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

Nose

Nostril

Nasal Cavity

Oral Cavity

Pharynx

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)

Nose

pg 1023


Vestibule

Superior to nostrils

Skin lined with:

Sebaceous glands

Greasy secretion

Collect dirt

Lubricate

Kill bacteria

Sweat glands

Acidic

Slows growth of bacteria

Hair follicles

Trap small particles of dirt

Vibrissae

Nose hairs

Filter large particles (insects)

Vestibule

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

Sneeze!

Olfactory Mucosa

Roof of nasal cavity

Houses smell receptors

No goblet cells

Cilia modified for olfaction

Lining of the Nasal Cavity

www.mc.vanderbilt.edu/.../Respiratory03.htm


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


Pharynx

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:

Nasopharynx

Oropharynx

Laryngopharynx

Pharynx

pg 992


Tonsils

Lymphoid organ

MALT

Swellings of the mucosa lining the pharynx

Form ring around the entrance to the pharynx

4 groups:

Palatine

Lingual

Pharyngeal

Tubal

Remove pathogens

Tonsils

pg 992


Nasopharynx

Location:

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

Giggling!

Ciliated pseudostratified epithelium

Contain:

Pharyngeal tonsils (adenoids)

Tubal tonsils

Nasopharynx

pg 992


Oropharynx

Location:

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

Contain:

Palatine tonsils

Lingual tonsils

Oropharynx

pg 992


Laryngopharynx

Location:

Lies posterior to larynx

Continuous with the esophagus and larynx

Common passageway for food and air

Food – esophagus

Air - larynx

Stratified squamous epithelium

Laryngopharynx

pg 992


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

Larynx

pg 1001


Larynx1

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

Larynx

pg 1001

pg 1000


Laryngeal cartilages

Thyroid Cartilage

Large

Shield shaped

Formed by 2 plates

Contains laryngeal prominence

Adam’s Apple!!

Laryngeal Cartilages

pg 998


Laryngeal cartilages1

Cricoid

Inferior to thyroid cartilage

Forms a complete ring

Directly superior to trachea

Laryngeal Cartilages

pg 998


Laryngeal cartilages2

Epiglottis

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

Location:

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

Calcitonin

Depresses excess levels of Ca+ in blood

Thyroid Gland

pg 966


Thyroid gland1

Internally, composed of follicles

Follicular cells

TH

Parafollicular cells

Calcitonin

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

Location:

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:

Body

2 pairs of horns

Functions:

Moveable base for tongue

Points of attachment for larynx and neck muscles

Sternohyoid, thyrohyoid,

Hyoid Bone

pg 803


Oral cavity and associated organs

Mouth

Tongue

Teeth

External Salivary glands

Oral Cavity and Associated Organs

pg 992


Mouth oral cavity

Food enters alimentary canal through here

Mucosa-lined

Thick stratified squamous epithelium, with keratinization in some areas

Boundaries:

Lips anteriorly

Cheeks laterally

Palate superiorly

Tongue inferiorly

Oropharynx posteriorly

Mouth divided into 2 parts:

Vestibule

Oral cavity proper

Mouth - Oral Cavity

pg 1041


Mouth

Mouth

  • 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


Tongue

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


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

www.answers.com


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 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

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

Teeth – From Eruption to Edentate

pg 1056


Teeth

Gomphosis

Synarthrosis

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


Teeth substances

Enamel

Made of calcium salts

Avascular, acellular

Not renewed or replaced

HARDEST substance in body!!!!

Dentin

Underlines enamel

Forms bulk of tooth

Made of minerals and collagen

Maintained during life

Harder than bone

Cementum

Calcified external surface

Attaches tooth to periodontal ligament

Teeth Substances


Teeth1

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

Teeth


Teeth2

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

Teeth


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

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!

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

Boundries:

Anterior - sternocleidomastoid

Posterior - trapezius

Inferior – clavicle

Contents:

Nerves: accessory nerve, phrenic nerve, brachial plexus

Artery: Subclavian

Vein: External jugular

Triangles of the Neck: Posterior

pg 948


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

Triangles of the Neck: Anterior

pg 954


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