Flashcards in GI Histo Deck (75):
space between lip, cheeks, and teeth
hard and soft palates, tongue, floor of mouth, and entrance to oropharynx
Oral cavity proper
What are the 3 types of mucosae in the oral cavity
Masticatory: SSE keratinized or parakaratinized
(mucosa on gingiva and hard palate)
Specialized: SSE keratinized
(dorsum of the tongue)
Lining: SSE non keratinized
What makes the specialized mucosa specialized?
Different/unique types of papillae
Strengthen mucosal stability of masticatory mucosa
Deep papillae from the underlying lamina propria
what is the distribution of papillae on the tongue?
-Ant 2/3 tongue = filiform with scattered fungiform
-Divides the ant 2/3 from the post 1/3—there are 8-12 circumvallate papillae in a row
-on lateral edges of tonge: foliates
Papillae on tongue that does not have taste buds
Filiform (fount on ant 2/3—the taste buds are found in the fungiform papillae in this area, they are scattered among the filiform)
Papillae on tongue that is keratinized
Filiform and some fungiform
What are the cells found in taste buds?
Sensory, supporting, and basal
Predominate cell type in a taste bud
Cells in the taste bud that synapse with afferent nerve fibers
What are the known tastes
Sweet, salt, bitter, umami
What is umami??
The taste of L-glutamate in monosodium glutamate (MSG) and asparagus
T or F: a sensory cells has a heterogenous mixture of sensory receptors
F: each sensory cell contains only 1 receptor type
T ort F: taste buds contain a heterogenous mixture of sensory cell types
What type of taste is generally limited to the back of the tongue
**all others are distributed all over the tongue
Other than the tongue where are taste buds also found?
Roof of mouth
What are the major salivary gands?
Parotid, submandibular, and sublingual
Where are the minor salivary glands found?
CT of the cheek, tongue, and palate
What are the cell types in salivary gands?
Serous (pink) and mucous (blue)
What do the serious cells in salivary glands secrete?
Water substance with protein, amylase, and lysozyme
Describe the structural organization of the salivary glands
Acini of mucosal cells or serous cells covered in myoepithelical cells that when contracted will force secretions of acini into intercalated ducts and striated ducts
What is the difference between intercalated ducts and striated ducts?
Intercalated ducts are simple cuboidal and secrete and abs to modify secretion
Striated ducts are simple cuboidal to simple columnar and striations are caused by basal plasma membrane and aldso modify secretions
??? not too sure need to wiki
Aka for excretory ducts of salivary glands
**do not modify secretions
Distinctions of the 3 salivary glands (types of acini)
Parotid is purely serous acini
Submandibular is mixed but mostly serous
Submandibular is mixed
Sublingual is mixed but mostly serous
What is a serous demilune and what gland(s) contain it?
In submandibular glands: serous cells forming a cap over the mucinous acini
Buffers content in oral cavity
Digestive enzymes present in saliva
Amylase and lipase
Role of saliva in health of teeth
Has protein that forms a protective film
Contains Ca and PO4 for minetalization of teeth
Are Abs preset in saliva
Controls mucosal movement, vascular diameter, secretion of mucosal and submucosal glands of GI tract
What are the 4 concentric layers of the wall of the alimentary canal
Mucosa, submucosa, musclaris externa, serosa/adventitia
3 principal functions of the mucosal layer of the GI tract
1. Secretion (lubrication and digestive enzymes)
2. Absorption (vit, H2O, electrolytes, bile, cholesterol, important metabolic substrates)
3. Protection: (barrier)
Functions of submucosa of GI tract
Contains blood and lymph vessels, nerve plexus, occasional glands
Functions of the muscularis externa
Inner circular layer contracts to compress and mix contents while outer longitudinal layer contracts to propel food
Forms sphincters along digestive tract
Inner circular layer
Describe the epithelium of the esophagus
Contains esophageal cardiac glands
Mucosa (mucous glands at upper and lower esophagus)
Contains mucous secreting tuboaveolar glands
Contains esophageal glands proper
type of muscle in muscularis externa in the esopagus
skeletal (upper 1/3) and smooth (lower 2/3)
(voluntary to involuntary)
what are rugae
large longitudinal gastric folds that assist in digestion (mucosa and submucosa)
What type of epithelium lines the stomach
in what later are gastric glands found?
lamina propria of the mucosa
forms the core of the rugae
what are gastric pits?
invaginations of mucosal surface into the lamina propria forming "holes" in the gastric surface
what does surface mucosal cells produce?
alkaline mucous to protect stomach lining
**in large mucinogen granules
has acidophillic granules and secrete pepsinogen
are acidophillic and secrete HCl
what cells secrete intrinisic factor
enteroendocrine cells secrete gastric hormones into the ____
lamina propria (these cells are found in the gastric glands which reside in the lamina propria)
gastric glands secrete there secretions into the gastric lumen via the
what cells reside in the gastric glands
chief cells, parietal cells, enteroendocrine cells, stem cells, and mucous cells (at the neck of the gland)
large eosinophillic pyramidal shaped cells
chief cells are (acidophillic or basophillic)
where are the stem cells of the stomach found?
isthmus (new cells will move up to become mucos cells are move down to become gland cells
do parietal, chief cells, or enteroendocrine have a longer life span?
parietal (6 mos) > chief cells and enteroendocrine (3 mos)
diff between rugae and gastric glands/pits
rugae are elevations that contain mucosa and submucosa whereas pita are just invaginations of the mucosa only
what are the 4 modifications of the intestinal wall that allows it to increase surface area for absorption
1. plicae circulares
3. crypts of lieberkuhn
What are plicae circulares
transverse folds in mucosa that have a core of submucosa (increases SA 3 fold)
in what section of the small intestine are the plicae circulares more common
villi increase the SA ___ fold and microvilli increase SA ___ fold
villi = 10 fold
microvilli = 100 fold
Surface epithelium has indentations (arrows) that lead to
crypts of lieberkun
what causes the movement of the microvilli?
actin contracts to contract terminal wweb and spread the microvilli
the primary absorptive cell, found on the villi, the general surface and in the glands
enterocytes are attached to neighboring cells by
in the glands, the enterocytes also secrete
water and electrolytes
found in the base of crypts, basal basophilia, intensely acidophilic granules in the apical region !
what do paneth cells secrete?
lysozyme (digests bacterial cell wall) and other anti-bacterial surfaces
overlie lymphatic nodules!
comprise most cells in the lower half of the gland!
intermediate cells (stem cells)
cells in the epi of the small intestine that can phagocytose certain bacteria and protozoa
endocytose microorganisms and macromolecules from intestinal lumen and discharge them into the underlying lymphatic tissue