Exam3Lec1Digestive1 Flashcards
What is contained in the upper GI?
- Oral cavity: lip, tongue, salivary glands, teeth
- Esophagus
- Esophago-gastric jxn
- Stomach
The oral cavity has what type of epithelium?
stratified squamous
What type of epithelium does the rough and smooth surfaces of the oral cavity have + what structures
rough surface: keratinized strat sq
* gingiva + hard palate + dorsal tongue
smooth surface: non-keratinized strat sq
* inner surface (mucosal) of lips/cheeks + floor of mouth + ventral tongue
What are the three functional compartments of GI tract?
- Oral cavity: ingestion and fragmentation of food
- Simple passages: transport of food or its residues without significant modification (esophagus and anus)
- Digestive tract: Secretes enzymes induced in breakdown of food: absorbs molecules produced (stomach, small and large bowel)
What are mucosal elevations of anterior, dorsal surface of the tongue?
papillae
What are the 4 types of papillae and describe each one
- Filiform: feather-like shape, long thread like shape
- Fungiform: mushroom-like shape
- Circumvallate: dome-like shape
- Foliate: small lateral folds -> groups of peaks
Tongue has rough surface w/lots of bumps called papillae
Which type of papillae does NOT contain taste buds? What is its role?
Filiform-> role to increase friction between tongue and food
* Fungiform, circumvallate, foliate, oral mucosa and pharyngeal mucosa has tastebuds!
filiform papillae are the most abundant
Cicumvallate papillae are located where? What are they associated with?
- Located in front if the v-shaped sulcus terminalis
- Associated with Ebner’s glands
Explain the process of food components + taste buds
- food components dissolved in saliva penetrate through the taste pore
- Interact with tast receptors causing electrical changes in the taste cells sending impulses to the brain
TONGUE
- What are the principal cell types?
- What are the five stimuli?
- Cell: neuroepithelial cells, supporting cells, basal cells
- Stimuli: sweet, salty, bitter, acid, umami
Inn of Epiglottis, cicumvallate papillae and fungiform papillae via what?
- Epi: CN X
- Cicumvallate: CN IX
- Fung: VII
Taste info reaches the cerbral cortex primarily through what? Some through what?
- Primarily thought the facial (VII) and glossopharyngeal (IX) nerves
- Some through vagus nerve (X)
- Sensory neruons synapse in the medulla located in the solitary nucleus
What is the waldeyer’s ring? fxn?
- The Waldeyer’s ring is made up of the tonsils (tubal, palatine, lingual) , adenoids, and other lymphoid tissue.
- It contains lymphocytes (a type of immune cell) that help the body fight infection and disease.
Taste buds
a. Fxn
b. Lxn
c. Stimuli
a. Fxn: perceive taste + send signals to brain via CN 7 + 9 + 10
b. Lxn: tongue papillae + oral/pharyngeal mucosa
c. Stimuli: sweet, salty, bitter (sour), umami (earthy)
Each taste bud can detect each stimuli
What are the contents and fxn of the oral mucosa?
- Contents: epithelium (stratified squamous) + neutrophils + saliva-> barrier
- Fxn: protective barrier and immune fxn
What are the protective mechanisms of the oral mucosa?
- Epithelium secretes beta-defensins
- Neutrophils secretes alpha-defensins
- Saliva secretes antimicrobial peptides
- Plasma cells = immunoglobulin A secretion into saliva
What is contained within the outer layer and inner layer of the teeth?
Outer layer = enamel -> contains ameloblasts
Inner layer = dentin -> contains odontoblasts
Ameloblasts are only present when?
Developing baby teeth
What is the order of teeth?
ameloblasts ->enamel ->dentin -> odontoblasts
What type of glands are formed when epithelial cells maintain contact with the surface of CT? Without contact?
- With contact: exocrine glands
- Without: endocrine glands
Epitheliral cells proliferate and penetrate CT-> may or may not maintain contact with the surface
What are the exocrine glands in the mouth?
salivary glands
These glands use many ducts to secrete fluid material
Mucous gland vs Serous gland
- Mucous gland = secretes viscous, slimy, glycosylated proteins + water-soluble ->stains light
- Serous gland = secretes watery, non-glycosylated proteins, runny + water insoluble , secretory granules preserved, basophilic rER-> stains dark
What molecules make up saliva? hy
Saliva = alpha amylase, lysozyme, IgA, water, bicarb (HCO3-)
“Salivating Amy Likes Intense Weed Brownies”
What are the major salivary glands of the oral cavity?
