GI Tract: Stomach Flashcards
What is the general organization of layers of the GI Tract?
Mucosa
- Epithelium
- Lamina Propria
- Muscularis Mucosae
Submucosa
Muscularis Externa (2 smooth muscle layers, 3 for stomach)
Adventitia
What kind of epithelium would you find in the Pharynx?
Nasopharynx: Respiratory Epithelium (ciliated Pseudostratified Columnar)
Oropharynx: Strat. Squamous, Non-keratinized/Para-keratinized**
What is the radial organization of the Esophagus?
From Innermost to Outermost:
- Mucosa
- Muscularis Mucosa
- Submucosal Plexus (Meissner’s Plexus)
- Submucosa
- Circular Muscle
- Myenteric Plexus (Auerbach’s Plexus)
- Longitudinal Muscle
- Serosa
What are the Cardiac Glands in the Esophagus?
They are mucous producing esophageal glands located in the Lamina Propria of the terminal part of the esophagus (Esophago-gastric junction).
Note that this is the only place in the GI tract that has submucosal mucous glands, aside from in the duodenum.
What is the function of Meissner’s plexus?
Secretion for ease of swallowing/protection(?)
What is the function of Auerbach’s plexus?
Myenteric plexus; innervates the muscularis externa.
Is responsible for inducing peristalsis
Describe the muscle states during Peristalsis.
Above the bolus of food:
- Relaxed Muscles above the bolus
- Circular Muscles directly above the bolus to push it down the eophagus.
Below the bolus of food:
- longitudinal muscles contract
Circular muscle contraction pushes bolus further down, and muscle layers will relax when bolus passes their level.
What is a tell-tale sign that you are looking at the Esophagus?
Para-keratinized Stratified Squamous Epithelium.
Giveaway trait is the presence of nuclei in the keratin layer, as well as the protrusion of the nuclei into the lumen of the Esophagus.
What is present in the Esophago-Gastric Junction, and what is its function?
Cardiac Glands of esophagus. They neutralize the acid of the stomach to prevent acid from damaging the esophageal epithelium.
What is Barrett’s Esophagus?
Tissue lining that replaces normal esophageal lining due to gastric acid (GERD).
The process of Barrett’s Esophagus forming is called Intestinal Metaplasia.
Risk of Esophageal Cancer increases.
What are the four regions of the Stomach?
Fundus, Corpus, Antrum, Pylorus.
What are rugae?
Irregular folds in the mucosa/submucosa. Appear when stomach is empty/contracted, disappear when stomach is full/distended.
What are the gastric pits?
AKA Foveolae gastricae.
They contain glands that add mucus, acid, and pepsin.
Describe the organization of the layers of the Stomach.
Mucosa
- Epithelium (Coumnar epithelial with Surface mucous cells at apex)
- Lamina Propria (filled with gastric pits and glands)
- Muscularis Mucosae (help empty glands)
Submucosa
Muscularis Externa (THREE layers)
- Outer Longitudinal
- Middle Circular
- Inner Oblique
Serosa
What is the function of the Surface Mucous Cells? Are they found anywhere else?
They secrete mucus for protection of the Stomach lining. They are also found inside the gastric pits, and are called Neck mucous cells (function is the same).
