Oral Cavity and Salivary Glands Flashcards
MOUTH
The oral fissure, between the lips, is the entry to the mouth. The oral cavity is bounded laterally by the cheeks and extends posteriorly to the oropharyngeal isthmus.
Regions of oral cavity
- Vestibule – space between the lips/cheeks and the upper and lower alveolar ridges/teeth
- Oral cavity proper –area “medial” to the alveolar ridge/teeth
Buccinator
- Muscle of the cheek (muscle of facial expression)
- Prevents food from accumulating in the vestibule by compressing the check against the teeth and gums. Together with the tongue, it keeps food between the teeth during mastication
Parotid Papilla
The parotid duct pierces the buccinator to drain into the vestibule opposite the maxillary (upper jaw) second molar tooth. The site of drainage is called the Parotid papilla.
Lingual frenulum
A midline fold of mucosa going from the floor of the mouth to the inferior surface of the tongue near its base
Sublingual papilla (caruncle)
Opening of the submandibular salivary duct on each side of the lingual frenulum
Sublingual folds
Mucosa overlying the sublingual glands and submandibular ducts; extends posterolaterally from the sublingual papilla
Muscles of the floor of the Mouth
- Mylohoid
* Geniohyoid
Submandibular gland
It has a superfcicial part in the digastric triangle and a smaller deep portion within the oral cavity.
The submandibular duct passes anteriorly beneath the mucosa of the oral cavity to empty into the sublingual papilla, just lateral tot he frenulum of the tongue
Sublingual gland
Rests upon the mylohyoid muscle and numerous small excretory ducts drain onto the summit of the sublingual fold
Parasympathetic Innervation of the Head
Preganglionic —> Ganglion –> Postganglionic
• CN III –> Ciliary –> CN V1 branch
• CN VII –> Pterygopalatine –> CN V2 branch
• CN VII –> Submandibular –> CN V3 branch
• CN IX –> Otic –> CN V3 branch
Parasympathetic (secretomotor) Innervation of Submandibular and Sublingual Glands
- Preganglionic parasympathetic neurons travel in the Chorda Tympani nerve (branch of CN VII).
- These neurons join the Lingual nerve (branch of V3) to reach the submandibular ganglion.
- Preganglionic fibres synapse in the submandibular ganglion.
- Postganglionic travel to the glands in the Lingual nerve
Sympathetic (vasomotor) Innervation of Submandibular and Sublingual Glands
- Sympathetic neurons synapse in the Superior Cervical ganglion
- Sympathetic neuron then travel on branches of the External carotid artery: Lingual and Facial arteries
Minor Salivary Glands
- Labial
- Buccal
- Molar
- Palatine
- Lingual
Parasympathetic Innervation of Salivary glands in Oral Cavity - ( Superior Half)
Glands in the Superior half of the oral cavity receive their parasympathetic innervation from nerves that synapse in the Pterygopalatine ganglion
Parasympathetic Innervation of Salivary glands in Oral Cavity - ( Inferior Half)
Glands in the Inferior half of the oral cavity receive their parasympathetic innervation from nerves that synapse in the Submandibular ganglion
Summary of Parasympathetic Innervation of Salivary glands
Preganglionic —> Ganglion –> Postganglionic
• CN VII (Greater petrosal; nerve of pterygoid canal) –> Pterygopalatine –> CN V2 branch –> Minor salivary glands of superior oral cavity
- CN VII (chorda tympani, lingual nerve of V3) –> Submandibular –> CN V3 branch –> Submandibular gland, Sublingual gland, Minor salivary glands of inferior oral cavity
- CN IX (tympanic nerve, lesser petrosal nerve) –> Otic –> CN V3 branch –> Parotid gland
Teeth
The crown of a tooth projects above the gingiva and is separated from the root by a constricting neck. The root is inserted into the bony socket (alveolus) of the alveolar ridge of either the maxilla or mandible
by an immovable gomphosis joint. Teeth have a labial/buccal surface facing the lip or cheek and a lingual surface facing the tongue.
Periodontal ligaments support the teeth in the alveolar socket and provide sensory information about tooth position and the forces acting on the teeth
Sets of teeth
There are two sets of teeth
• Deciduous - 20 teeth
• Permanent 32 teeth: 2 incisors, 1 canine, 2 premolars, 3 molars in each quadrant
Nerve supply to the teeth
Nerve supply to the teeth comes from branches of the trigeminal (CN V) nerve:
• maxillary (CN V2) nerve gives the superior alveolar
nerves (posterior, middle and anterior). The latter two branches come from the infraorbital nerve.
• mandibular nerve (CN V3) gives the inferior alveolar
nerve
Blood supply to the teeth
Blood supply to the teeth is via the maxillary artery.
• upper jaw (maxilla)
• posterior superior alveolar artery directly off the
maxillary artery
• anterior superior alveolar artery a branch of the
infraorbital artery.
• lower jaw (mandible)
• inferior alveolar artery
Functions of the Tongue
The tongue functions in:
• taste
• speech
• mastication
• deglutition
• absorption of medications: Deep lingual veins visible near the tip of the tongue just beneath the mucous membrane absorb certain sublingual
medications directly into the venous system.
Foramen cecum
The dorsum of the tongue has a median sulcus that divides it into lateral halves.
This terminates posteriorly in a pit, the foramen cecum, (embryologic origin of the thyroglossal duct).
Sulcus terminalis
It is the sulcus terminalis which separates the
• anterior two-thirds (oral portion) of the tongue (apex & body) from the
• posterior one-third (pharyngeal portion) of the tongue
