The head and neck
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The Head and Neck. Nose Nostril Nasal Cavity Oral Cavity Pharynx. Upper Respiratory Tract. pg 992. Nose is the only portion of the RT that is externally visible CT, bone, hyaline cartilage Air enters here during breathing Passes through the external nares (nostrils). Nose. pg 1023.

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The Head and Neck

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The head and neck

The Head and Neck

Upper respiratory tract



Nasal Cavity

Oral Cavity


Upper Respiratory Tract

pg 992

The head and neck

Nose is the only portion of the RT that is externally visible

CT, bone, hyaline cartilage

Air enters here during breathing

Passes through the external nares (nostrils)


pg 1023


Superior to nostrils

Skin lined with:

Sebaceous glands

Greasy secretion

Collect dirt


Kill bacteria

Sweat glands


Slows growth of bacteria

Hair follicles

Trap small particles of dirt


Nose hairs

Filter large particles (insects)


pg 1013

Nasal cavity

Nasal Cavity

  • Functions:

    • Provides airway for respiration

    • Moistens and warms air

    • Filters inhaled air

    • Resonating chamber for speech

    • Houses olfactory receptors

  • 2 divisions:

    • External nose

    • Internal nasal cavity

pg 1023

Nasal cavity1

Divided into R and L by nasal septum

Continuous with the nasopharynx through the internal nares (choanae)

Nasal Cavity

pg 992

Nasal cavity2

Nasal Cavity

  • Boundries:

    • Roof – ethmoid bone (cribiform plate)

    • Floor – maxilla (palatine process)

      palatine (horizontal plate)

    • Lateral walls – nasal bones, superior and middle nasal conchae of ethmoid bone, inferior nasal conchae, maxilla, palatine bone

  • Hard palate

    • Palatine bones and maxillary bone

  • Soft palate

    • Skeletal muscle posterior portion

    • End in uvula

Lining of the nasal cavity

Respiratory Mucosa

Pseudostratified ciliated columnar epithelium

Goblet cells

Lamina propria

Mucous and serous cells

Venous plexus

Function is to filter and warm inhaled air

Highly innervated


Olfactory Mucosa

Roof of nasal cavity

Houses smell receptors

No goblet cells

Cilia modified for olfaction

Lining of the Nasal Cavity

Nasal conchae

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

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 bones

Paranasal Sinuses

pg 1018


Connects the nasal cavity and mouth to larynx and esophagus

Extends from base of skull to level of C6 vertebra

Common passage for food and air

Lined with skeletal muscle

Divided into:





pg 992


Lymphoid organ


Swellings of the mucosa lining the pharynx

Form ring around the entrance to the pharynx

4 groups:





Remove pathogens


pg 992



Posterior to nasal cavity

Inferior to sphenoid bone

Superior to level of soft palate

ONLY an air passageway

Closed off during swallowing by the soft palates’ uvula


Ciliated pseudostratified epithelium


Pharyngeal tonsils (adenoids)

Tubal tonsils


pg 992



Posterior to the oral cavity

Extends inferiorly from level of the soft palate to level of the esophagus

Swallowed food and inhaled air pass through here

Stratified squamous epithelium


Palatine tonsils

Lingual tonsils


pg 992



Lies posterior to larynx

Continuous with the esophagus and larynx

Common passageway for food and air

Food – esophagus

Air - larynx

Stratified squamous epithelium


pg 992


“Voice box”

Extends from C4 to C6


Hyoid bone superiorly

Continuous with trachea inferiorly



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


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 1001

pg 1000

Laryngeal cartilages

Thyroid Cartilage


Shield shaped

Formed by 2 plates

Contains laryngeal prominence

Adam’s Apple!!

Laryngeal Cartilages

pg 998

Laryngeal cartilages1


Inferior to thyroid cartilage

Forms a complete ring

Directly superior to trachea

Laryngeal Cartilages

pg 998

Laryngeal cartilages2


Composed of elastic cartilage

Covered by mucosa

Projects upward from anterior wall of laryngeal inlet to level of base of tongue

Close off larynx during swallowing

Laryngeal Cartilages

pg 999

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)

Vocal Cords

pg 1008

Thyroid gland


In anterior neck

On trachea, inferior to larynx

2 lateral lobes

Connected by the isthmus

Butterfly shape

Largest endocrine gland in body

Produces Thyroid hormone (TH)

Increases metabolic rate


Depresses excess levels of Ca+ in blood

Thyroid Gland

pg 966

Thyroid gland1

Internally, composed of follicles

Follicular cells


Parafollicular cells


Blood supply

Superior thyroid arteries

Branches of external carotids

Inferior thyroid arteries

Branches of subclavians

Thyroid Gland

Parathyroid gland

Two pairs

Located on the deep surface of the lateral lobes of the thyroid gland

Produce parathyroid hormone

Increases blood calcium levels

Parathyroid Gland

pg 966

Hyoid bone


Inferior to mandible

In anterior neck

Associated with the skull

Only bone in skeleton that does not articulate directly to another bone!!!

