The Head and Neck. Upper Respiratory Tract Nostril Nasal Cavity Oral Cavity Pharynx pg 944.
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Transcript of The Head and Neck. Upper Respiratory Tract Nostril Nasal Cavity Oral Cavity Pharynx pg 944.
The Head and Neck
Upper Respiratory Tract
NostrilNasal CavityOral CavityPharynx
pg 944
Nasal Cavity
Nose is the only portion of the RT that is externally visible CT, bone, hyaline cartilage
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 973
Nasal Cavity
Air enters here during breathingPasses through the external nares (nostrils)
Divided into R and L by nasal septumContinuous with the nasopharynx through
the internal nares (choanae)
pg 944
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 palatePalatine bones and maxillary bone
Soft palateSkeletal muscle posterior portionEnd in uvula
Nasal CavityVestibule
Superior to nostrilsSkin 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
VibrissaeNose hairsFilter large particles (insects)
pg 965
Lining of the Nasal CavityOlfactory Mucosa
Roof of nasal cavity Houses smell 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 Highly innervated
Sneeze!
www.mc.vanderbilt.edu/.../Respiratory03.htm
Nasal Conchae
Project medially from each lateral wall3 structures:
Superior of ethmoid boneMiddle of ethmoid boneInferior
Functions:Create turbulence to increase:
Filters air Heats airMoistens airReclaim heat and moisture during exhalation
pg 973
Paranasal Sinuses
Air filled cavities that surround the nasal cavityLined by mucosaPerform same function as nasal cavity and
lightens skullLocated in Frontal, Ethmoid, Sphenoid, Maxilla
bones
pg 970
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 muscleDivided into:
NasopharynxOropharynx Laryngopharynx
pg 944
Tonsils
Lymphoid organMALT
Swellings of the mucosa lining the pharynxForm ring around the entrance to the pharynx4 groups:
PalatineLingualPharyngealTubal
Remove pathogens
pg 944
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
pg 944
Oropharynx
Location: Posterior to the oral cavity Extends inferiorly from level of the soft palate to level of the
epiglottisSwallowed food and inhaled air pass through hereStratified squamous epitheliumContain:
Palatine tonsils Lingual tonsils
pg 944
Laryngopharynx
Location:Lies posterior to larynxContinuous with the esophagus and larynx
Common passageway for food and airFood – esophagusAir - larynx
Stratified squamous epithelium
pg 944
Larynx
“Voice box”Extends from C4 to C6
Attachments:Hyoid bone superiorlyContinuous with trachea inferiorly
Functions:VocalizationProvides open airwaySwitches to route air and food into proper channels
Innervation: VagusSuperior part = stratified squamous epitheliumBelow vocal cords= ciliated pseudostratified columnar
pg 949
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 952-3
Laryngeal Cartilages
Thyroid CartilageLargeShield shapedFormed by 2 platesContains laryngeal
prominenceAdam’s Apple!!
pg 950
Laryngeal Cartilages
Cricoid Inferior to thyroid
cartilageForms a complete ringDirectly superior to
trachea
pg 952
Laryngeal Cartilages pg 951
Vocal Cords
Located in the larynxMucosal 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)
pg 960
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
pg 917
Thyroid Gland
Internally, composed of folliclesFollicular cells
TH
Parafollicular cellsCalcitonin
Blood supplySuperior thyroid arteries
Branches of external carotids
Inferior thyroid arteriesBranches of subclavians
Parathyroid Gland
Two pairsLocated on the deep surface of the lateral
lobes of the thyroid glandProduce parathyroid hormone
Increases blood calcium levels
pg 917
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, larynxComposed of:
Body 2 pairs of horns
Functions: Moveable base for tongue Points of attachment for larynx and neck muscles
Sternohyoid, thyrohyoid,
pg 755
Oral Cavity and Associated Organs
MouthTongueTeeth
External Salivary glands
pg 944
Mouth - Oral Cavity
Food enters alimentary canal through hereMucosa-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
pg 993
Mouth
Lips (labia) and CheeksKeep food inside mouth during chewingComposed of skeletal muscle surrounded by skinLips formed by orbicularis oris muscleCheeks; 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 mouthSoft palate (posterior) rises to close off nasopharynx
during swallowing; made of skeletal muscleHard 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)
pg 989
Moving Bolus
Swallowing voluntarily initiated (pharynx)Peristalsis = propulsion
InvoluntaryAlternate waves of contraction and relaxation of muscles
in organ walls (e.g. esophagus)Squeezes food from one organ to nextSome 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:
ParotidSubmandibularsublingual
pg 820pg 997
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 998
Teeth – From Eruption to EdentateFunction:
Ingestion and mechanical breakdown of food
Have 2 sets of teeth (dentitions)Primary dentition /
deciduous (milk) teethPermanent dentition
Incisors: rip, cutCanines: tear and piercePremolars: grindingMolars: grinding
pg 1008
Teeth
Gomphosis Synarthrosis Peg in socket with ligament
The sockets (alveoli) are in gum-covered margins of mandible and maxilla
Periodontal ligaments (collagen fibers) anchor tooth in bony socket Continous with gingiva (gum)
Teeth
Pulp cavity Center of tooth Loose CT with vessels and nerves Supplies nutrients to hard tissues
Regions: Crown
Covered with enamelArea projecting beyond gingiva
Neck (gumline) Root
Area beyond neck in alveolus
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 SubstancesEnamel
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)
2I, 1C, 2M 2I, 1C, 2M
X 2 = 20
****No premolars!
Deciduous teeth dental formula:
Adolescence – AdultPermanent 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 yearsMay be absent!!
Adult dental formula:
2I, 1C, 2P, 3M2I, 1C, 2P, 3M
X 2 = 32
pg 1008
Tooth Troubles
Cavities (caries)Demineralization of
enamel by bacteria In severe cases, erodes
the dentin of toothMost severe cases
erosion penetrates pulp cavity
Tooth Troubles
Gingivitis Inflammation of the gingiva caused
by plaque accumulationLeads to…….
Periodontitis Infection of periodontal ligament
leading to its destruction along with the bone around the teeth
Leads to……………Toothlessness!
Triangles of the Neck
Neck subdivided into two trianglesSeparated by the sternocleidomastoid
muscleAnterior trianglePosterior triangle
Triangles of the Neck: Posterior
Boundries:Anterior - sternocleidomastoidPosterior - trapezius Inferior – clavicle
Contents:Nerves: accessory nerve,
phrenic nerve, brachial plexusArtery: SubclavianVein: External jugular
pg 905
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 762