12 - Mouth & Esophagus Flashcards
What are the basic processes of the alimentary canal
ingestion
secretion
motility: movement down a athway
digestion
absorption
defecation
What structures help with mastication (chewing)
teeth
cheek
tongue
lips
muscles of mastication
salivary glands (3 pairs) – 1 to 1.5 liters/day
Where is the oral cavity
space between the gums and teeth to the fauces (passages)
What are the structures of the oral cavity
lips
gums (mucous membrane)
teeth
cheek (keep food in)
superior labial frenulum (where lip is tied)
inferior labial frenulum
hard palate (bony structure of skull)
soft palate (skeletal muscle covered in mucous membrane to keep food in)
uvula (sensory receptors – vomit response)
lingual frenulum (restricts tongue movement)
opening of duct of submandibular gland (salivary gland duct)
What are primary tastes
sweet
bitter
salty
sour
umami (savory)
Where are taste buds found
on the papillae of the tongue
What are the types of papillae
vallate papillae
fungiform papillae
foliate papillae
filiform papillae
vallate papillae
12 each containing 100-300 taste buds
fungiform papillae
scattered over tongue each containing 5 taste buds
foliate papillae
in the lateral margins of tonuge – degenerate in childhood
filiform papillae
tactile sensations and friction
contains gustatory receptor cells (sensory neurons)
What are the cranial nerves involved in gustation
Where are they located
facial nerve (CN VII) – anterior two thirds of the tongue
glossopharyngeal nerve (CN IX) posterior one third of tongue
vagus nerve (X) – throat and epiglottis (allow gustatory sensations to come through)
Which nerve is responsible for conveying tactile (touch) sensations from the tongue and tooth aches
CN V – trigeminal nerve (mandibular branch)
What are the types of teeth
What are their functions
Where are they located
incisors – cutting – front 4
canines – tearing – side 2
premolars – crushing – sider 4 (not in primary dentition)
molars – grinding – sidest 6
What are the two dentitions in humans
primary dentitions – deciduous (falling out)
secondary dentitions – permanent
What are the three major outer regions of the tooth
crown
neck
root
What holds teeth in place
periodontal ligaments composed of collagen (requires the formation of vitamin C)
Enamel
hardest substance of the body
(95% calcium salts – harder than bone)
Dentin
consists of 70% calcium salts – also harder than bone
Pulp
supplied by a neurovascular bundle that maintains the connective tissue of the tooth
What are the salivary glands for mastication
What is the function
What nerves innervate
sublingual (mucin + lipase)
- breaks down fats @ low pH
- activated in fight or flight
- gives substance to saliva
- CN IX (hypoglossal)
- SNS
submandibular (serous + amylase)
- CN VII (facial)
parotid (serous + amylase)
- watery saliva –> lubricates food
- breaks down starches
- plaque build up where saliva is secreted
- CN VII (facial)
What do the intrinsic muscles of the tongue do
help to change the shape of the tongue to aid in speech and swallowing
What are the three groups of the intrinsic tongue muscles
longitudinal muscles (sup and inf – legnth of tongue)
- shorten tongue
transverse muscles (left to right)
- think tongue
vertical muscles (up and down)
- flatten tongeu
What are the skeletal muscles of the tongue innervated by
hypoglossal nerve (CN XII)
What covers the tongue
muscous membrane
What do the extrinsic muscles of the tongue
originate outside the tongue and help shape food into a bolus and maneuver food for mastication and swallowing
What muscles attach the tongue to the nearby bones
hyoglossus
- free floating bone
- depresses tongue to floor of mouth for swallowing
genioglossus (genio = chin)
- pertrudes tongue
styloglossus
- long muscles
What nerve innervates the extrinsic muscles of the tongue
hypoglossal nerve (CN XII)
What do the muscles of mastication do
- move the mandible against the maxilla to assist in chewing and talking
- consists of muscles of facial expression that manipulate cheek and lips
What nerve innervates the muscles of facial expression
CN VII – facial
What do the muscles of mastication act on
cheek (buccae)
mouth (oris)
What does the buccinator do
puff cheeks
What does the orbicularis oris do
purse lips
What does the lateral and medial pterygoid do
move jaw side to side of back and forth
What is the temporalis
thin muscle
What does the masseter do
for talking and chewing
(CN V)
Where does the esophagus extend from
oropharynx, through the neck and mediastinum (throax)
Where does the esophagus pass through
esophageal hiatus of the diaphragm and enters the abdominal cavity
What do the structures do that the esophagus passes through
necessitates a slight deviation (kink) in the route of the esophagus
What are the layers of the esophagus
mucosa
submucosa
muscularis
adventitia
What are the layers of the mucosa layer
nonkeratinizd stratified squamous epithelium
lamina propria (connective tissue)
muscularis mucosae (smooth muscles to impose folds
What is the submucosa
muscular layer
highway for nerves and blood vessels connect
what do peristaltic contractions do
help to propel a bolus of masticated food towards the stomach
What are the layers of the muscularis
inner circular
outer longitudinal
What are the layers of the serosa/adventitia
mesothelium
thin connective tissue
How does peristalsis function
coordinated contraction of the inner circular and outer longitudinal muscles
- inner circular: pinch the tube – migrates down the length of the esophagus
- outer longitudinal: shortens tube in ahead of the bolus
How does deglutition (swallowing) work
- voluntary – bolus forced to back of oral cavity by tongue
- pharyngeal – marks the beginning of the involuntary stage of swallowing
a) bolus enters oropharynx
b) stretch of oropharynx elicits a reflex via the brainstem deglutition centre
c) soft pallet and epiglottis close off nasal cavity and trachea, and the upper esophageal sphincter (UES) relax - esophageal – waves of peristaltic contractions propel the bolus towards the stomach – lower esophageal sphincter (LES) briefly relaxes to accommodate bolus
Which types of muscle makes up the esophagus
proximal 1/3 is skeletal
distal 1/3 is smooth muscles
Why is the LES typically closed
to protect the esophagus from acidic gastric contents
