracts
mandible
Trigeminal N.
(branch V3)
Palate
• Hard palate (anterior 2/3)
– Made of bone
– Covered with mucosa
– Tongue pushes food
against it during chewing
• Soft palate (posterior 1/3)
– Made of skeletal muscle
– Covered by mucosa
– Ends in the uvula
– Closes nasopharynx during
swallowing
Tongue
• Functions
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bitter
sour
Grips and moves food between teeth during chewing
Mixes food with saliva = BOLUS
Moves bolus down pharynx
Speech production
Houses taste buds (= gustation)
salty
• Creates floor of mouth
• Attachments: hyoid, mandible, styloid process, soft palate sweet
• Made of Skeletal muscle w/CT septum
– Intrinsic muscles
– Extrinsic muscles
• Innervation
– Motor = Hypoglossal (CN XII)
– Sensory = Mandibular (CN V3), Facial (CN VII), Glossopharyngeal (CN IX)
Pg 618
Salivary Glands
• Exocrine, tubuloalveolar glands
• Produce Saliva
– H2O, Ions, Mucus, Enzymes
• Internal salivary glands are small
– In mucosa of tongue, lips, palate, cheeks
– Keep areas wet
• External salivary glands are large, have ducts
– External to mouth
– Provide saliva when necessary or anticipated
– 2 Submandibular, 2 Sublingual, 2 Parotid glands
Salivary Glands
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•
Pg 618
Moisten mouth, wet food
Dissolve food to taste
Bind food together
Begin to break down starch
Neutralize mouth acid
Kill harmful microorganisms
Promote beneficial bacteria
Tiny Tabitha’s Teeth
The story of teeth from eruption to
edentate
Tiny Tabitha: Age 4 days
• Number of Erupted Teeth = 0
• Ultimate Goal = 32 Teeth
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Incisors (8): rip, cut
Canines (4): tear and pierce
Premolars (8): grinding
Molars (12): grinding
• Estimated Time of Completion
= 15-25 years
• Currently jaws covered by
gingiva (gum): is oral mucosa
= lots of drooling
Tabitha’s First Tooth
• Deciduous (Milk) = 20
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8 Incisors = 6-10 months
4 Canines = 16-20 months
4 1st Molars = 12-16 months
4 2nd Molars = 20-24 months
• Dental Formula: describes
number, kind & position of
teeth in ½ of the mouth
canines
Incisors
2:1:0:2
2:1:0:2
premolars
molars
X 2 = 20
Tabitha’s Teeth
• Function: Ingestion and
mechanical breakdown of
food
• Alveoli: sockets in
mandible and maxilla teeth
sit in
• Periodontal Ligament:
collagen fibers anchor
tooth in bony socket
– Gomphosis
• Cementum: calcified
connective tissue attaching
tooth to periodontal
ligament
Pg 620
Gross Anatomy of a Tooth
Pg 620
• Crown = area above gingiva
• Neck = (gumline) where crown and root meet
• Root = area below neck in alveolus
Tabitha’s Teeth Begin to
Tumble
• Around 7 years of age the
periodontal ligaments & roots of
deciduous teeth are eroded =
teeth fall out
• Permanent teeth begin to erupt
between 7-13 years
• 3rd Molars (Wisdom Teeth) may
not erupt until 17-25 years
• End Result: Adult Dental Formula
premolars
2:1:2:3
2:1:2:3
X 2 = 32
Tabitha’s Tooth Troubles
• College --> too much junkfood
= CAVITIES (caries)
• Bacteria erodes through the
outer enamel covering of tooth
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Avascular, Acellular
Mostly calcium salts
Not renewed or replaced
Hardest substance in body
• In severe cases it erodes the
deeper dentin of tooth
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Made of minerals & collagen
Is maintained during life
Harder than bone
Bulk of tooth
Pg 620
Tabitha’s Tooth Trauma!
• Most severe cases erosion penetrates
pulp cavity
– Center of tooth
– Pulp = loose CT w/ vessels & nerves
– Supplies nutrients to hard tissues
• Root canal: part of pulp cavity in root
• Apical Foramen: opening of pulp cavity
into root canal
• Artery: Sup/Inf Alveolar aa, branches of
Ext Carotid a
• Innervation:
– Maxilla = Superior Alveolar Nerves
– Mandible = Inferior Alveolar Nerves
Pg 620
Tabitha’s Teeth: the later years
• Tabitha graduates college, begins to take
better care of her teeth (i.e. consistent
brushing, flossing & dental visits), and leads
a normal happy tooth-filled life UNTIL………
• GINGIVITIS…..(inflammation of the gingiva
caused by plaque accumulation) leads to…..
Toodaloo Tabitha’s Teeth
• PERIODONTITIS
– Infection of periodontal
ligament leading to its
destruction and that of the
bone around teeth
– Leading to……..
• TOOTHLESSNESS!!!
