The Head and Neck
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Transcript The Head and Neck
The Head and 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,
cranial plexus, phrenic nerve,
brachial plexus
Artery: Subclavian
Vein: External jugular
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: Carotid
Vein: Internal jugular, External
jugular
Nerve: Acccessory
Triangles of the Neck
Lingvalni trokuti su:
donji - trigonum linguale (Beclard) i
gornji - trigonum linguale Pirogoff
- dno oba trokuta je musculus hyoglossus;
- granice gornjeg su: intermedijarna tetiva digastrikusa i cornu maius ossis hyoidei
- granice donjeg su: intermedijarna tetiva digastrikusa i stražnji rub milohioidnog mišića
- lateralno od m. hyoglossus i površno kroz oba trokuta prolazi n.XII s venom pratilicom
- medijalno i ispod hyoglossus-a leži a. lingualis
Upper Respiratory Tract
Nasal Cavity
Nostril
Oral Cavity
Larynx
Pharynx
Nose
Only portion of the RT
that is externally visible
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
Nasal Cavity
Air enters here during
breathing
Passes through the
nares (nostrils)
Divided into R and L
by nasal septum
Continuous with the
nasopharynx through
the internal nares
Nasal Cavity
Boundries:
Roof – ethmoid bone (cribiform plate)
Floor – maxilla (palatine process)
palatine (horizontal plate)
Lateral walls – nasal bones, superior and middle nasal
conchae (ethmoid bone), inferior nasal conchae,
maxilla, palatine bone
Hard palate
Palatine bones and maxillary bone
Soft palate
Muscular posterior portion
Nasal Cavity
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)
Lining of the Nasal Cavity
Olfactory Mucosa
Roof of nasal cavity
Houses small receptors
Respiratory Mucosa
Pseudostratified ciliated
columnar epithelium
Goblet cells
Lamina propria
Mucous and serous cells
Venous plexus
Function is to filter and
warm inhaled air
Nasal Conchae
Project medially from each lateral wall
3 structures:
Superior
Middle of ethmoid bone
Inferior
Functions:
Filters air
Heats air
Moistens air
Reclaim heat and moisture during exhalation
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
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 (throat)
Lined with skeletal muscle
Divided into:
Nasopharynx
Oropharynx
Laryngopharynx
Regions of the Pharynx
Nasopharynx
Oropharynx
Laryngopharynx
Pg 584
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
Oropharynx
Location:
Postreior 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
Tonsils
Lymphoid organ
Swellings of the mucosa
lining the pharynx
Form ring around the
entrance to the pharynx
4 groups:
Palatine
Lingual
Pharyngeal
Tubal
Remove pathogens
MALT
Laryngopharynx
Location:
Lies posterior to larynx
Continuous with the
esophagus and larynx
Common
passageway for food
and air
Stratified squamous
epithelium
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
Composed of 9 cartilages connected by membranes and ligaments:
1 Thyroid
1 Cricoid
1 Epiglottis
2 Arytenoid
2 Corniculate
2 Cuneiform
Laryngeal Cartilages
Thyroid Cartilage
Large
Shield shaped
Formed by 2 plates
Composed of laryngeal
prominence
Adam’s Apple!!
Laryngeal Cartilages
Cricoid
Inferior to thyroid
cartilage
Forms a complete ring
Perched on top of the
trachea
Laryngeal Cartilages
Epiglottis
Composed of elastic
cartilage
Covered by mucosa
Projects upward from
anterior wall of
laryngeal inlet to level
of base of tongue
Vocal Cords
Located in the larynx
Mucosal folds formed by vocal
ligaments
Composed of elastic fibers
Run from arytenoid cartilages to
the thyroid cartilages
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)
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 TH
Increases metabolic rate
Calcitonin
Depresses excess levels of
Ca+ in blood
Thyroid Gland
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
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,
Mouth and Associated Organs
Mouth
Tongue
Salivary glands
Teeth
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
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 (pg 266-67)
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 muscle
Hard palate (anterior) provides surface for tongue to force
food against during chewing
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)
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:
Parotid
Submandibular
sublingual
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
Teeth – From Eruption to Edentate
Teeth lie in sockets (alveoli) in gumcovered margins in mandible and maxilla
Have 2 sets of teeth (dentitions)
Primary dentition / deciduous (milk) teeth
Permanent dentition (21 years; 32 teeth)
Incisors (8): rip, cut
Canines (4): tear and pierce
Premolars (8): grinding
Molars (12): grinding
Teeth
Function:
Ingestion and mechanical
breakdown of food
Periodontal ligaments
(collagen fibers) anchor
tooth in bony socket
Gomphosis - form of
immovable articulation; a
peglike part fits into a
cavity
Continous with gingiva
(gum)
Teeth
Regions:
Crown
Covered with enamel
Area above gingiva
Neck (gumline)
Root
Area below neck in alveolus
Pulp cavity
Center of tooth
Loose CT with vessels and
nerves
Supplies nutrients to hard
tissues
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
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 at Birth
Number of erupted
teeth = 0
Jaws covered by
gingiva (gums)
Lots of drooling!!!
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)
Deciduous teeth dental formula:
2I, 1C, 2M
2I, 1C, 2M
X 2 = 20
****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
X 2 = 32
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
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……………