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The Head and Neck
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Upper Respiratory Tract
Nose
Nostril
Nasal Cavity
Oral Cavity
Pharynx
pg 992
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Nose
Nose is the only portion of the RT that isexternally visible CT, bone, hyaline cartilage
Air enters here during breathing
Passes through the external nares (nostrils)
pg 1023
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Vestibule
Superior to nostrils Skin lined with:
Sebaceous glandsGreasy secretion
Collect dirt
Lubricate Kill bacteria
Sweat glandsAcidic
Slows growth of bacteria
Hair follicles Trap small particles of dirt
VibrissaeNose hairs
Filter large particles (insects)pg 1013
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Nasal Cavity
Functions:Provides airway for respiration
Moistens and warms airFilters inhaled airResonating chamber for speechHouses olfactory receptors
2 divisions:External nose
Internal nasal cavity
pg 1023
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Nasal Cavity
Divided into R and L by nasal septum
Continuous with the nasopharynx
through the internal nares (choanae)
pg 992
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Nasal Cavity
Boundries:Roof ethmoid bone (cribiform plate)
Floor maxilla (palatine process)
palatine (horizontal plate)
Lateral walls nasal bones, superior and middle nasalconchae of ethmoid bone, inferior nasal conchae,maxilla, palatine bone
Hard palatePalatine bones and maxillary bone
Soft palateSkeletal muscle posterior portion
End in uvula
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Lining of the Nasal Cavity
Respiratory Mucosa
Pseudostratified ciliated columnar epithelium
Goblet cells
Lamina propria
Mucous and serous cellsVenous plexus
Function is to filter and warm inhaled air
Highly innervated Sneeze!
Olfactory MucosaRoof of nasal cavity
Houses smell receptors
No goblet cells
Cilia modified for olfaction
www.mc.vanderbilt.edu/.../Respiratory03.htm
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Nasal Conchae
Project medially from each lateral wall
3 structures:
Superior of ethmoid bone
Middle of ethmoid bone
Inferior
Functions:Create turbulence to increase:
Filters air
Heats air
Moistens air
Reclaim heat and moisture during exhalation
pg 1023
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Paranasal Sinuses
Air filled cavities that
surround the nasal
cavity
Lined by mucosa Perform same function
as nasal cavity and
lightens skull
Located in Frontal,
Ethmoid, Sphenoid,
Maxilla bonespg 1018
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Pharynx
Connects the nasal cavity and mouth to
larynx and esophagus
Extends from base of skull to level of C6
vertebraCommon passage for food and air
Lined with skeletal muscle
Divided into:Nasopharynx
Oropharynx
Laryngopharynxpg 992
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Tonsils
Lymphoid organ
MALT
Swellings of the mucosa lining the pharynx
Form ring around the entrance to the pharynx
4 groups:
Palatine
Lingual
PharyngealTubal
Remove pathogens pg 992
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Oropharynx
Location:
Posterior to the oral cavity
Extends inferiorly from level of the soft palate to level ofthe esophagus
Swallowed food and inhaled air pass through here Stratified squamous epithelium
Contain:
Palatine tonsils
Lingual tonsils
pg 992
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Laryngopharynx
Location:
Lies posterior to larynx
Continuous with the esophagus and larynx
Common passageway for food and airFood esophagus
Air - larynx
Stratified squamous epithelium
pg 992
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Larynx Voice box
Extends from C4 to C6
Attachments:
Hyoid bone superiorly
Continuous with trachea inferiorly Functions:
Vocalization
Provides open airway
Switches to route air and food into proper channels
Innervation: Vagus
Superior part = stratified squamous epithelium
Below vocal cords= ciliated pseudostratified columnar
pg 1001
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Larynx All hyaline cartilage except epiglottis
Composed of 9 cartilages connected by membranes and ligaments: 1 Thyroid
1 Cricoid
1 Epiglottis
2 Arytenoid
2 Corniculate
2 Cuneiform
pg 1000
pg 1001
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Laryngeal Cartilages
Thyroid Cartilage
Large
Shield shaped
Formed by 2 plates
Contains laryngeal prominence
Adams Apple!!
