39. Histology - Microanatomy of the Stomach & Esophagus

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Questions and Answers

Which layer of the esophagus is primarily responsible for peristaltic movement?

Adventitia

Muscularis externa (correct)

Submucosa

Mucosa

Which type of glands are primarily found in the gastric mucosa of the stomach?

Cardiac glands

Pyloric glands

Gastric (fundic) glands (correct)

Salivary glands

What characterizes the transition region between the esophagus and stomach?

Absence of submucosa

Change from stratified squamous to simple columnar epithelium (correct)

Presence of serosa

Increase in the muscularis mucosa

Which cell type in the gastric glands is primarily responsible for the secretion of hydrochloric acid?

Parietal cells Signup and view all the answers

What is the main function of enteroendocrine cells found in the gastric glands?

Secretion of hormones like gastrin Signup and view all the answers

Which feature distinguishes the muscularis externa of the stomach from that of other sections of the gastrointestinal tract?

Three distinct layers of muscle Signup and view all the answers

What type of epithelium lines the surface of the stomach mucosa?

Simple columnar epithelium Signup and view all the answers

Which of the following layers of the alimentary canal contains the enteric nervous system?

Submucosa Signup and view all the answers

What is the primary function of the muscularis mucosae in the gastrointestinal tract?

To facilitate changes in surface area for secretion and absorption Signup and view all the answers

Which statement accurately describes the composition of the submucosa?

It consists of dense irregular connective tissue with vessels and nerves Signup and view all the answers

What is the difference between the muscularis externa of the esophagus and that of the stomach?

The stomach has an additional inner oblique muscle layer Signup and view all the answers

What is the role of the myenteric plexus within the muscularis externa?

It coordinates peristalsis and other muscle contractions Signup and view all the answers

Which component is NOT found in the submucosa of the gastrointestinal tract?

Glands Signup and view all the answers

At which points in the gastrointestinal tract does skeletal muscle appear in the muscularis externa?

Only at the ends of the esophagus and anal canal Signup and view all the answers

What are the two main muscle layers found in the muscularis externa?

Longitudinal and circular Signup and view all the answers

The ganglion cells of which plexus are located in the submucosa?

Meissner's plexus Signup and view all the answers

What role do intracellular canaliculi play in parietal cells?

They are involved in increasing the cell's surface area. Signup and view all the answers

What enzyme is crucial for the formation of hydrogen ions in parietal cells?

Carbonic anhydrase Signup and view all the answers

Which mechanism is primarily responsible for the release of hydrogen ions in active parietal cells?

Fusing of tubulovesicular membranes with the plasma membrane. Signup and view all the answers

What is the primary appearance of cells containing abundant mitochondria?

Acidophilic appearance resulting from metabolic activity. Signup and view all the answers

What ions are primarily involved in the formation of hydrochloric acid in parietal cells?

H+ and Cl- Signup and view all the answers

How do bicarbonate ions form in parietal cells?

Through the action of carbonic anhydrase. Signup and view all the answers

Which cellular component is primarily involved in the transport of ions in parietal cells?

Intracellular canaliculi Signup and view all the answers

What happens to the tubulovesicular membranes in parietal cells when the cell is active?

They fuse with the plasma membrane. Signup and view all the answers

What concurrent substances are released into the lamina propria?

HCO3- and K+ Signup and view all the answers

What significant change occurs in inactive parietal cells?

Increase in cytoplasmic tubulovesicular membrane system Signup and view all the answers

Which of the following statements about gastric intrinsic factor (GIF) is accurate?

It is a glycoprotein necessary for vitamin B12 absorption. Signup and view all the answers

Where are chief cells primarily located?

Base of the glands Signup and view all the answers

What structural component is characteristic of chief cells?

Prominent Golgi complexes Signup and view all the answers

Which secretion is primarily associated with chief cells?

Pepsinogen Signup and view all the answers

What is the main function of the tubulovesicular membrane system in parietal cells?

Contributing to gastric acid secretion Signup and view all the answers

Which of the following correctly describes basophilic cells?

They are typically found in the lower part of gastric glands. Signup and view all the answers

How do cardiac glands primarily differ from gastric glands in terms of cellular composition?

