oral cavity and tongue

bios1163

Describe the structure and function(s) of the lips

• Mobile muscle covered by skin and lined by mucous membrane

• Labial glands open into buccal cavity

• Functions: 

• Close against possible exit of food 

• Mediate facial expression 

• Add volume to oral cavity proper

• Act as a sphincter to produce sounds eg. “p” via the action of the facial muscles

• Form a ‘lip reed’ to affect expired air (brass musicians)

Describe the boundaries of the oral cavity proper and the vestibule

• Oral cavity proper

• Anterior boundary: teeth

• Lateral boundary: teeth (in alveolar arches)

• Posteriorly: palatoglossal arch (anterior faucial pillar)

• Superior: hard and soft palates

• Inferior: tongue 

• Uvula 

• Oral vestibule

• Area between the teeth rows and lips/cheek

identify functions of the oral cavity 

• Ingestion

• Mastication

• Digestion

• Pressurise air (eg. whistling)

• Vocal tract

• Obstruct/ partially obstruct sound

• Modify resonance of sound by changing shape

describe the function of the tongue

• Mastication

• Swallowing

• Taste

• Articulation 

Describe the structure and function(s) of the cheeks

• Mobile inner component: buccinator

• Change the volume of the oral cavity 

• Keeps food (or air) in the oral cavity proper 

Describe the structure and function(s) of the teeth

• Structure

• Enamel 96% mineral

• Dentin 66% mineral forms throughout life

• Cementum 50% mineral

Role of the teeth 

• Teeth provide the mechanism for mastication as well as the articulatory surfaces for several speech sounds

• No evidence that abnormal teeth arrangement → articular disorders (but affects mastication)

• Tongue can adjust somewhat for teeth defects in speech

identify and describe the intrinsic muscles of the tongue 

Intrinsic muscle	Function
Superior longitudinal	Retracts tongue Turns tip up Forms a trough
Inferior longitudinal	Retracts tongue  Turns tip down
Transverse	Narrows and elongates the tongue
Vertical	Flatten and depresses the tongue

identify and describe the extrinsic muscles of the tongue 

Extrinsic muscle	Function
Genioglossus	Lowers centre of tongue (all) Retract (anterior fibres) Protrude (posterior fibres)
Styloglossus	Draws back of tongue back and up
Palatoglossus	Elevates posterior tongue Depresses soft palate Narrows the fauces (anterior faucial pillar)
Hyoglossus	Pulls sides of tongue down

Describe the structure and function(s) of the salivary glands.

• Salivary glands

• Initiate digestion

• Soften bolus

• Frictionless movement for speech 

• Needs to secrete saliva which is rich in enzymes for the breakdown of food

• Parotid gland opens into the buccal cavity above the upper second molar tooth (via the parotid duct)

• Submandibular opens in the floor of mouth 

• Sublingual opens under the tongue

• Exocrine glands have ducts

study the development, structure and eruption patterns of the teeth

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study the nerve supply of the oral cavity

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