12 - mouth & esophagus

what are the parts of the alimentary canal

ISMDAD - ingestion, secretion, motility, digestion, absorption, defecation

mastication

to chew

deglutition

to swallow

vallate papillae

100-300 taste buds each (V shaped at the back)

fungiform papillae

all over tongue ; each has 5 taste buds

foliate papillae

side folds of the tongue

what are the 3 cranial nerves involved with taste

facial (VII), glossopharyngeal (IX), vagus (X)

what nerve is used for sending signals from the tongue

trigeminal (V)

four types of teeth and function

incisors (cutting), canines (tearing), premolars (crushing), molars (grinding)

two types of dentitions

deciduous, permanent

enamel

hardest substance in the body, harder than bone (95% calcium salts), after it’s formed it doesn’t grow again

which nerve innervates tooth aches

trigeminal (CN V)

4 intrinsic muscles

superior longitudinal, inferior longitudinal, transverse, and vertical

what are the intrinsic muscles innervated by

hypoglossal

3 extrinsic muscles and their function

hyoglossus (retract tongue)

genioglossus (sticks tongue out)

styloglossus (elevates tongue)

what innervates the extrinsic muscles

hypoglossal

muscles of mastication

temporalis (helps chew)

masseter (talking and chewing)

pterygoids (jaw movement)

what are they innervated by?

trigeminal

2 facial expressions muscles

buccinator (keeps cheeks taut)

orbicularis oris (kissing)

what innervates them

facial

3 glands in mouth + nerve

sublingual (makes saliva thicker) - facial

submandibular (watery saliva) - facial

parotid (amylase) - glossopharyngeal

3 stages of deglutition

voluntary

pharyngeal

esophageal

voluntary stage

tongue forces food down throat

pharyngeal stage

swallowing, uvula protects nasal cavity, epiglottis protects trachea, upper esophageal sphincter (UES) relaxes

esophageal stage

esophagus carries food down, lower esophageal sphincter (LES) relaxes to let food into stomach

espophagus anatomy

extends from oropharynx, passes through the esophageal hiatus

what are the four layers of its walls

1. mucosa (stratified squamous epithelium)

2. submucosa

3. muscularis

4. adventitia

peristalsis contractions

bring food down to stomach

circular muscle: narrows tube to force food down

longitudinal muscle: widens tube to move food down