Histo; Oral Cavity & Esophagus Flashcards
What are the main things that happen across the alimentary canal mucosa? What are its 4 specific functions?
most substances enter the body... Secretion Absorption Barrier Immunological Functions
Where can an angular defect show up in the oral cavity?
When you don’t carefully line up the vermillion/upper lip…very difficult to correct if sutured incorrectly…
What are the 2 general categories of the oral cavity? What are the structures contained in the cavity?
Vestibule + Oral Cavity Proper
tongue
teeth
salivary glands (major & minor) & tonsils
What is the oral cavity lined w/? What are the 3 different regions?
MUCOSA
Region 1: Gingiva & hard palate
Region 2: everything else except the tongue
Region 3: tongue
What type of mucosa lines the hard palate & the mucosa?
masticatory mucosa
keratinized & parakeratinized stratified squamous
What is parakeratinized stratified squamous?
this is stratified squamous epithelium that has cells that retain their nuclei on the top layer…
What type of mucosa is everywhere else in the oral cavity except the tongue?
Lining mucosa
stratified squamous & parakeratinized stratified squamous
What type of mucosa is on the tongue?
Specialized Gustatory Mucosa
papillae & taste buds on the dorsum of the tongue
What happens when your tongue burns?
abnormal keratinization of your tongue
What is the gingiva?
basically the gums
Which part of the lip is the vermillion?
the red portion
considered red b/c of the capillaries underneath it…
What type of epithelium is found @ the vermillion?
parakeratinized epithelium
What type of muscle is found in the lip?
skeletal muscle
What types of glands are found in the lip?
minor salivary glands (labial glands)
How many teeth are baby teeth? Another name for this? How many are adult teeth? Another name for this?
20 deciduous (baby) teeth 32 permanent (adult) teeth
What are the 2 main parts of teeth? What make each part?
Enamel–>ameloblasts
Dentin–>Odontoblasts
What are the 3 main structural parts of the teeth? What defines these boundaries?
Crown: until the gum starts
Neck: until the gum line ends
Root: below the gum line
What is the enamel…made by ameloblasts derived from?
Ectoderm
What is the dentin composed of? It is made by odontoblasts…derivation?
dentin tubules–>extend into the pulp
neural crest cells
T/F The enamel doesn’t regenerate.
TRUE. IT DOES NOT REGENERATE…take care of those little guys…
What is contained in the pulp chamber? Where is the pulp chamber?
nerves & blood vessels
underneath the dentin…
What depth does the dental hygienist measure at the dentist’s office?
the gingival sulcus
this sulcus enlarges until the gingival epithelium is below the crown & into the neck of the tooth & at that point the dentin tubules are exposed…
pressure sure that’s a bad thing…
What is on the anterior 2/3 of the dorsum of the tongue?
four types of lingual papillae
What is on the posterior 1/3 of the dorsum of the tongue?
lingual tonsil
What is on the ventral surface of the tongue?
lingual frenulum
What is the clinical significance of the lingual frenulum?
on either side of it are deep lingual veins…this is a great site for drug delivery
What divides the anterior 2/3 from the posterior 1/3 of the dorsum of the tongue?
a V-shaped sulcus terminalis
just posterior to the circumvallate papillae
What are the 4 different kinds of papillae found on the dorsum of the tongue?
Circumvallate papillae
Foliate papillae
Fungiform papillae
Filiform papillae
Where are the circumvallate papillae located & what glands are they associated with?
just anterior to the sulcus terminalis (divides the posterior & anterior portions of the tongue)
associated w/ Ebner’s glands
Where are the foliate papillae located? Are they abundant in adults?
sort of located on the side of the tongue
not abundant in adults…seen more in newborns
Where are the fungiform papillae located? Do they have taste buds? Are they abundant?
located on the margin of the tongue
They DO have taste buds.
They are more abundant that foliate or circumvallate, but less abundant than filiform.
Where are the filiform papillae located? Do they have taste buds? Are they abundant?
appear to be on the anterior portion of the tongue…dorsum of the tongue…
They DO NOT have taste buds.
Their function is scrape & provide friction b/w food & the tongue & food…
Dogs & cats have a lot of these…
They are the most numerous type of papillae in the human tongue…
Where is the median sulcus located?
the middle of the dorsum of the tongue…
Where is the foramen cecum located?
a little posterior to the circumvallate papillae
How would you describe circumvallate papilla?
They have a moat around them…they are large & can be seen in the back of people’s tongues. They have taste buds & Ebner’s glands.
What are Ebner’s glands?
These are glands associated w/ the circumvallate papillae…they are seromucous glands…they form a fluid that clears out the surface of the papilla.
They are in some ways similar to Bowman’s glands.
Where are taste buds found on the tongue?
Fungiform, Foliate, & Circumvallate papillae
Found on oral pharynx, soft palate & posterior surface of the epiglottis
What is a taste bud composed of?
neuroepithelial sensory cells
supporting cells
basal cells
Where can tastes be detected?
All over the tongue. Rumor that there are regions.
Umami senses glutamate…often found in what?
MSG
What are the 2 parts of the palate?