Cardiac glands contain mainly mucous cells. Signup and view all the answers

Which feature distinguishes pyloric glands from cardiac glands?

Pyloric glands possess a thicker mucosa. Signup and view all the answers

What is a notable structural characteristic of pyloric glands relative to gastric glands?

Pyloric glands feature much longer gastric pits. Signup and view all the answers

When comparing the mucosal structure of cardiac glands with that of pyloric glands, which statement is accurate?

The mucosa of cardiac glands contains less lymphatic tissue than that of pyloric glands. Signup and view all the answers

Which of the following statements accurately describes the staining characteristics of cardiac and pyloric glands?

Neither cardiac nor pyloric glands exhibit a striped staining appearance. Signup and view all the answers

Which gland type is more likely to contain significant amounts of lymphatic tissue in its lamina propria?

Pyloric glands Signup and view all the answers

In the context of compared dimensions, which feature is true regarding pyloric glands?

Pyloric glands possess longer gastric pits and thicker mucosa than gastric glands. Signup and view all the answers

What distinguishes the mucous cells in cardiac glands from those in gastric glands?

Mucous cells in cardiac glands exhibit no striped staining appearance. Signup and view all the answers

Study Notes

Esophagus and Stomach Microanatomy

Alimentary Canal
- Layers
  - Mucosa: innermost layer, lines the lumen, composed of epithelium, lamina propria, and muscularis mucosae
  - Submucosa: beneath mucosa, connective tissue, contains blood vessels, lymphatics, and nerves
  - Muscularis Externa: smooth muscle, usually two layers: inner circular and outer longitudinal
  - Serosa/Adventitia: outermost layer, composed of epithelial lining with connective tissue (serosa) or connective tissue only (adventitia)
- Enteric Nervous System: controls digestive functions; includes submucosal (Meissner's) plexus and myenteric (Auerbach's) plexus
Esophagus
- Function: transports food from mouth to stomach
- Layers:
  - Mucosa: nonkeratinized stratified squamous epithelium, lamina propria, muscularis mucosae
  - Submucosa: dense connective tissue, contains esophageal glands
  - Muscularis Externa: two layers (inner circular and outer longitudinal), composed of smooth muscle in middle portion, skeletal muscle at beginning and end
Stomach
- Function: mechanical and chemical breakdown of food
- Layers:
  - Mucosa: simple columnar epithelium, lamina propria, muscularis mucosae
    - Gastric Pits: invaginations of epithelium, lead to gastric glands
    - Gastric Glands: produce gastric juice
      - Chief cells: produce pepsinogen (inactive enzyme) and gastric lipase
      - Parietal cells: produce HCl and intrinsic factor
      - Mucous cells: secrete mucus
      - Enteroendocrine cells: produce hormones like gastrin, somatostatin, and histamine
  - Submucosa: dense connective tissue, contains blood vessels, lymphatics, and nerves
  - Muscularis Externa: three layers (inner oblique, middle circular, outer longitudinal), all smooth muscle

Stomach Glands

Gastric (Fundic) Glands:
- Occupy most of the stomach
- Parietal Cells:
  - Produce HCl: essential for digestion, and also produce intrinsic factor (GIF) which is crucial for absorbing vitamin B12. - Acidophilic appearance due to abundant mitochondria
- Chief Cells:
  - Produce inactive pepsinogen, which is activated to pepsin in the acidic environment of the stomach.
  - Basophilic appearance due to abundant ribosomes associated with the rough endoplasmic reticulum (rER).
Cardiac Glands:
- Located in the cardia (upper part of stomach)
- Primarily contain mucous cells, no striped staining appearance
Pyloric Glands:
- Located in the pylorus (lower part of stomach)
- Primarily contain mucous cells, longer gastric pits and overall thicker mucosa than cardiac glands
- Abundant lymphoid tissue present in lamina propria

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Description

Test your knowledge on the microanatomy of the esophagus and stomach with this detailed quiz. Explore the various layers of the alimentary canal, the enteric nervous system, and their functions. Perfect for students of anatomy and physiology.