Transcript Slide 1
The Head and Neck Upper Respiratory Tract Pg 583 The Nose • Only external part of respiratory tract • Made of nasal bones, connective tissue and hyaline cartilage • External Nares = Nostrils: – openings into nasal cavity • Internal Nares = Choanae: – openings between nasal cavity and nasopharynx Entrance to the Nasal Cavity • Vestibule –space just inside external nares • Skin lining contains: – Sebaceous glands greasy secretion collect dirt, lubricate, kill bacteria – Sweat glands -acidic, slows growth of bacteria – Hair follicles –trap smaller particles of dirt and dust • Vibrissae – nose hairs filtering larger particles from air Nasal Cavity • Part of respiratory passage • Boundaries – Roof = ethmoid bone (cribiform plate) – Floor = hard palate & soft palate • Hard palate = maxilla (palatine process) + palatine (horizontal plate) • Soft palate = skeletal muscle ending in uvula – Lateral walls = nasal bones, superior+ middle nasal conchae (ethmoid bone), inferior nasal conchae, maxilla, palatine bone – Nasal Septum = divides cavity into 2 • Vomer & Perpendicular Plate of Ethmoid • Cartilage Nasal Cavity Pg 584 Nasal Cavity • Functions – Airway of respiratory tract – Moisten and Warm air – Filter air – Resonating chamber for speech – Houses olfactory receptors Nasal Cavity (continued) • Respiratory Mucosa–lines cavity walls, septum – Ciliated psuedostratified columnar epithelium w/lamina propria • Mucous cells + serous cells – Highly vascularized • Moistens + warms inhaled air – Highly innervated • Cause sneeze reflex • Olfactory Mucosa – on roof of nasal cavity, contains the olfactory (smell) receptors Nasal Conchae • Project medially from each lateral wall of nasal cavity • Superior, Middle (ethmoid) • Inferior nasal conchae • Covered with Mucosa • Functions – Increase surface area – Create turbulance – Reclaim heat from exhaled air Pg 584 Paranasal Sinuses • • • • • Air-filled sacs surrounding nasal cavity Extensions of nasal cavity, continuous with it Same respiratory mucosal lining In Frontal, Ethmoid, Sphenoid, Maxillae bones Function: Warm + Filter air, Lightens skull Pg 16 Mouth = Oral Cavity • Opening of alimentary canal • Lined with mucosa • Thick, stratified squamous epithelium (slightly keratinized in some parts) • Boundaries – – – – – Pg 617 Anterior = lips Lateral = cheeks Posterior = oropharynx Superior = palate Inferior = tongue Some Muscles of Face • Lips (labia) + Cheeks: Keep food in mouth during chewing • Lips: Orbicularis oris • Cheeks: Muscles of Mastication – – – – – Temporalis Masseter Buccinator Digastric Pterygoids Muscles of Mastication Name Origin Insertion Action Innervation Pterygoids (med & lat) Pterygoid plate (sphenoid), Maxilla, Palatine bone Mandible Elevate & Protract Mandible Trigeminal N. (branch V3) Digastric Mandible, Mastoid process (temporal) Hyoid bone (indirectly) Elevate hyoid, Depress mandible Trigeminal N. (branch V3) Masseter Zygomatic arch and bone Mandible (angle and ramus) Elevates mandible Trigeminal N. (branch V3) Temporalis Temporal bone Coronoid process of mandible (indirectly) Elevates & retracts mandible Trigeminal N. (branch V3) Palate • Hard palate (anterior 2/3) – Made of bone – Covered with mucosa – Tongue pushes food against it during chewing • Soft palate (posterior 1/3) – Made of skeletal muscle – Covered by mucosa – Ends in the uvula – Closes nasopharynx during swallowing Tongue • Functions – – – – – bitter sour Grips and moves food between teeth during chewing Mixes food with saliva = BOLUS Moves bolus down pharynx Speech production Houses taste buds (= gustation) salty • Creates floor of mouth • Attachments: hyoid, mandible, styloid process, soft palate sweet • Made of Skeletal muscle w/CT septum – Intrinsic muscles – Extrinsic muscles • Innervation – Motor = Hypoglossal (CN XII) – Sensory = Mandibular (CN V3), Facial (CN VII), Glossopharyngeal (CN IX) Pg 618 Salivary Glands • Exocrine, tubuloalveolar glands • Produce Saliva – H2O, Ions, Mucus, Enzymes • Internal salivary glands are small – In mucosa of tongue, lips, palate, cheeks – Keep areas wet • External salivary glands are large, have ducts – External to mouth – Provide saliva when necessary or anticipated – 2 Submandibular, 2 Sublingual, 2 Parotid glands Salivary Glands • • • • • • • Pg 618 Moisten mouth, wet food Dissolve food to taste Bind food together Begin to break down starch Neutralize mouth acid Kill harmful microorganisms Promote beneficial bacteria Tiny Tabitha’s Teeth The story of teeth from eruption to edentate Tiny Tabitha: Age 4 days • Number of Erupted Teeth = 0 • Ultimate Goal = 32 Teeth – – – – Incisors (8): rip, cut Canines (4): tear and pierce Premolars (8): grinding Molars (12): grinding • Estimated Time of Completion = 15-25 years • Currently jaws covered by gingiva (gum): is oral mucosa = lots of drooling Tabitha’s First Tooth • Deciduous (Milk) = 20 – – – – 8 Incisors = 6-10 months 4 Canines = 16-20 months 4 1st Molars = 12-16 months 4 2nd Molars = 20-24 months • Dental Formula: describes number, kind & position of teeth in ½ of the mouth canines Incisors 2:1:0:2 2:1:0:2 premolars molars X 2 = 20 Tabitha’s Teeth • Function: Ingestion and mechanical breakdown of food • Alveoli: sockets in mandible and maxilla teeth sit in • Periodontal Ligament: collagen fibers anchor tooth in bony socket – Gomphosis • Cementum: calcified connective tissue attaching tooth to periodontal ligament Pg 620 Gross Anatomy of a Tooth Pg 620 • Crown = area above gingiva • Neck = (gumline) where crown and root meet • Root = area below neck in alveolus Tabitha’s Teeth Begin to Tumble • Around 7 years of age the periodontal ligaments & roots of deciduous teeth are eroded = teeth fall out • Permanent teeth begin to erupt between 7-13 years • 3rd Molars (Wisdom Teeth) may not erupt until 17-25 years • End Result: Adult Dental Formula premolars 2:1:2:3 2:1:2:3 X 2 = 32 Tabitha’s Tooth Troubles • College --> too much junkfood = CAVITIES (caries) • Bacteria erodes through the outer enamel covering of tooth – – – – Avascular, Acellular Mostly calcium salts Not renewed or replaced Hardest substance in body • In severe cases it erodes the deeper dentin of tooth – – – – Made of minerals & collagen Is maintained during life Harder than bone Bulk of tooth Pg 620 Tabitha’s Tooth Trauma! • Most severe cases erosion penetrates pulp cavity – Center of tooth – Pulp = loose CT w/ vessels & nerves – Supplies nutrients to hard tissues • Root canal: part of pulp cavity in root • Apical Foramen: opening of pulp cavity into root canal • Artery: Sup/Inf Alveolar aa, branches of Ext Carotid a • Innervation: – Maxilla = Superior Alveolar Nerves – Mandible = Inferior Alveolar Nerves Pg 620 Tabitha’s Teeth: the later years • Tabitha graduates college, begins to take better care of her teeth (i.e. consistent brushing, flossing & dental visits), and leads a normal happy tooth-filled life UNTIL……… • GINGIVITIS…..(inflammation of the gingiva caused by plaque accumulation) leads to….. Toodaloo Tabitha’s Teeth • PERIODONTITIS – Infection of periodontal ligament leading to its destruction and that of the bone around teeth – Leading to…….. • TOOTHLESSNESS!!! Pharynx = “Throat” • Connects nasal cavity & mouth to esophagus & larynx • Runs from skull to C6 • Carries food and air • Lined with skeletal muscle • Divided into 3 regions – Nasopharynx – Oropharynx – Laryngopharynx Pg 617 Tonsils • Swellings of mucosal lining of pharynx • Simple lymph organs – MALT: mucosa-associated lymphoid tissue • Form ring around opening of pharynx • 4 groups Pg 570 – – – – Palatine (pair) Lingual Pharyngeal Tubal (pair) Regions of the Pharynx Nasopharynx Oropharynx Laryngopharynx Pg 584 Nasopharynx: Only carries air • Ciliated pseudostratified epithelium • Location – Posterior to Nasal Cavity – Inferior to Sphenoid bone – Superior to Soft Palate • Closed off during swallowing by soft palate & uvula • Pharyngeal tonsils (adenoids) • Tubal tonsils Oropharynx: Carries Food & Air • Thick, protruding stratified squamosal epithelium due to great friction • Location – Posterior to Oral Cavity – Runs from Soft Palate to Epiglottis • Palatine tonsils • Lingual tonsils Laryngopharynx: Carries Food & Air • Stratified squamosal epithelium • Location – Posterior to Larynx • Continuous with esophagus (digestive system) • Continuous with larynx (respiratory system) Moving the Bolus • Swallowing – Voluntarily initiated (pharynx) – Suprahyoid, Infrahyoid, Pharyngeal constrictors • Peristalsis = propulsion Pg 611 – Involuntary – Alternate waves of contraction and relaxation of muscles in organ walls (e.g. esophagus) – Squeezes food from one organ to next – Some mixing Hyoid Bone • Only bone not directly articulated with other bones • Attaches via ligaments to temporal bone, larynx • Components – Body – Pair of Greater Horns – Pair of Lesser Horns • Functions Pg 163 – Moveable base for tongue – Attachment for sternohyoid, thyrohyoid – Superior attachment for larynx Larynx = “voicebox” • Location: C4-6 – Low in neck for speech • Attachments – Superiorly = hyoid bone – Inferiorly = trachea • Innervation = vagus • Functions Pg 570 – Voice production – Airway – Routes food/air Laryngeal Cartilages • 9 Cartilages connected by ligaments & membranes – – – – – – 1 Epiglottis 1 Thyroid 1 Cricoid 2 Arytenoid 2 Corniculate 2 Cuneiform • Superior part = stratified squamosal epithelium • Below vocal cords= ciliated pseudostratified columnar Laryngeal Cartilages • Epiglottis – Elastic cartilage; Mucosa covering – Projects upward from anterior wall of laryngeal inlet to level of base of tongue • Thyroid Cartilage – Large, shield shaped, made of 2 plates – Laryngeal prominence • Cricoid Cartilage – Shaped like signet ring – Between thyroid cartilage and trachea Laryngeal Cartilages Pg 587 Vocal Cords • • • • • Located in larynx Vocal ligaments run from arytenoid and thyroid cartilages Elastic fibers covered by mucosa True vocal cords = Mucosal folds Exhaled air passes over them causing vibration – Force of air = volume – Length & tension of folds = pitch • “False” vocal cords = Vestibular folds – lie superior to true pair, no role in voice production Pg 588 The Vocal Cords Thyroid cartilage True Vocal Folds Aretynoid cartilage False Vocal Folds True Vocal Folds Thyroid Gland • Location: – Along trachea, just inferior to larynx – “Butterfly” shape Pg 718 • Endocrine Gland – Thyroid hormone (TH): increases basal metabolic rate – Calcitonin: depresses excessive levels of Ca2+ in blood • Blood Supply: – Superior thyroid arteries (branches of ext. carotids) – Inferior thyroid arteries (branches of subclavians) The Parathyroid Glands • Usually 4 • Posterior thyroid • Parathyroid hormone, parathormone or PTH – Increases Ca++ levels in blood Triangles of the Neck Each half of the neck can be divided into 2 triangles: 1 Anterior and 1 Posterior Anterior Muscles of the Neck Name Origin Insertion Action Sternocleido- Manubrium, Mastoid proc. Flex or rotate mastoid clavicle (temporal bone), head nuchal line (occipital bone) Sternohyoid Innervation Accessory n. Manubrium, Hyoid bone clavicle Depress C1-C3 spinal larynx & hyoid nerves Sternothyroid Manubrium Thyroid cartilage of larynx Moves thyroid C1-C3 spinal cartilage, nerves larynx, hyoid inferiorly Anterior Triangle of the Neck • Boundaries – Superior = Inferior margin of Mandible – Anterior = Midline of Neck – Posterior = Sternocleidomastoid muscle • Contents – – – – – Muscles: Suprahyoid, Infrahyoid Artery: Carotid Vein: Internal Jugular, External Jugular Nerve: Accessory Glands: Submandibular Posterior Triangle of the Neck • Boundaries – Anterior = Sternocleidomastoid muscle – Posterior = Trapezius muscle – Inferior = Clavicle • Contents – Nerves: Phrenic, Accessory, Cervical Plexus,Brachial Plexus – Artery: Subclavian – Vein: External Jugular Triangles of the Neck pg 739