Mastication and Deglution

Mastication and Deglution

1. Oral Cavity

   • Bones: maxilla, mandible, palatine and teeth
     • Temporomandibular joint
       • modified hinge type of synovial joint
         • Articular surfaces: mandibular fossa and tubercle of temporal bone
           • Intrinsic ligaments: lateral ligament (strengthens the joint laterally) and fibrous capsule
           • Extrinsic ligaments: stylomandibular ligament and the sphenomandibular ligament
       • Movements: elevation, depression, protrusion, retrusion, lateral movements
   • It has two parts: vestible and proper cavity
     • Vestible: space between the teeth and lips-cheeks
       • oral fissure
         • Size determined by perioral muscles: orbicularis oris and buccinator, risorius (dilators)
     • Proper cavity: space between dental arches, roof: palate
   • Lips
     • muscular folds: orbicularis oris and superior and inferior labial muscles
       • externally: skin / internally: mucous membrane.
         • Irrigation: superior and inferior labial arteries (branch: facial arteries)
     • Gingivae
       • fibrous tissue with mucous membrane.
         • Proper: attached to alveolar proccess
         • Bucal: adyacent to lips and cheeks
       • Teeth (32)
         • incisors, canines, premolars, molars
           • deciduous
           • permanent
           • Three parts: root, neck, crown
             • Irrigation: superior and inferior alveolar arteries (branch of maxillary artery)
               • Innervation: CN V2 and CN V3
   • Palate: separates from the nasopharynx
     • Hard
       • bones: 2/3 palatine process of the maxilla and 1/3 of palatine bones
     • Soft
       • movable posterior third, no bones, palatine aponeurosis
         • Has the uvula
           • Palatoglossal arch
             • Fauces: laterally surrounded by the arches
               • space between: oral cavity and the pharynx.
               • Isthmus: connection between cavity proper and oropharynx.
           • Palatopharyngeal arch
       • Muscles of soft palate
         • Tensor veli palatini
           • pterygoid nerve (CN V3)
         • Levator veli palatini
           • pterygoid nerve (CN V3)
         • Palatoglossus
           • Pharyngeal branch (CN X)
             • Elevates posterior part of tongue
         • Palatopharyngeus
           • Pharyngeal branch (CN X)
             • Tenses soft palate
         • Musculus uvulae
           • Pharyngeal branch (CN X)
             • Shortens uvula
     • Tongue
       • Immobile posterior part between the mandible and hyoid
       • Body: anterior2/3 between root and apex.
       • Apex: anterior end
       • Dorsum
         • Papillae
           • Vallate
             • anterior to terminal sulcus (V- shaped row) Have taste buds
           • Foliate
             • laterally in the tongue
           • Filiform
             • gray due to keratin
           • Fungiform
             • most numerous in apex
       • Muscles
         • Extrinsic
           • Genioglossus
             • unilateral: deviates tongue to contralateral side. / Bilateral: depresses tongue
           • Hyoglossus
             • Depresses and retrudes tongue
           • Styloglossus
             • Retrudes tongue and curls its sides
           • Palatoglossus
             • Elevates posterior tongue or depresses soft palate
         • Intrinscic
           • Superior longitudinal
             • Curls tongue upward, elevates apex
           • Inferior longitudinal
             • Curls tongue downward, depresses apex
           • Transverse
             • Protrudes tongue
           • Vertical
             • Flattens tongue

2. Mastication muscles

   • Temporalis
     • Elevates mandible, closing jaws
   • Masseter
     • Elevates mandible, closing jaws
   • Lateral pterygoid
     • bilaterally, protracts mandible / unilaterally swings jaw to contralateral side
   • Medial pterygoid
     • elevate mandible; contributes to protrusion
   • Suprahyoid muscles
     • Digastric
     • Stylohyoid
     • Mylohyoid
     • Geniohyoid
     • ACTION: Depresses mandible against resistance
     • Infrahyoid muscles
       • Omohyoid
       • Sternohyoid
       • Sternothyroid
       • Thyrohyoid
       • Fixes or depresses hyoid bone

3. Salivary glands

   • Parotid
     • Largest, has the parotid sheath
       • Parotid duct (Stensen): pierces the buccinator, and enters the oral cavity through a small orifice on the 2nd maxillary molar tooth.
         • CN IX- secretory fibers through the otic ganglion = produces a thin, watery saliva.
         • Sympathetic: from the carotid nerve plexus
   • Submandibular
     • lie along the body of the mandible
       • submandibular duct: 5cm sublingual caruncula
         • submental arteries
   • Sublingual
     • lies in the floor of the mouth
       • sublingual and submental arteries

4. Deglution: transportes solids and liquids such as saliva from oral cavity to esophagus

   • Alteration: Disfagia
   • Delution center in the medulla oblongata
   • Deglution reflex: on 3 parts • Palatoglossus arch • tongue dorsum • Posterior pharynx wall
     • The stages of deglutition can be divided into 3 stages: Oral Phase / Pharyngeal Phase / Esophageal Phase
       • Oral Phase • initiates the swallowing reflex, the mylohyoid, genihyoid and digastric muscles elevate the tongue towards the hard palate
         • The base of the tongue presses against the soft palate and the posterior wall of the pharynx by means of the stifle and hypoglossal muscles
           • rises before the bolus reaches the pharyngeal recesses and prevents nasopharyngeal regurgitation
       • Pharyngeal phase • The palatopharyngeal folds approach, form a slit = the food passes to the posterior pharynx.
         • Interruption of breathing occurs physiologically. Swallowing apnea • The epiglottis tilts down, protects the airway • Hyoid is elevated
           • • The food bolus enters the pharynx, the cricopharyngeus muscle relaxes and allows the passage of food into the esophagus.
             • This phase lasts 1.5 seconds
       • Esophageal phase • It is involuntary: muscular contractions that drive the bolus from the cricopharyngeal sphincter to the stomach. • This stage lasts from 8 to 10 seconds.
         • Lower esophageal sphincter, a muscular ring at the end of the esophagus avoids reflux
           • lower esophageal sphincter, a ring of muscle at the end of the esophagus where it joins the stomach
           • FAILS: Gastroesophageal reflux disease
             • Barrett's Esophagus
               • replacement of the normal stratified squamous epithelium lining of the esophagus by simple columnar epithelium

5. Esophagus (25cm)

6. Pauly Carrera Camacho A01364154

   • *Moore K.L. Anatomía Humana con Orientación Clínica Editorial Médica Panamericana. Barcelona (1993)
     • Guyton, A.C.& Hall, J.E. (1996). "Tratado de Fisiología médica". 9ª Edición. Interamericana-McGraw-Hill. Madrid
       • SCHWARTZ. Principio de Cirugía. Malrotación congénita.6a ed. México: Editorial McGRAW-HILL INTERAMERICANA

Images and files in the map