3. Histology Flashcards
• Only two segments of the GI tract that contain submucosal glands > ____ (lower 1/3), or the ____ of the SI
○ Nowhere else you will find submucosal glands
esophagus
duodenum
General Organization of the GI Tract
- Mucosa:
- Three components:
- Lining: ____. May show specialized structures.
- Lamina propria: Loose ____tissue.
- Muscularis mucosae: ____ muscle.
- Other structures:
- Lymphatic nodules:
- ____.
- ____ intestines.
- Secretory glands:
- Mucosal: extending into the ____.
- Submucosal: extending into the ____.• Mucosa made up of three componentsn:
○ Epithelium
§ May or may not show specialized structures
○ LP
§ Not always present in every organ
○ Muscularis
§ May or may not be there in all the sections
• Embedded in the mcuosa and dpeneidng on which section of tract: may find LM or SG
epithelium connective smooth lamina propria small and large lamina propria submucosa
General Organization of the GI Tract
- Submucosa:
- Dense ____ connective tissue.
- Large blood vessels, lymphatics and nerves branching into mucosa and submucosa.
- Glands only in ____ and ____.
- Muscularis:
- Smooth muscle:
- Inner layer: ____.
- Outer layer: ____.
- Skeletal muscle:
- Only in ____ and anal sphincter.
- Adventitia:
- Connective tissue.
- May be covered by a ____(simple squamous epithelium) + thin CT layer forming a ____ (serous membrane).
irregular
esophagus
duodenum
circular
longitudinal
upper esophagus
mesothelium
serosa
- The Esophagus
• Functions:
• Propels swallowed food from oral cavity to
stomach.
• Layers:
- Mucosa: ____ folds.
- Epithelium: ____ squamous.
- Lamina propria: CT.
- ____glands.
- Muscularis mucosae:
- ONLY present near the ____.
- Submucosa: CT.
- Submucosal glands: ____ (mucins) and ____ (lysozyme).
• Muscularis: • Two layers: \_\_\_\_ and longitudinal. • Upper third: \_\_\_\_ muscle. • Middle third: \_\_\_\_ muscles. • Lower third: \_\_\_\_ muscle.
longitudinal
stratified non-keratinizing
cardiac esophageal
stomach
mucous serous circular striated (skeletal) striated and smooth smooth
• Mucosa is SSE that is non-keratinized ○ From \_\_\_\_ to \_\_\_\_ (stomach) ○ Constant • At LP ○ In cardial region (lower segment around the stomach, above the LES), the only place you find the cardiac esophageal glands § More abundant in this are § One half down • Submucosa ○ Distinct structure: in the lower 1/3 § Unusual in the GI tract § Produce mucins □ Mucus that covers and protects esophagus and stomach □ Lysozyme - \_\_\_\_ • Muscularis ○ Depending on where we're looking - will be composed of skeletal or smooth muscle § Inner: circular § Outer: longitudinal § Upper 1/3: skeletal § Middle 1/3: skeletal and smooth § Lower: 1/3 smooth ○ Tells you how the esophagus works § Upper part - innervated by \_\_\_\_ fibers □ This area is still controlled during \_\_\_\_ § Once food into the esophagus - the movement that pushes it down > \_\_\_\_ - through the creation of peristaltic movmements - autonomic innervation of smooth muscle
upper sphincter lower sphincter antibacterials voluntary swallowing involuntary
The esophagus
• Longitudinal folds ○ \_\_\_\_ and \_\_\_\_ are invaginated • At mucosa - can see the SSE lining the lumen • Can see secretory glands in the submucosa ○ Lower \_\_\_\_ of the esophagus
mucosa
submucosa
third
The esophagus
• \_\_\_\_ separates the submucosa and the mucosa ○ Denotes that it's closer to to the \_\_\_\_ • Reason for the SSE - the esophagus is in contact with rough material ○ Continuously regenerating layers of new cells - protects the underlying mucosa
muscularis mucosae
stomach
GEJ
Mucosa of esophagus vs. stomach
• Upper: ____ - correpsondign to the esophagus
• Down: secretory epithelium with ____ and glands that’s part of the stomac
○ Highly secretory
SSE
gastric pits
- The Stomach
• Functions:
• Homogenization and chemical processing of
the swallowed semisolid food.
• Four regions:
1. ____: surrounds the esophageal opening.
2. ____: to the left of the esophageal opening.
3. ____: central region.
4. ____: extending to the gastroduodenal orifice.
cardia
fundus
body
antrum
The Stomach
• Epithelium: ____ epithelium.
• Lamina propria:
• Loose CT.
• Surrounds the cardiac, gastric, and pyloric ____.
• Muscularis mucosae: ____ fibers, some project into the ____ to induce
gland secretions.
- Submucosa:
- Dense ____ CT.
- ____
- Submucosal plexus of ____.
- Muscularis:
- Three layers of smooth muscle: ____, ____, and ____.
- ____ plexus of Auerbach.