Major Glands: Parotid + Submandibular + Sublingual
What are the minor salivary glands?
- lingual, palantine, etc located in the submucosa of oral cavity
- Have short ducts whihc empty directly to the oral cavity
What are the 3 ducts of the major salivary glands? Where are they located?
- Intercalated duct = in serous and mixed glands
- Striated duct = in serous glands
- Excretory duct = interlobular and interlobar
What is the organization of glands and note what type of epithelium it has and/or what is secretes
- Acinus = secretes initial saliva product
- Intercalated duct = simple squam., secrete HCO3- & absorb Cl-
- Striated duct = simple cuboid., secrete K+ + HCO3- & absorb Na+
- Intralobular duct = simple column., striations inbasement mem.
- Interlobular duct = pseudostratified column.
- Main duct = secretes final saliva product directly into the mouth
NOTE: the intralobular duct is made up of the intercalated + striated ducts
What is the function of intercalated duct?
- secrete bicarbonate ion (HCO3-),
- absorb chloride ion (CL-) from the acinar product)
What is the function of striated duct?
- secrete potassium (K+) and HCO3- to the secretion
- reabsorb sodium ion (Na+) from the primary secretion
For each glands below, name what type of gland it is and how it stains
A. Parotid
B. Submandibular
C. Sublingual
A. Parotid: serous only -> stains super dark
B. Submandibular: mixed; serous > mucous ->stains mostly dark
C. Sublingual: mixed; serous < mucous -> stains slightly dark
What is mumps?
Infection in the parotid glands
Transmitted through saliva
Sx = swelling of the gland leading to possible damage to CN 7 (affecting tongue innervation + taste)
What is rabies?
An infection that affects the parotid gland
What is benign salivary tumor?
Sx and Tx
- Affects the parotid glands
- Sx = muscle weakness/numbness d/t tumor disrupting CN 7
- Tx = removal of the parotid gland
- What is Sjogren Syndrome?
- What does it affect?
- What are the symptoms?
Affects ALL salivary glands
* Autoimmune disease where CD4+ immune cells attack & destroy salivary gland tissue (exocrine glands)
* Sx = dry mouth, eyes + enlarged salivary glands with lymphocyte infiltrations
How is the Digestive system organized and note which structures are located in each
- Oral Cavity = mouth + salivary glands
- Simple Passages = esophagus
- GI tract = stomach + small intestine + large intestine
What are the layers of the digestive system? From internal to external
- Mucosa = epithelium ->lamina propria (loose CT) -> muscularis mucosa (2 layers of smooth muscle)
- Submucosa = loose CT
- Muscularis Externa = outer longitudinal + inner circular layer of smooth muscle
- Adventitia (= loose CT) or Serosa (=mesothelium + loose CT)
What type of epithelium is the esophagus lined with?
Strat sq epithelium
What are the contents of the esophagus?
- Mucosa
- Muscularis Mucosa
- Submucosa
- Muscularis Externa
- Adventitia or Serosa
What is the mucusa of the esophagus?
few mucous glands (in lamina propria)
What is the muscularis mucosa of the esophagus?
- increases in thickness along esophagus
- Sparse in upper esophagus ->complete layer in lower esophagus
- Upper eso: few fascilcles, lower: thin layer
What is the submucosa of the esophagus?
many mucous glands + b.v. + fibers (collagen+elastic)
blood vessels, collagen, elastic fibers
Where is muscularis externa located in the esophagus (3)? What type of muscle composes each part?
outer longitudinal + inner circular layers
- Upper esophagus = striated (skeletal) muscle
- Middle esophagus = striated (skeletal) + smooth muscle
- Lower esophagus = smooth muscle
Where is the adventita and serosa located in the esophagus?
- Adventitia = present in upper + middle esophagus
- Serosa = present in lower esophagus
What connects the esophagus to the stomach and how does the epithelium transition?
- Esophago-gastric junction
- Observe transition from stratified squamous -> to simple columnar epithelium
Where is an important site of common diseases like ulceration, barrett’s esophagus and cancer?
espophago/gastric jxn
What is the purpose of the Esophago-gastric junction?
