13 - GI: Mouth & Esophagus Flashcards
mastication and deglutition
Alimentary canal functions
names only
- Ingestion
- Secretion
- Mixing and Propulsion
- Digestion
- Absorption
- Defecation
external mouth anatomy
diagram goodnotes + some info
label and test
frenulum: restrict lip or tongue movement
hard palate: bone, part of skull covered by stratified squamous cells (mucous membrane)
soft palate: muscular layer covered by mucous membrane
uvula: protrudes from soft P, high density of receptors for gag reflex
gustation
basic definition + info
sense of taste
5 tastes: sweet, salty, bitter, sour, umami (savory)
sensed via papillae
papillae
types, facts, location (GN)
roughly 10 000 tastebuds (TBs) in the tongue, located on the papillae
TYPES:
- vallate: 12, 100-300 TBs each
- fungiform: 5 TBs each, raised bumps + scattered on tongue
- foliate: in lateral margins degenerate in childhood
- filiform: tactile sensations, raised and scattered
What happens if gustatory receptor cells are killed? (eg: tongue gets burnt)
They regenerate, stem cells in the tongue differentiate
Gustation: Neural Pathways
basic structures + pathway (GN)
papillae to cranial nerves:
vagus (X): back of throat (epiglottis + pharynx)
glosspharyngeal (IX): back 1/3 of tongue (vallate p’s)
facial (VII): front 2/3 of tongue (fungiform p’s)
tactile – trigeminal (V): front 2/3 (filiform p’s)
medulla: gustatory nucleus
thalamus
insula of cerebrum: gustatory cortex
Olfaction
basic definition
sense of smell
Olfaction: Neural pathway
structures involved + pathway
molecules enter nasal cavity
olfactory glands produce mucus
odorant molecules must dissolve in mucus for neural transduction to occur
olfactory epithelium: olfactory sensory neurons
through holes in cribriform plate
olfactory bulb: olfactory tract
!!does not synapse in thalamus!!
temporal cortex in cerebrum: olfactory cortex
Teeth
names, location, purpose
16 above, 16 below
Incisors: cutting (2)
Canines (cuspids): tearing (1)
Premolars: crushing (2)
Molars: grinding (3) last row is wisdom teeth
GN diagram, # is how many types (4 of each)
Dentitions
names
deciduous (baby teeth set)
permanent (adult set)
supernumary teeth: extra teeth
Tooth (internal anatomy + innervation)
diagram goodnotes
only highlighted labels
Mastication
basic definition + info
chewing
partly involuntary (cheek muscles stretching)
Intrinsic muscles of the tongue
names, location, innervation (diagram goodnotes)
all hypoglosseal (XII)
superior and inferior long: shortens tongue
transverse: contracts horizontally (tongue gets skinnier)
vertical: flattens tongue
run from the back to the front of the tongue
Extrinsic muscles of the tongue
names, location, innervation (diagram goodnotes)
vagus (X)
palatoglossus
hypoglosseal (XII)
styloglossus
hyoglossus
genioglossus
attach to the base of the tongue + bones
named after the bone they connect to
Hyoid bone
location + facts (diagram goodnotes)
does not attatch to any other bone
typically fractures if person is strangled
Muscles of mastication
names, location, innervation (diagram goodnotes)
trigeminal (V)
act on the mandible
provide force for chewing:
- temporalis
- masseter
move mandible side to side:
- medial and lateral pterygoid
muscles of facial expression
names, location, innervation (diagram goodnotes)
facial (VII)
Buccinator: tension in cheek
Orbiculator Oris: circle of fibers around the lips
Mastication vascular supply
names, location (diagram goodnotes)
- superficial temporal a./v.
- external carotid a., external jugular v.
- maxillary a./v.
- facial a./v.
Salivary glands
names, locations, saliva type (GN)
parotid: only serous + amylase
submandibular: mostly serous + amylase
sublingual: mostly mucous + lipase
serous = watery, more proteins
mucous = thick, more mucin
Saliva composition
general
- water
- amylase (digestive)
- mucin (thickens)
- lysozyme (immune)
- defensins (immune)
- IgA (immune)
- electrolytes (sodium and chloride)
Nervous input for saliva
parasympathetic (VII and IX)
- increased saliva production of watery, enzyme rich saliva
- triggered by chewing
sympathetic
- decreased saliva production in parotid and submandibular
- increased production of thick, mucin rich saliva from sublingual
Deglutition
basic definition + phases
swallowing
- Voluntary
- oral cavity and tongue - Pharyngeal
- reflex initiated by stretch of oropharynx
- closing off nasal cavity and trachea - Esophageal
- peristalsis
Esophagus anatomy
relational, features, histology (GN)
- upper esophageal sphincter
- kink: trachea (left main bronchus) compresses
- kink: left atrium compresses
- through esophageal hiatus in diaphragm
- lower or gastroesophageal sphincter
Histology
- mucosa stratified squamous epithelial layer
- submucosa
- muscularis
- adventitia (connective tissue)
Peristalsis
alternating waves of muscle contraction and relaxation used to move food through the GI tract
circular muscles contract above food to push it down