pg 998
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Laryngeal Cartilages
Cricoid
Inferior to thyroid cartilage
Forms a complete ring
Directly superior to trachea
pg 998
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Laryngeal Cartilages
Epiglottis
Composed of elastic cartilage
Covered by mucosa
Projects upward from anterior wall of laryngeal inlet tolevel of base of tongue
Close off larynx during swallowing
pg 999
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Vocal Cords
Located in the larynx
Mucosal folds formed by vocal ligaments
Composed of elastic fibers
Run from arytenoid cartilages (posterior) to the thyroid cartilages
(anterior)
Exhaled air passes over them and causes vibration
Force of air = volume
Length & tension of folds = pitch
False vocal cords
Vestibular folds (superior to true)
pg 1008
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Thyroid Gland
Location: In anterior neck
On trachea, inferior to larynx
2 lateral lobes
Connected by the isthmusButterfly shape
Largest endocrine gland in bodyProduces Thyroid hormone (TH)
Increases metabolic rate
CalcitoninDepresses excess levels of Ca+ in blood
pg 966
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Thyroid Gland
Internally, composed of follicles
Follicular cells
TH
Parafollicular cellsCalcitonin
Blood supply
Superior thyroid arteries
Branches of external carotids
Inferior thyroid arteries
Branches of subclavians
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Parathyroid Gland
Two pairs
Located on the deep surface of the lateral lobes
of the thyroid gland
Produce parathyroid hormoneIncreases blood calcium levels
pg 966
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Mouth - Oral Cavity
Food enters alimentary canal through here
Mucosa-lined
Thick stratified squamous epithelium, with keratinization insome areas
Boundaries: Lips anteriorly
Cheeks laterally
Palate superiorly
Tongue inferiorly
Oropharynx posteriorly
Mouth divided into 2 parts:
Vestibule
Oral cavity proper
pg 1041
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Mouth
Lips (labia) and CheeksKeep food inside mouth during chewing
Composed of skeletal muscle surrounded by skin
Lips formed by orbicularis oris muscle
Cheeks; Muscles of Mastication Temporalis & Masseter (elevate mandible, close mouth)
Buccinator (chewing)
Digastric (lower mandible against resistance, opens mouth)
Pterygoids (lateral movements)
Palate: forms the roof of the mouthSoft palate (posterior) rises to close off nasopharynx
during swallowing; made of skeletal muscle
Hard palate (anterior) provides surface for tongue to forcefood against during chewing
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Tongue
Functions Grips and moves food between teeth
during chewing
Mixes food with saliva = BOLUS
Moves bolus down pharynx Speech production
Houses taste buds (= gustation)
Creates floor of mouth
Attachments: hyoid, mandible, styloid process, soft palate
Made of Skeletal muscle with a CT septum Intrinsic muscles (change shape; rolling) Extrinsic muscles (movement; protrude, retract)
Motor = Hypoglossal (CN XII)
Sensory = Mandibular (CN V3), Facial (CN VII), Glossopharyngeal (CN IX)
pg 1037
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Moving Bolus
Swallowing voluntarily initiated (pharynx)
Peristalsis = propulsion
Involuntary
Alternate waves of contraction and relaxation of muscles
in organ walls (e.g. esophagus)
Squeezes food from one organ to next
Some mixing
www.answers.com
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Salivary Glands
Compound tubuloalveolar glands
Intrinsic salivary glands
In mucosa of tongue, palate, lips and cheeks
Keeps mouth moist at all times
Extrinsic salivary glands
Lie external to mouth
Connected by ducts
Secrete only during eating or prior to (mouth watering)
3 paired glands:
Parotid
Submandibular sublingual
pg 863
pg 1043
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Salivary Glands
Produce saliva
Mixture of water, ions, mucus and enzymes
Moistens mouth
Dissolves food for taste
Binds food into a bolus
Enzymes digest starch
Bicarbonate buffer neutralizes acids
Kill microorganisms
Contains proteins to promote growth of beneficial bacteria
pg 1046
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Teeth From Eruption to Edentate
Function: Ingestion and mechanical breakdown of food
Have 2 sets of teeth (dentitions)
Primary dentition / deciduous (milk) teeth
Permanent dentition
Incisors: rip, cut
Canines: tear and pierce
Premolars: grinding
Molars: grinding
pg 1056
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Teeth
Gomphosis
Synarthrosis
Peg in socket with ligament
The sockets (alveoli) are in gum-coveredmargins in mandible and maxilla
Periodontal ligaments (collagen fibers) anchor
tooth in bony socket
Continous with gingiva (gum)
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Teeth Substances
EnamelMade of calcium salts
Avascular, acellular
Not renewed or replaced
HARDEST substance in body!!!!
DentinUnderlines enamel
Forms bulk of tooth
Made of minerals and collagen
Maintained during life
Harder than bone
CementumCalcified external surface
Attaches tooth to periodontal ligament
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Teeth
Regions:
Crown
Covered with enamel
Projecting into oral cavity
Neck (gumline)Root
Area beyond neck in alveolus
Pulp cavity
Center of tooth Loose CT with vessels and nerves
Supplies nutrients to hard tissues
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Teeth
Root Canal Portion of the pulp cavity in the root
Apical foramen
Opening into the root canal at the tip of each root
Blood supply Superior/Inferior Alveolar artery, branches of External Carotid artery
Innervation
Maxilla = Superior Alveolar Nerves
Mandible = Inferior Alveolar Nerves
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Teeth at Birth
Number of erupted teeth = 0
Jaws covered by gingiva (gums)
Lots of drooling!!!
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First Teeth 6 Months
Lower central incisors first to appear
8 Incisors = 6-10 months
4 Canines = 16-20 months
4 1st Molars = 12-16 months
4 2nd Molars = 20-24 months
20 deciduous teeth emerge by age 2 Dental formula
Describes the number and position of classes of teeth (half of themouth)
2I, 1C, 2M2I, 1C, 2M X 2 = 20
****No premolars!
Deciduous teeth dental formula:
pg 1056
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Adolescence Adult
Permanent teeth enlarge and developRoots of deciduous teeth reabsorbed
Teeth loosen and fall out
Begin to erupt from 7-13 years of age
Third molars (wisdom teeth) emerge from 17-25 yearsMay be absent!!
Adult dental formula:
2I, 1C, 2P, 3M
2I, 1C, 2P, 3MX 2 = 32
pg 1056
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Tooth Troubles
Gingivitis
Inflammation of the gingiva caused by plaque
accumulation
Leads to.
Periodontitis
Infection of periodontal ligament leading to its
destruction along with the bone around the teeth
Leads to toothlessness!
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Triangles of the Neck
Neck subdivided into two triangles
Separated by the sternocleidomastoid
muscle
Anterior triangle
Posterior triangle
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Triangles of the Neck: Posterior
Boundries:
Anterior - sternocleidomastoid
Posterior - trapezius
Inferior clavicle
Contents:
Nerves: accessory nerve, phrenic nerve, brachial
plexus
Artery: SubclavianVein: External jugular
pg 948
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Triangles of the Neck: Anterior
Boundries:
Anterior - midline
Posterior - sternocleidomastoid
Superior inferior margin of the mandible
Contents:
Glands: Submandibular
Muscles: Suprahyoid and infrahyoid muscles
Artery: Common carotid
Vein: Internal jugular, External jugular
Nerve: Accessory
pg 954