Anatomy of Stomach's Mucosa

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Questions and Answers

What percentage of the gastric gland area do fundus and body regions comprise?

50%

Less than 5%

75% (correct)

25%

What type of cells are responsible for secreting gastrin in pyloric glands?

G cells (correct)

Chief cells

Parietal cells

Mucous neck cells

What is the primary function of the rugae in the stomach?

To facilitate digestion

To accommodate expansion and filling of the stomach (correct)

To absorb nutrients

To produce mucinogen granules

What is the function of stem cells in the gastric glands?

To proliferate and give rise to other gastric epithelial cells Signup and view all the answers

What is the main difference between mucous neck cells and surface mucous cells?

The type of glycoproteins they produce Signup and view all the answers

What is the structure composed of the mucosa and underlying submucosa?

Rugae Signup and view all the answers

What is the name of the portion of the stomach where the pylorus is located?

Pyloric portion Signup and view all the answers

What is the main function of parietal cells in the gastric glands?

To secrete HCl and intrinsic factor Signup and view all the answers

What is the characteristic of the simple columnar epithelium in the mucosa?

It has a large, apical cup of mucinogen granules Signup and view all the answers

What type of cells are present in cardiac glands?

Mucous and endocrine cells Signup and view all the answers

What is the function of the mucous cup in the surface mucous cells?

To create a glandular sheet of cells Signup and view all the answers

What is the primary function of the golgi stacks in mucous cells?

To transport glycoproteins Signup and view all the answers

What is the layer of muscles in the stomach wall that is not present in other parts of the gastrointestinal tract?

Oblique layer Signup and view all the answers

What is the characteristic feature of the apical surface of surface mucous cells?

Mucous granules Signup and view all the answers

What is the location of the gastric pits in the stomach?

In the mucosa Signup and view all the answers

What happens to the rugae when the stomach is fully distended?

They virtually disappear Signup and view all the answers

Chief cells are characterized by an abundance of what in the basal cell region?

Rough Endoplasmic Reticulum (RER) Signup and view all the answers

What is the function of the apical membrane in chief cells?

Secretion of zymogen granules Signup and view all the answers

What is the shape of chief cells?

Pyramidal or oval Signup and view all the answers

What is the function of carbonic anhydrase in parietal cells?

Conversion of H2O and CO2 to H+ and HCO3- Signup and view all the answers

What energizes the acid secretion process in parietal cells?

Mitochondria Signup and view all the answers

What are the three major activators of HCl production by parietal cells?

Gastrin, histamine, and acetylcholine Signup and view all the answers

What is the function of intrinsic factor produced by parietal cells?

Absorption of vitamin B12 Signup and view all the answers

What disease is caused by a lack of vitamin B12?

Pernicious anemia Signup and view all the answers

What type of cells are found in pyloric glands?

Gastrin cells, mucous cells, parietal cells, and other endocrine cells Signup and view all the answers

What is the function of gastrin secreted into the blood?

Stimulates acid secretion by parietal cells Signup and view all the answers

What inhibits COX, an enzyme for prostaglandin synthesis?

NSAIDs Signup and view all the answers

Which hormone inhibits gastric HCl production by acting on G cells and ECL cells?

Somatostatin Signup and view all the answers

What acts directly on parietal cells to inhibit HCl production?

Prostaglandins and GIP Signup and view all the answers

Which of the following is NOT a major determinant of gastric acid secretion?

Insulin Signup and view all the answers

What is the function of urogastrone (epidermal growth factor)?

Inhibits HCl production by parietal cells Signup and view all the answers

What is the role of surface epithelium in the stomach?

Produces mucus to protect itself from HCl and pepsin Signup and view all the answers

What is the main function of the small intestine?

Digestion and absorption of nutrients Signup and view all the answers

What is the name of the junction where the ileum meets the cecum?

Ileocecal junction Signup and view all the answers

What is the function of the enzymes located in the glycocalyx of the microvilli?

To complete the breakdown of sugars and proteins Signup and view all the answers

What is the name of the folds in the submucosa that increase the absorption surface of the small intestine?

Plicae circulares Signup and view all the answers

What type of cells are responsible for absorbing basic food components in the small intestine?

Enterocytes Signup and view all the answers

What is the name of the thin layer visible in the light microscope that is composed of microvilli?

Brush border Signup and view all the answers

What is the approximate length of the ileum?

3.5 m Signup and view all the answers

How many main cell types are present in the intestinal epithelium?

7 Signup and view all the answers

Study Notes

Stomach Anatomy

The stomach has three histological structures: cardiac portion, fundus, and pylorus.
The inner surface of the empty stomach has longitudinal folds called rugae, which disappear when the stomach is fully distended.

Stomach Wall Layers

The stomach wall has several layers: mucosa, submucosa, and muscularis externa, with an additional oblique layer of muscles in the stomach.
The mucosa has simple columnar epithelium with surface mucous cells containing a large, apical cup of mucinogen granules.
The mucosa also has five different cell types: mucous neck cells, chief cells, parietal cells (also called oxyntic cells), enteroendocrine cells (DNES), and stem cells.

Fundic Glands

Fundic glands are composed of parietal, chief, mucous neck, DNES, and stem cells.
They are responsible for HCl, pepsinogen, and intrinsic factor secretion.
Parietal cells produce HCl, which is an active transport process requiring significant ATP.
Parietal cells also produce intrinsic factor, a glycoprotein necessary for the jejunal absorption of vitamin B12.

Pyloric Glands

Pyloric glands contain mucous, some parietal, and endocrine cells, including G cells that secrete gastrin.
Gastrin secreted into the blood stimulates acid secretion by parietal cells of fundic glands.

Regulation of Gastric Acid Secretion

The three major activators of HCl production by parietal cells are: acetylcholine, histamine, and gastrin.
Inhibitors of gastric acid secretion include: somatostatin, prostaglandins, and gastric inhibitory peptide (GIP).

Small Intestine

The small intestine is the principal site for the digestion and absorption of food.
The small intestine has structures that increase the absorption surface: plicae circulares, villi, and microvilli.
There are 7 main cell types in the intestinal epithelium: enterocytes, goblet cells, Paneth cells, enteroendocrine cells, M cells, stem cells, and lymphocytes.

Enterocytes

Enterocytes are resorptive cells that take up basic food components: simple sugars, amino acids, pyrimidines and purines, glycerol, and fatty acids.
They are tall columnar cells with numerous mitochondria, abundant SER, RER, and Golgi complex, and many endocytotic vesicles.

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Description

This quiz covers the histological structures of stomach's mucosa, including the cardiac portion, fundus, body, and pylorus. Learn about the different parts of the stomach and their functions.