8 - Head and Neck Grays

7/27/2019 8 - Head and Neck Grays

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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
http://www.mc.vanderbilt.edu/.../Respiratory03.htmhttp://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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Cricoid

Inferior to thyroid cartilage

Forms a complete ring

Directly superior to trachea

pg 998


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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

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8 - Head and Neck Grays

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