Pharynx = “Throat”
• Connects nasal cavity &
mouth to esophagus & larynx
• Runs from skull to C6
• Carries food and air
• Lined with skeletal muscle
• Divided into 3 regions
– Nasopharynx
– Oropharynx
– Laryngopharynx
Pg 617
Tonsils
• Swellings of mucosal lining of
pharynx
• Simple lymph organs
– MALT: mucosa-associated lymphoid
tissue
• Form ring around opening of
pharynx
• 4 groups
Pg 570
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Palatine (pair)
Lingual
Pharyngeal
Tubal (pair)
Regions of the Pharynx
Nasopharynx
Oropharynx
Laryngopharynx
Pg 584
Nasopharynx: Only carries air
• Ciliated pseudostratified epithelium
• Location
– Posterior to Nasal Cavity
– Inferior to Sphenoid bone
– Superior to Soft Palate
• Closed off during swallowing by soft palate &
uvula
• Pharyngeal tonsils (adenoids)
• Tubal tonsils
Oropharynx: Carries Food & Air
• Thick, protruding stratified squamosal
epithelium due to great friction
• Location
– Posterior to Oral Cavity
– Runs from Soft Palate to Epiglottis
• Palatine tonsils
• Lingual tonsils
Laryngopharynx: Carries Food & Air
• Stratified squamosal epithelium
• Location
– Posterior to Larynx
• Continuous with esophagus (digestive system)
• Continuous with larynx (respiratory system)
Moving the Bolus
• Swallowing
– Voluntarily initiated (pharynx)
– Suprahyoid, Infrahyoid,
Pharyngeal constrictors
• Peristalsis = propulsion
Pg 611
– Involuntary
– Alternate waves of contraction
and relaxation of muscles in
organ walls (e.g. esophagus)
– Squeezes food from one organ
to next
– Some mixing
Hyoid Bone
• Only bone not directly articulated
with other bones
• Attaches via ligaments to temporal
bone, larynx
• Components
– Body
– Pair of Greater Horns
– Pair of Lesser Horns
• Functions
Pg 163
– Moveable base for tongue
– Attachment for sternohyoid, thyrohyoid
– Superior attachment for larynx
Larynx = “voicebox”
• Location: C4-6
– Low in neck for speech
• Attachments
– Superiorly = hyoid bone
– Inferiorly = trachea
• Innervation = vagus
• Functions
Pg 570
– Voice production
– Airway
– Routes food/air
Laryngeal Cartilages
• 9 Cartilages connected by ligaments & membranes
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1 Epiglottis
1 Thyroid
1 Cricoid
2 Arytenoid
2 Corniculate
2 Cuneiform
• Superior part = stratified squamosal epithelium
• Below vocal cords= ciliated pseudostratified columnar
Laryngeal Cartilages
• Epiglottis
– Elastic cartilage; Mucosa covering
– Projects upward from anterior wall of laryngeal inlet to level
of base of tongue
• Thyroid Cartilage
– Large, shield shaped, made of 2 plates
– Laryngeal prominence
• Cricoid Cartilage
– Shaped like signet ring
– Between thyroid cartilage and trachea
Laryngeal Cartilages
Pg 587
Vocal Cords
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Located in larynx
Vocal ligaments run from arytenoid and thyroid cartilages
Elastic fibers covered by mucosa
True vocal cords = Mucosal folds
Exhaled air passes over them causing vibration
– Force of air = volume
– Length & tension of folds = pitch
• “False” vocal cords = Vestibular folds
– lie superior to true pair, no role in voice production
Pg 588
The Vocal Cords
Thyroid cartilage
True Vocal Folds
Aretynoid cartilage
False Vocal Folds
True Vocal Folds
Thyroid Gland
• Location:
– Along trachea, just inferior to larynx
– “Butterfly” shape
Pg 718
• Endocrine Gland
– Thyroid hormone (TH): increases basal metabolic rate
– Calcitonin: depresses excessive levels of Ca2+ in blood
• Blood Supply:
– Superior thyroid arteries (branches of ext. carotids)
– Inferior thyroid arteries (branches of subclavians)
The Parathyroid Glands
• Usually 4
• Posterior thyroid
• Parathyroid hormone,
parathormone or PTH
– Increases Ca++ levels
in blood
Triangles of the Neck
Each half of the neck can be divided into 2 triangles:
1 Anterior and 1 Posterior
Anterior Muscles of the Neck
Name
Origin
Insertion
Action
Sternocleido- Manubrium, Mastoid proc.
Flex or rotate
mastoid
clavicle
(temporal bone), head
nuchal line
(occipital bone)
Sternohyoid
Innervation
Accessory n.
Manubrium, Hyoid bone
clavicle
Depress
C1-C3 spinal
larynx & hyoid nerves
Sternothyroid Manubrium Thyroid
cartilage of
larynx
Moves thyroid C1-C3 spinal
cartilage,
nerves
larynx, hyoid
inferiorly
Anterior Triangle of the Neck
• Boundaries
– Superior = Inferior margin of Mandible
– Anterior = Midline of Neck
– Posterior = Sternocleidomastoid muscle
• Contents
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Muscles: Suprahyoid, Infrahyoid
Artery: Carotid
Vein: Internal Jugular, External Jugular
Nerve: Accessory
Glands: Submandibular
Posterior Triangle of the Neck
• Boundaries
– Anterior = Sternocleidomastoid muscle
– Posterior = Trapezius muscle
– Inferior = Clavicle
• Contents
– Nerves: Phrenic, Accessory, Cervical Plexus,Brachial Plexus
– Artery: Subclavian
– Vein: External Jugular
Triangles of the Neck
pg 739