The Stomach
• The epithelium is secretory
• The muscualrisu is made up of smooth muscle fibers
○ Three layers: you now have an oblique layer
§ Where you find the myenteric plexus of auerbach
secretory columnar simple
glands
smooth muscles
mucosa
irregular
lymphatics
meissner
circular
oblique
transverse
myenteric
The Stomach: Gastric Mucosa
• L: SEM showing wall of stomach ○ Rugae § Find what you see on the right side § Invaginations of the \_\_\_\_ and \_\_\_\_ of the wall of the stomach □ \_\_\_\_ contains the gastric glands ® Pits are tops of conduits that reach the sruface of the stomach § Thick mucosa - due to the environement § Highly secretory □ Produce \_\_\_\_ and \_\_\_\_ and \_\_\_\_
mucosa submucosa mucus HCl pepsinogen
The Cardia Region of the Stomach
• Secretory mucosa
○ Find gastric glands that are____ and form a ____ tube that ends in the pit at the surface of the soamtch
○ The glands are highly ____ (extend the longitude of the galnd itself without penetrating thorugh the muscularis mucosae)
§ Look at these glands in LM picture > box area > coiled ends produce copmlex morphology where you cannot follow a gland from the pit to the ____
□ Explains why most mucosa is occupied by the coils formed by the ____
□ Gastric glands are formed by secretory cells that produce ____
® Not different from those found outside the gland on the epithleium of the ____ at this elevel
® Produce mostly ____
simple single coiled conduit gastric glands mucus stomach mucus
Fundus-Body Region of the Stomach: Gastric Glands
- Very abundant: 15 million.
- Gastric gland regions:
- ____
- ____
- ____• Main region In terms of secretory function > ____ region combined
• A large number of gastric glands
○ Are different from those in the ____region
○ Tubular glands
§ Combined into ____+ tubes that end at surfcae of stomach at a single pit/faveola
§ Most complex gastric glands
§ The glands are divided into:
□ Pit
□ Neck
□ Body
® Different ____ are found in each region
pit neck body fundus/body cardia two cells
Fundus-Body Region of the Stomach: Gastric Glands
• Very abundant: 15 million.
• Gastric gland regions:
• Pit: surface ____cells.
• Neck: ____ cells, stem cells, and ____ cells.
• Body: ____ cells, chief cells, ____ cells.
• Pit ○ Gland connects with surface of \_\_\_\_ ○ Surface mucous cells § Same cells found outside of the gland lining the epithelium of the body of the stomach • Neck ○ Richer population is located ○ Mucous neck cells § Different from surface cells • Body ○ Depending on the region will find different cell populations
mucous mucous neck parietal parietal enteroendocrine stomach
Fundus-Body Region of the Stomach: Gastric Glands
• At \_\_\_\_ of the gland near the surface of the stomach ○ Secretory cells that are similar to \_\_\_\_ (morphologically slightly different) § These cells are secretory for \_\_\_\_ § Involved in \_\_\_\_ in the wall of the stomach □ From the HCl that is produced in deeper regions of the gastric gland
pit
goblet cells
mucus
protection
Fundus-Body Region of the Stomach: Gastric Glands
• Reach neck of the gland ○ Mucous neckc ells § Different from the ones found at the \_\_\_\_ § Don't just recognize the morphology § In the neck, find cells that produce \_\_\_\_ anda re \_\_\_\_
pit
mucus
secretory
Fundus-Body Region of the Stomach: Gastric Glands
• Upper and lower regions of the body of the gland is where it's interesting • Start to find specialized populations fo cells ○ Parietal cell § Produce \_\_\_\_l § \_\_\_\_ § \_\_\_\_ stain § \_\_\_\_ nucleus § Remember where they're located and what they do
HCl
secretory
pale
central
Fundus-Body Region of the Stomach: Gastric Glands
• Body of the gastric gland ○ In the lower region: chief cells § \_\_\_\_ staining (nuclei are basal) § \_\_\_\_ stain in the apical domain > produce \_\_\_\_ □ Deep red stain is bc of the secretory granules that stain well □ Less pale than the parietal cells ○ Will also find \_\_\_\_ cells (D cells) § Respond to the presence of \_\_\_\_s in the chyme (digestive mix) and respond to the \_\_\_\_ produced by the secretion of HCl § Release hormones into the BS > regulate the secretion of these same glands □ Hormone = gastrin
basophilic dark pepsinogen enteroendocrine proteins HCl
Fundus-Body Region of the Stomach: Gastric Glands
• Exocrine glands - major of the stomach • Parietal cell ○ Produces HCl ○ Produce \_\_\_\_ § Required for absorption of vitamin B12 and internalize them § Binds to B12 • Chief cells ○ Produce pepsinogen § Inactive - \_\_\_\_ form of the enzyme, pepsin (a protease) § Starts the degradation of proteins at level of the stomach • Compare the morphology ○ Parietal § \_\_\_\_ cells § Cytoplasm is firstly \_\_\_\_, and out of the invagination > some cytoplasmic processes > smaller degree of invaginations are prodcued > \_\_\_\_ □ By increasing the secretory surface of the cell > ensure high rate of \_\_\_\_ secretion and production □ To increase the secretory surface § Rich in \_\_\_\_ □ Require a lot of energy to pump Cl and protons to form HCl ® A lot of ion trafficking bt the interstitium and basal domain of the cell ® Also pumping at the level of the canaliculi ○ Chief cells § Very different morphology! § Nucleus pushed to \_\_\_\_ domain § Apical domain is characterized by presence of secreotyr garnules □ Zymogen - pepsinogen □ Stained very \_\_\_\_
IF zymogen pale invaginated secretory canaliculi HCl mitochondria basal darkly
Pyloric Region of the Stomach
• Also find \_\_\_\_ glands ○ Complex glands: \_\_\_\_+ branches of secretory tubules that converts into a s ginle secretory duct > ends in a single \_\_\_\_ • Pyloric glands ○ Lined by secretory cells that produce mucus ○ No parietal, chief or NE cells • Thick mucosa • Deep pit lined by secretory cells that produce mucus • Structure of gland is different ○ Much \_\_\_\_ into the tissue ○ Down to where the \_\_\_\_ are joined
secretory three pit deeper secretory glands
