Oral Cavity and Taste Flashcards
oral vestibule
this is the area between the lips/cheeks and the teeth
oral cavity proper
this is the area where the tongue is
cheeks
- the lateral walls of the oral cavity
- the buccinator muscle is important for supporting these and helps to maintain food in the mouth when chewing
- innervated by cranial nerve 7 (facial nerve)
lips
-these close the oral cavity
gingivae
- these are the gums
- these cover the alveolar processes of the upper and lower processes of the upper and lower jaws and surround the necks of the teeth
palate
- this is the roof of the mouth and is made up of the hard palate and the soft palate
hard palate
- this is the anterior 2/3 of the palate (roof of the mouth)
- this is the bony roof of the oral cavity formed by the maxillae and the palatine bones
- this separates the oral cavity from the nasal cavity
soft palate
- this is the posterior 1/3 of the palate (roof of the mouth)
- this is soft and muscular
- it is a fleshy posterior extension of the hard palate
- it separates the oral cavity form the nasopharynx during swallowing
uvula
- dangly fleshy extension of the soft palate
- it hangs from the posterior margin of the soft palate and prevents food from entering the pharynx too soon
functions of the oral cavity
- sensory analysis of food before swallowing
- mechanical digestion through teeth, tongue and palatal surfaces
- lubrication by mixing ingested material with mucus and saliva
- limited chemical digestion of carbs by salivary amylase and lipids by lingual lipase
palatoglossal arch
- this is one of the paired muscular folds that opens the oral cavity into the oropharynx
- this is made of the palatoglossus muscle
- this extends between the soft palate and the base of the tongue
- this is anterior to the palatine tonsils
palatopharyngeal arches
- this is one of the paired muscular folds that opens the oral cavity into the oropharynx
- extends between the soft palate to the side of the pharynx
- this is made up of the palatopharyngeus muscle
- this is posterior to the palatine tonsils
tongue
- begin mechanical digestion through abrasion and distortion
- manipulation to assist in chewing to prepare food for swallowing
- sensory analysis by touch temperature and taste receptors
bolus
lingual frenulum
- this attached the tongue to the floor of the oral cavity
- if this is too tight it may cause issues with speech
intrinsic muscles
these originate and insert within the tongue
- they are there to change the shape of the tongue
- important for moving around the bolus
- assist the extrinsic with precise movements (speech)
extrinsic muscles
- these originate away from the tongue and insert on the tongue
- these physically move the tongue in space
- genioglossus
- styloglossus
- hypoglossus
- palatoglossus
- they are all innervated by the hypoglossal nerve except for palatoglossus
genioglossus
- this is an extrinsic tongue muscle
- this is to protract the tongue outward
styloglossus
- this is an extrinsic tongue muscle
- this retracts and elevates the tongue
hypoglossus
- this is an extrinsic tongue muscle
- this retracts and depresses the tongue
palatoglossus
- this is an extrinsic tongue muscle
- this elevates the tongue and pulls the soft palate down
- this is the one extrinsic muscle that is not innervated by the hypoglossal nerve
- this is innervated by the cranial nerve 10 (vagus nerve)
muscles of matication
o Temporalis
o Masseter
o Medial pterygoid
o Lateral pterygoid
- these all insert on the mandible
- these do not open the mouth
- these close the mouth
- when these muscles relax, the mouth opens
- these are skeletal muscle
- these are not muscles of facial expression
- all are innervated by the mandibular branch of cranial nerve five
temporalis
this elevates and retracts mandible
- this is the largest of the muscles of mastication
masseter
this elevates and protracts the mandible
lateral and medial ptergoids
- these protract and move the mandible from side to side
- these have a different angle which allows for them to do this action –> structure governs function
** the medial also elevates the mandible
temporomandibular joint
- it is a synovial joint
- very important for mastication
- diarthrotic hinge joint between the head of the mandible and temporal bone
- the articular disc (this is a fibrocartilage in the joint)
- ligaments that provide stability
( one of the only mobile joints of the entire skull )
Saliva
- this acts to moisten our food and lubricates it as we prepare to go into the GI tract
- 95% water and 0.5% solutes
it is a combination of all the secretions from the salivary glands (70% from submandibular, 25% from the parotid, 5% from sublingual)
Salivary Glands
- these can be extrinsic or intrinsic
- these are innervated by parasympathetic innervation (CN 7 and CN 9)
- the sympathetic innervation is the superior cervical ganglia
extrinsic salivary glands
these are the ones that produce the majority of the saliva in the mouth
- parotid glands
- submandibular glands
- sublingual glands
intrinsic salivary glands
these are little unicellular glands found throughout the oral cavity that produce small amounts of saliva
parotid gland
- this is the largest salivary gland
- is anterior to the ear
- the parotid duct is what drains the secretions
- innervated by: CN IX (glossopharyngeal nerve)
- CN VII runs through this gland –> this is important to remember because if there is a tumor or surgery there could be damage to this gland and could damage the facial nerve
parotid duct
this runs parallel to the zygomatic arch and pierces the buccinator
submandibular gland
- along the inferomedial surface of the body of the mandible (below the mandible)
- this gland produces the majority of the saliva (60-70 percent)
- drains into the submandibular duct
- innervated by the facial nerve (CN VII)
submandibular duct
- this is under the tongue and what is secreting majority of the secretions of saliva entering the mouth
- opens up onto either side of the frenulum
sublingual glands
- covered by the mucous membrane of the floor of the mouth