Attaches via ligaments to temporal bone, larynx

Composed of:


2 pairs of horns


Moveable base for tongue

Points of attachment for larynx and neck muscles

Sternohyoid, thyrohyoid,

Hyoid Bone

pg 803

Oral cavity and associated organs




External Salivary glands

Oral Cavity and Associated Organs

pg 992

Mouth oral cavity

Food enters alimentary canal through here


Thick stratified squamous epithelium, with keratinization in some areas


Lips anteriorly

Cheeks laterally

Palate superiorly

Tongue inferiorly

Oropharynx posteriorly

Mouth divided into 2 parts:


Oral cavity proper

Mouth - Oral Cavity

pg 1041



  • Lips (labia) and Cheeks

    • Keep 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 mouth

    • Soft palate (posterior) rises to close off nasopharynx during swallowing; made of skeletal muscle

    • Hard palate (anterior) provides surface for tongue to force food against during chewing



  • 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

Moving bolus

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

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:




pg 1043

Salivary Glands

pg 863

Salivary glands1

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

Salivary Glands

pg 1046

Teeth from eruption to edentate


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

Teeth – From Eruption to Edentate

pg 1056




Peg in socket with ligament

The sockets (alveoli) are in gum-covered margins in mandible and maxilla

Periodontal ligaments (collagen fibers) anchor tooth in bony socket

Continous with gingiva (gum)


Teeth substances


Made of calcium salts

Avascular, acellular

Not renewed or replaced

HARDEST substance in body!!!!


Underlines enamel

Forms bulk of tooth

Made of minerals and collagen

Maintained during life

Harder than bone


Calcified external surface

Attaches tooth to periodontal ligament

Teeth Substances




Covered with enamel

Projecting into oral cavity

Neck (gumline)


Area beyond neck in alveolus

Pulp cavity

Center of tooth

Loose CT with vessels and nerves

Supplies nutrients to hard tissues



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


Maxilla = Superior Alveolar Nerves

Mandible = Inferior Alveolar Nerves


Teeth at birth

Number of erupted teeth = 0

Jaws covered by gingiva (gums)

Lots of drooling!!!

Teeth at Birth

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 the mouth)

2I, 1C, 2M

2I, 1C, 2M

First Teeth – 6 Months

pg 1056

X 2 = 20

Deciduous teeth dental formula:

****No premolars!

Adolescence adult

Permanent teeth enlarge and develop

Roots 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 years

May be absent!!

Adult dental formula:

2I, 1C, 2P, 3M

2I, 1C, 2P, 3M

Adolescence – Adult

X 2 = 32

pg 1056

Tooth troubles

Cavities (caries)

Demineralization of enamel by bacteria

In severe cases, erodes the dentin of tooth

Most severe cases erosion penetrates pulp cavity

Tooth Troubles

Tooth troubles1


Inflammation of the gingiva caused by plaque accumulation

Leads to…….


Infection of periodontal ligament leading to its destruction along with the bone around the teeth

Leads to toothlessness!

Tooth Troubles

Triangles of the neck

Triangles of the Neck

  • Neck subdivided into two triangles

  • Separated by the sternocleidomastoid muscle

  • Anterior triangle

  • Posterior triangle

Triangles of the neck posterior


Anterior - sternocleidomastoid

Posterior - trapezius

Inferior – clavicle


Nerves: accessory nerve, phrenic nerve, brachial plexus

Artery: Subclavian

Vein: External jugular

Triangles of the Neck: Posterior

pg 948

Triangles of the neck anterior


Anterior - midline

Posterior - sternocleidomastoid

Superior – inferior margin of the mandible


Glands: Submandibular

Muscles: Suprahyoid and infrahyoid muscles

Artery: Common carotid

Vein: Internal jugular, External jugular

Nerve: Accessory

Triangles of the Neck: Anterior

pg 954

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