- to prevent stomach acid (reflux) from reaching the esophagus
- B/c stomach acid would damage the stratified squamous epithelium of the esophagus
What does the reflux of gastric acid secretions into the lower esphagus cause?
- heartburn, inflammation and pain
- Leads to changes of the statified squamos epithium to a gastric type epithelium (simple columnar epithelium)-> metaplasia
What is barrett’s esophagus?
damage to the esophageal epithelium resulting in metaplasia
Barrett’s Esophagus
A. Cause
B. Result
C. Complication
D. Risk factors
A. Cause: long lasting reflux of stomach acid (heartburn)
B. Result: metaplasia = stratified squamous epithelium gets replaced w/simple columnar epithelium (i.e., gastric epithelium)
C. Complication: prone to ulceration + inflammation + esophageal cancer
D. Risk factors: alcohol + smoking
What type of epithelium is the stomach lined with?
Lined w/ simple columnar epithelium
Contains surface mucous cells (mucous cap) -> secrete mucous to protect the stomach lining from the stomach acid
What is ruga?
is a longitudinal fold of gastric muscosa and submuscosa
What is the organization of the stomach?
- Cardia (entrance) = connects to esophagus
- Fundus = top portion
- Body = middle portion
- Pylorus (exit) = bottom -near small intestine
What is gastric rugae and its fxn?
- folds of the gastric mucosa + submucosa
- allow for stomach to expand (i.e., increase surface area)
What are gastric glands and where do they extend from?
- exocrine glands in lamina propria (i.e., mucosa)
- Extend from the gastric pit which are invaginations of the epithelium
Name the 5 different cell populations of the gastric glands
- Mucous neck cells
- Parietal cells
- Chief cells
- Enteroendocrine cells
- Stem cells
“MPECS”
Mucous Neck Cells
A. Produce?
B. Lxn?
A. Produce: soluble mucous that lubricates the gastric contents
B. Lxn: near the lumen
Parietal cells
A. Produce?
B. Stain?
A. Produce: HCL + IF (intrinsic factor)
B. Stain:acidophilic
What is HCL production activated by?
activated by gastrin, histamine H2 + ACh
What is IF production necessary for?
IF production necessary for absorption of vitamin B12
Chief Cells
A. Produce
B. Stain
A. Produce: Pepsinogen + Lipase stored in granules
B. Stain: basophillic
Enteroendocrine cells
A. Produce
B. Release
A. Produce: gastrin, glucagon, serotonin, somatostatin
B. Release: hormones into the blood = endocrine fxn
Stem (Basal cells)
A. Produce and regenerate?
A. Produce and Regenerate the gastric cell population
What is H.Pylori and tx for it
- Helicobacter pylori = bacteria that invades epithelium of gastric mucosa -> destroys muscoa, epithelial cells, lamina propria die and ulcers are formed. Can also perforate the stomach wall and the gastric contents can pour into the peritoneal cavity-> death
- Tx: Anti-ulcer drugs: blockers of histamine H2 receptors (zantac) Proton pump inhibitors (omeprazole) and use of antibiotics
W/o surface mucous cells, the gastric epithelium is vulnerable to damage from the stomach acid
Results in destruction of the gastric mucosa -> which can lead to ulcers, atrophic gastritis, and stomach cancer
What is gastric ulcers and tx for it?
- Damage to the gastric epithelium (i.e., mucosa) from gastric acid leads to ulceration (openings in the epithelium of stomach)
- Tx: anti-ulcer drugs = histamine H2 receptor blocker (zantac) or proton pump inhibitors (omeprazole)
If the ulcer perforates the gastric wall -> gastric contents flood the abdominal cavity
What is atrophic gastritis?
Autoimmune atrophic gastritis results in damage to the gastric glands in the mucosa -> specifically the parietal cells
Gastrin hormone is secreted by what? location?
Secreted by G cells located in the gastric antrum
Histamine is produced by what? location?
Produced by Enterochromaffin-like cells neuroendocrine cells in the mucosa of gastric glands
B 12 deficity can lead to what?
CNS degeneration (demyelinization)
Atrophic gastritis and pernicious anemia with parietal cells present as what?
burning senation in soles of feet
