Week 1 Theory - Oral Health Sciences

DENT2010

What are the functions of the tongue?

• Speech

• Mastication

• Swallowing

• Sensory

Explain the function of mastication of the tongue briefly.

It involves crushing food against the palate and moving food around the mouth.

What does the sensory function of the tongue involve?

• Pain

• Temperature

• Touch

• Gustation (tasting)

What are the 2 types of muscles the tongue has and explain the difference between them?

1. Intrinsic - change the shape of the tongue

2. Extrinsic - change the position of the tongue

Describe intrinsic muscles in the tongue.

• All origins & insertions are WITHIN the tongue.

• Attaches to peripheral & central connective tissue

What 3 planes are intrinsic muscles in the tongue known by?

• Vertical

• Transverse (across/horizontal)

• Longitudinal: superior & inferior

Describe extrinsic muscles in the tongue.

• All insertions are into the tongue

• All origins are OUTSIDE of the tongue

List the functions of the extrinsic muscles.

• Protrude

• Retract

• Depress

What are the origins of each of the extrinsic muscles?

What are the insertion locations of each of the extrinsic muscles?

• Genioglossus ⇒ inferior aspect of tongue & the hyoid

• Hyoglossus ⇒ lateral aspect of the posterior half of the tongue

• Styloglossus ⇒ Posterior bundles into the longitudinal intrinsic muscles on the lateral aspect of the tongue and the anterior bundles into the inferior aspect of the apex (tip)

• Palatoglossus ⇒ Posterolateral surface of the tongue

What are the actions of each of the extrinsic muscles?

What are the innervation of each of the extrinsic muscles?

List the different borders of the floor of the mouth.

• Inferior : Mylohyoid muscle

• Lateral : Medial surface of the mandible

• Anterior : Medial surface of the mandible

• Superior : Oral mucosa & tongue

• Posterior : Inferior aspect of the palatoglossal arch.

State the origin, insertion, action and innervation of the mylohyoid.

• Origin: mylohyoid line on the medial surface of the mandible.

• Insertion(s): mylohyoid raphe & body of the hyoid

• Action: Elevate the floor of mouth and/or depress the mandible

• Innervation: 5th Cranial Nerve, mandibular division (3rd branch) of the trigeminal nerve

List the contents of the floor of the mouth.

• Salivary glands & associated structures

• Nerves

• Blood vessels

• Lymphatics

List the salivary glands & associated structures that are located in the floor of the mouth.

• Submandibular salivary gland

• Sublingual salivary gland

• Wharton’s duct

• Various minor ducts

• Submandibular fossa

• Sublingual fossa

List the nerves of the floor of the mouth.

• Sensory: predominantly lingual nerve.

• Motor: Hypoglossal (CNXII), Mylohyoid branch (CNV3)

• Compex variations with many anastomoses possible.

The palate is the superior border of the oral cavity. Which 2 regions is the palate divided into?

Hard Palate & Soft Palate

Describe the anatomical features of the hard palate.

• Approximately anterior 2/3 of the palate

• Tissue firmly bound to periosteum

• Palatal rugae

• Minor salivary glands

List the functions of the hard palate.

• Separates nasal and oral cavities

• Speech

• Suckling & Mastication

Briefly describe the soft palate.

• Approximately, the posterior 1/3 of the palate *with the uvula hanging from the middle

• Flexible muscular flap extending from the posterior edge of the hard palate

• Attached to the lateral walls of the pharynx

What are the functions of the soft palate?

• Swallowing: When tensed, it assists the tongue by directing food into the pharynx without regurgitation into the nose.

• Breathing: can seal off the mouth to allow breathing whilst sucking and chewing to limit the danger of inhaling food.

• Coughing: seals off nasopharynx to allow the blowing of air through the mouth

Muscles of the soft palate are made up of what?

Made up of a fold of mucous membrane which encloses 5 pairs of muscles.

List the muscles of the soft palate and their functions.

• Tensor Palati - tenses the soft palate & possibly opens the auditory tube

• Levator Palati - elevates the soft palate

• Palatoglossus - pulls soft palate downwards as well as elevating the tongue.

• Palatopharyngeus - constricts the oropharynx & elevates the larynx.

• Muscularis Uvulae - elevates/retracts the uvula.

Describe the innervation of the palate.

SENSORY NERVES:

• These nerves are branches of Cranial Nerve V2 (maxillary division of the Trigeminal)

• Nasopalatine supplies the premaxilla

MOTOR NERVES:

• Soft Palate

• These are mostly from branches of CN X (Vagus)

Describe the blood supply of the palate.

• The greater palatine artery meets with nasopalatine artery to supply the hard palate and associated glands.

• The lesser palatine artery supplies the soft palate & its muscles

• Additional minor supplies are received from branches of the facial and external carotid arteries.

Describe the pharynx.

• A muscular tube lined with mucosa that is approximately 12cm long

• Attached to the cranial base

• Connects the outside worlds to the lungs and Gastrointestinal Tract

What 3 regions is the pharynx divided into?

• Nasopharynx - dorsal to the nasal cavities

• Oropharynx - dorsal to the mouth

• Laryngopharynx - dorsal to the larynx

Describe the nasopharynx.

• Continuous with the nasal cavity

• Continuous to humidify & warm air as it travels toward the lungs

• Mucous production

• Adenoids or pharyngeal tonsils

Describe the oropharynx.

• Separated from the oral cavity laterally by the palatine tonsils that sit between the palatopharyngeal fold (posterior tonsillar fauces) and the palatoglossal fold (anterior tonsillar fauces)

• Aids in swallowing

• Mucous production

Describe the laryngopharynx.

• Directly continuous with oesophagus

• Continuous with the vestibule of the larynx

• Ventral to inferior regions bordered by epiglottis

• Mucous production

Describe the pharynx.

• A muscular tube lined with mucosa that is approximately 12cm long

• Attached to the cranial base and connects the outside world to the lungs and G.I.T

What 3 overlapping muscle groups does the pharynx consist of?

• Superior constrictor

• Middle constrictor

• Inferior constrictor

What does the superior constrictor muscle group consist of?

• 2 bilateral muscles

• Origins include:

• Pterygomandibular raphe.

• Pterygoid hamulus.

• Mandible.

• Mucous membrane of the mouth.

• Lateral aspects of tongue.

• Inserting at the posterior median pharyngeal raphe

What does the middle constrictor muscle group consist of?

• Two bilateral fan shaped muscles.

• Origins include stylohyoid ligament & hyoid bone.

• Inserting at the posterior median pharyngeal raphe.

• Lies superficial to the superior constrictor.

What does the inferior constrictor muscle group consist of?

• Inferior and superficial to the middle constrictor.

• Origins are from the thyroid & cricoid cartilages of the larynx.

• Inserts into the posterior median pharyngeal raphe.

What is the origin, insertion and function of the right & left stylopharyngeal muscles?

• Origin – styloid process of the temporal bone

• Insertion – posterior & lateral pharyngeal walls

• Functions to elevate & widen the pharynx