Hard palate (anterior 2/3) Soft palate (posterior 1/3)
What makes up the hard palate?
bone
keratinized stratified squamous
What makes up the soft palate?
skeletal muscle
surface that faces the oral cavity: stratified squamous epithelium
surface that faces the pharynx: respiratory epithelium
**contains palatine glands
What are the major salivary glands? What are the main 3? Which is the largest?
paired glands with long ducts emptying into the oral cavity
Parotid (largest)
Submandibular
Lingual
What are the minor salivary glands?
located in the submucosa of different parts of the oral cavity…
Where does the parotid gland empty into? Where is it located? What is it considered? What is a clinical correlation?
Vestibule
It is located above the 2nd molar.
It is the largest major salivary gland.
It is the culprit of mumps.
Where do the sublingual & submandibular glands empty into?
the oral cavity proper…
How is salivary volume modulated by autonomics?
With parasympathetic activation–>secretion increases & volume increases
With sympathetic activation–>secretion decreases & volume decreases (reason for dry mouth during public speaking)
How many salivary glands are there? What types of secretions does each one have? What is their contribution to the saliva? How much saliva do they all in total produce each day?
**note these are paired glands
Parotid: Largest gland; serous secretions; 30% of the saliva…
Submandibular/Submaxillary Gland: mixed gland, but mainly serous…
60-70% of the saliva.
Sublingual: mixed bland, but primarily mucous
10% of the saliva
1-1.5 L saliva/day
How doe mucous secretory cells secrete their mucus?
thru a series of ducts…
Glands secret lysozyme into the saliva…what else? Which immunoglobulin is found secreted in saliva? Why is it special?
IgA
a dimer that is broken down like other immunoglobulins…
Histologically…how can you tell mucous secretory cells from serous secretory cells?
Mucous look cleared out on the inside.
What is the structural arrangement of the mucous & serous glands? What ducts do they secrete into?
acini aka alveoli
OR tubules
Ducts:
intercalated, striated, interlobular ducts…
What modulates the salivary osmolarity & composition?
Duct Epithelium
What are the 3 major cell types found in salivary glands?
serous & mucous cells
myoepithelial cells (have myosin & actin in them)
Plasma cells
What do myoepithelial cells do?
they squeeze the saliva into the oral cavity
Note: they have myosin & actin
What do the plasma cells secrete?
IgA
Which salivary glands have serous demilunes? What does this mean?
Submandibular Gland
Sublingual Gland
**this is found on any glands that have mixed secretions…
**it is really just an artifact from traditional preparation techniques…
What constitutes gut associated lymphatic tissue?
diffuse lymphatic tissue
lymphatic nodules (found in the submucosa or lamina propria)
Tonsils (Waldeyer’s Ring)
What makes up Waldeyer’s Ring?
palatine tonsils
tubal tonsils
pharyngeal tonsils (adenoids)
lingual tonsil
What do you see a lot of in diffuse lymphatic tissue?
plasma cells producing IgA
In the large intestine where are the lymphatic nodules found?
They are found starting in the submucosa & extending upward…
What are the layers of the mucosa?
epithelium
basal lamina
Lamina propria
muscularis mucosae
Where are there submucosal glands in the GI tract?
in the duodenum & the esophagus
Where is the Meissner’s plexus & what is another name for it?
it is located b/w the submucosa & the muscularis
it is also called the submucosal plexus
What is the muscular is layer composed of?
inner circular
outer longitudinal
What is found in b/w the inner circular & outer longitudinal layers of the muscularis layer?
myenteric plexus or Auerbach’s plexus
What are the 4 histological layers of the digestive tract?
Mucosa
Submucosa
Muscularis
Adventitia
Where do you find adventitia vs. serosa?
when you are inside the peritoneal cavity: serosa
outside the peritoneal cavity…like on the esophagus: adventitia
**adventitia above the diaphragm…serosa below the diaphragm.
Where is it difficult to control bleeding? Why?
In the esophagus…b/c usually the solution is to push the bleeding portion up against a bone…not possible in the esophagus.
What are the important features of the layers of the esophagus?
Mucosa: single longitudinal layer
Submucosa: esophageal glands proper
Muscularis Externa: skeletal vs. smooth muscle
Adventitia above diaphragm; Serosa below diaphragm
What’s the deal w/ the muscle layers in the muscularis externa of the esophagus?
Upper 1/3 is skeletal muscle (voluntary control)
Middle 1/3 is mixed
Lower 1/3 is smooth muscle
What are the 2 sphincters related to the esophagus?
Upper Esophageal Sphincter: separates the pharynx from the esophagus
Lower Esophageal Sphincter: separates the esophagus from the stomach
What’s another name for the UES?
cricopharyngeal muscle
What’s another name for the LES?
gastroesophageal sphincter
Which sphincter is involved in GERD? What does this stand for? What is the distinction b/w the anatomic sphincter & the physiological sphincter?
Gastro esophageal reflux disease
gastroesophageal sphincter aka lower esophageal sphincter
**anatomic sphincter: the muscles of the sphincter
physiological sphincter: the stuff surrounding the sphincter helps in its action…obesity compromises this…
What are esophageal varices?
they are dilations of the submucosal veins in the lower 1/3 of the esophagus…can lead to bleeding
associated w/ portal hypertension from cirrhosis
