This document provides a summary for all information needed to pass the second partial exam of pathology.. It includes all lecture notes plus necessary information from the book. There are practice questions (including their answers)at the end of every chapter.
Lecture 7: gastrointestinal tract
ESOPHAGUS
Normal esophagus
Squamous epithelium!
Epithelium→ lamina propria→ mucosa
➔ Submucosa
➔ Smooth muscle
fibers
Obstructive diseases
- Mechanical obstruction: atresia is most common (atresia= when orifice in the body is
abnormally closed)→aspiration, suffocation
o Esophageal stenosis: narrowing of esophagus by thickening of submucosa due to
inflammation
- Functional obstruction
- Ectopia: displacement or malposition of esophagus
Vascular diseases
- Esophageal varices: enlarged veins due to obstructed portal blood flow→ results in
hypertension
Esophagitis: inflammation of the esophagus
Mallory Weiss tears: common tears in the esophageal wall caused by severe retching/vomiting
- Refluxing contents cause the wall to stretch and tear
Reflux esophagitis
- When (long term) the acidic contents of the stomach go up the esophagus (squamous
epithelium cannot handle this)
- Phase 1: inflammation
o Hyperemia, granulocytes (in severe cases
ulceration)
- Phase 2: metaplasia and chronic inflammation
,Barrett esophagus
- Complication of chronic GERD,
characterized by intestinal
metaplasia
o Intestinal metaplasia
▪ Squamous cells of
esophagus are
replaced with
intestinal type
epithelium
• Glandular structures
Cancer
Development of esophageal carcinoma (reminder: carcinoma= malignant cancer arising in epithelial
tissue/lining of organs)
1. Esophagitis→ intestinal metaplasia→ dysplasia→adenocarcinoma (Barrett carcinoma)
2. Dysplasia→ squamous cell carcinoma
Adenocarcinoma (Barrett carcinoma): neoplasia of epithelial tissue with gland-like pattern, arises after
long term gastroesophageal reflux disease (GERD)
Squamous cell carcinoma: associated with alcohol and tobacco use and poverty
Adenocarcinoma in esophagus is more common than the squamous cell carcinoma
- You would think that because the esophagus has squamous epithelium, the squamous cell
carcinoma would have a higher prevalence.
- However, due to intestinal metaplasia as a precursor for the adenocarcinoma, the
adenocarcinoma has a higher prevalence
Esophageal carcinoma: predisposing factors
- Squamous cell carcinoma
o Smoking
o Alcohol
o Achalasia
o Stricture
- Adenocarcinoma
o Reflux esophagitis
o Intestinal metaplasia
,Dysplasia: presence of abnormal cells within a tissue/organ
(precursor of cancer)
- If inflammation continues molecular changes can occur
- Changes in morphology
- Cytonuclear atypia
o Large nuclei
o Irregular shape of nuclei
o Coarse chromatin pattern
Dysplasia of squamous epithelium
- Right picture: large nuclei and not a lot of differentiation
- As long as it’s not invading→dysplasia (and not carcinoma)
When it starts to invade→ squamous cell carcinoma
- Areas of tumor cells (blueish) infiltrate in deeper walls of the esophagus
STOMACH
Normal stomach
, Anatomy of the stomach: 4 main regions
- Cardia
o Lined by mainly foveolar cells (mucin secreting) that form shallow
glands
- Fundus
o Parietal cells
o Cells contain chief cells (produce and secrete digestive enzymes)
- Body
o Parietal cells
o Cells contain chief cells (produce and secrete digestive enzymes)
- Antrum (part of pylorus which connects to the body of the stomach)
o Glands contain endocrine cells (G cells)
Gastric mucosa
- Foveolar layer: mucus production
- Glandular layer consists of multiple cell types
- Smooth muscle: muscularis mucosae
Histology of the body (of the stomach)
- 2 most important types of cells in corpus part of the stomach
o Parietal cells (pink in histology picture)
▪ Acid production
▪ Intrinsic factor production
• Important protein
• Binds to vitamin B12
• Without intrinsic
factor→ no intake B12
o Chief cells (blue in histology picture)
▪ Pepsinogen production
• Protein important for
digestion of food
• Breaks up into smaller molecules when in contact with acid fluid in
stomach
Histology antrum of stomach: lower part of the stomach
- Same foveolar lining as corpus
- Glandular layer differs
o Cells more pale
o No parietal and chief cells
o More mucus producing cells with
antibacterial functions
o Hormone producing cells
▪ Hard to point out in histological
slide
▪ Important one: gastrin
• Protein that stimulates production of acidic fluid by parietal cells
Gastritis: inflammation of the gastric mucosa
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