Stomach Disorders: A&P

Question 1

What are the 4 layers of the stomach and what is the main function of each?

Answer 1

• Mucosa
  
  • Produce digestive enzymes
  • Produce protective enzymes for the stomach lining
• Submucosa
  
  • Blood vessel layer
  • Perfusion
• • Muscularis
  
  • Provides for peristaltic activity
• • Serosa
  
  • Connective tissue forming that outer layer of the stomach

Question 2

What is the purpose of stomach rugae?

Answer 2

• Provide large surface area for stretching of stomach

Question 3

What are the 4 gastric glands/cells of the mucosa layer?

Answer 3

• Mucous cells
• Zymogenic cells (aka. chief cells)
• Parietal cells
• Endocrine cells

Question 4

What do the mucous cells secrete?

Answer 4

• An alkaline mucus that protects the epithelium against shear stress and acid

Question 5

What do the chief cells secrete?

Answer 5

• Pepsinogen which is converted to Pepsin by the HCl (low pH) of the stomach

Question 6

What is Pepsin?

Answer 6

• Stomach enzyme that serves to digest proteins found in ingested food

Question 7

What do the parietal cells secrete?

Answer 7

• Hydrochloric acid and
• Intrinsic factor

Question 8

What is the purpose of stomach HCl?

Answer 8

• Break down ingested food as part of the digestive system
• Kills bacteria as part of the immune system

Question 9

What is the purpose of the intrinsic factor released by parietal cells?

Answer 9

• The intrinsic factor plays a crucial role in the transportation and absorption of the vital micronutrient vitamin B12 (cobalamin, Cbl) by the terminal ileum (end of the small intestine)

Question 10

What happens if the intrinsic factor of parietal cells is not released?

Answer 10

• The body will not be able to absorb Vitamin B12

Question 11

What is the importance of vitamin B12?

Answer 11

• It is necessary for both the production of red blood cells and for the utilization of iron
• Lack of B12 will lead to anemia

Question 12

What are the two “gateways” into and out of the stomach?

Answer 12

• Cardiac valve through which food passes from the esophagus into the stomach
• Pyloric valve through which chyme passes out of the stomach and into the duodenum

Question 13

What are the two types of endocrine cells of the stomach and what does each secrete?

Answer 13

• G cells: secrete gastrin
• D cells: secrete somatostatin

Question 14

What does Gastrin do?

Answer 14

• Gastrin helps the pancreas produce enzymes for digestion and helps the liver produce bile.
• It triggers parietal cells to produce HCl
• It stimulates the intestines to help move food through the digestive tract

Question 15

What is Somatostatin and what does it do?

Answer 15

• It is an inhibitory hormone that reduces gastric secretion, gastrointestinal motility and to inhibit the secretion of gastrointestinal hormones, including gastrin and secretin.

Question 16

Gastrin and somatostatin work together to…

Answer 16

• Regulate the digestive system

Question 17

What three areas of the body does somatostatin affect?

Answer 17

• Anterior pituitary
• Pancreas
• Gastrointestinal system

Question 18

How does somatostatin affect the anterior pituitary gland?

Answer 18

• Inhibits the release of growth hormone
• Inhibits the release of thyroid stimulating hormone

Question 19

How does somatostatin affect the pancreas?

Answer 19

• Cells within pancreatic islets secrete insulin, glucagon, and somatostatin.
• Somatostatins inhibit the secretion of both insulin and glucagon

Question 20

How does somatostatin affect the gastrointestinal system?

Answer 20

• Suppresses the release of GI hormones (such as gastrin)
• Decreases rate of gastric emptying and reduces smooth muscle contractions (peristalsis)
• Suppresses the release of pancreatic hormones (insulin, Glucagan)
• Slows down the emptying of the stomach and bowel

Question 21

Name 3 somatostatin medications.

Answer 21

• Octreotide (Sandostatin)
• Lanreotide (Somatuline)
• Pasireotide (Signifor)