- it is inferior to the tongue
- it is a small gland and only contributes the 3-5% of the total saliva
- this drains into multiple tiny sublingual ducts that open onto the inferior surface of the oral cavity on either side of the frenulum
- innervated by CN VII (facial nerve)
salivary reflex
- food in the mouth will stimulate receptors in the mouth or by stimulating the taste buds and this leads to the secretion of saliva
- parasympathetic innervation speeds up secretion of all glands
crown of tooth
this is the upper exposed portion of the tooth that exposed out of the gingiva
neck of tooth
- this marks the boundary between the root and the crown
- this is a narrowed portion of the tooth
root of tooth
- this is where you find the neurovasculature and the vessels
- this is at the base of the tooth
the layers of the tooth
- pulp cavity
- dentin
- cementum
- enamel
enamel
- this is the outer most layer of the tooth
- this is a crystalline material that is similar to the mineral composition of bone
- this covers the crown
- it is the hardest structure on the human body
dentine
- this is just deep to the enamel
- this makes up the majority of the tooth
- it is a fibrous connective tissue
- it is a mineralized matrix that does not have any living cells
cementum/ cement
- this is a thin layer that surrounds the dentrin in the alveolar process
- this anchors the tooth to the alveolar process of the bone
periodontal ligaments
- these are assisting in the anchoring of the root into the alveolar process
- this is superficial to the cement and extends from teh cement to the bone
gomphosis joint
- this is the roots + the dental alveoli + the periodontal ligaments
- this is what anchors the tooth into the socket
incisors
- these are the blade shaped teeth at the cont of the mouth
- typically going to have four on the top and bottom
-these grab and clip food
canines
- these are also called cuspids
- these are conical teeth with sharp ridgeline and a pointed tip
- these tare and shred food
premolars
- these are also called bicuspids
- these have flattened crowns with 2 prominent rounded cusps
- these crush, mash, and grind
molars
- have large flattened crowns with 4 or 5 prominent rounded cusps
- these are adapted for crushing and grinding
- the upper jaw molars have 3 roots
- the lower jaw molars have 2 roots
there are three molars on the top and the bottom
- the third molar is the wisdom tooth
deciduous teeth
- these are the teeth that appear first and are going to be lost and replaced
- the periodontal ligaments and roots of the teeth erode
- there are no premolars
- they only have ten teeth on the top and bottom
- the teeth all erupt through the gums at different times of development
- the incisors are typically first and move out from there
- it can take up to two years to get them all in
permanent teeth
- these are the teeth that come in and replace the deciduous teeth
- there are more of these and there are premolars
- typically there are 32 teeth (16 on the top and bottom)
- the third molar is often removed (the wisdom teeth) leaving people with 28 teeth
gustatory cells
- these are taste receptors found in taste buds that are distributed over the tongue surface and adjacent portions of the pharynx and larynx
- there can be 40-100 gustatory epithelial cells on each taste bud
- these contain taste hairs (microvilli)
taste hairs
these are microvilli that extend into surrounding fluid
- they extend through narrow openings called taste poors
- these essentially trap taste and then this depolarizes the cell and gustatory cell and then the neurons send the info
taste bud
this is a specialized organ for taste
- composed of many gustatory cells
papillae
these are epithelial projections off of the tongue
- filiform papillae
- fungiform papillae
- vallate papillae
- foliate papillae
filiform papillae
these are short and bristle like
- these are distributed over the anterior 2/3 of the tongue
- these are the most common type
- these do not have taste buds
- these are what give the tongue the whitish color
fungiform papillae
these contain taste buds
- these are larger bumps on the tongue
vallate papillae
- these are the least numerous but the largest (we only have about 10-12 of these)
- they are in an inverted V shape on the posterior dorsal surface of the tongue
- majority of the taste buds are here
what do we need to know about the different tastes
- there are 6 different tastes if we include water
- sweet
- salty
- bitter
- sour
- umami (savory, caused by glutamate)
- water receptors (in the pharynx)
gustatory pathway
- this is what allows for the ability to taste
- the taste hairs trap the taste which leads to depolarization of the gustatory cell
- this signals the axon and these travel through CN VII and IX to the brainstem
- taste information is then sent to the thalamus
- taste fibers project from the thalamus to the primary gustatory cortex in the insular cortex
what portion of the tongue is innervated by the facial nerve
CN VII innervates the anterior 2/3 of the tongue for the special sense of taste
what portion of the tongue is innervated by the glossopharyngeal nerve
CN IX innervates the posterior 1/3 of the tongue for the special sense of taste
this also innervates the posterior 1/3 of the tongue for the general sense of touch (pressure, hot or cold)
what portion of the tongue is innervated by the vagus nerve
CN X innervates a small portion of the posterior tongue for the special sense of taste
CN X innervates a portion of the posterior tongue for the motor innervation because it innervates the palatoglossus muscle which is the one exception for tongue muscle innervation
what portion of the tongue is innervated by the lingual nerve
CN V innervates the anterior 2/3 of the tongue for the special sense of touch (pressure, hot, or cold)
what is the importance of the hypoglossal nerve for the tongue innervation
CN XII is important because it innervates the muscles of the tongue allowing for motor innervation
** with the exception of the palatoglossus muscle
