Alimentary system

Question 1

What are the layers of the GI tract walls?

Answer 1

• Mocosa
• Submucosa
• Muscularis propria
• Adventitia

Question 2

What are the layers of the GI tract mucosa?

Answer 2

1. Epithelium
2. Lamina propria
3. Muscularis mucosae

Question 3

What is the submucosa?

Answer 3

Layer of supporting tissue containing:

• Blood vessels
• Nerves
• Lymphatics

Question 4

What are the layers of the muscularis propria?

Answer 4

1. Circular smooth muscle layer (inner)
2. Longitudinal smooth muscle layer (outer)

Question 5

What is the adventitia?

Answer 5

Layer of supporting tissue containing:

• Blood vessels
• Nerves

It is called the serosa in the abdomen

Question 6

What type of epithelia line the oesophagus?

Answer 6

Stratified squamous epithelium (sometimes keratinised)

Question 7

What types of glands are found in the stomach?

Answer 7

• Oxyntic glands (body + fundus)
• Cardiac glands (cardia)
• Pyloric glands (pylorus)

Question 8

What types of glands are found in the stomach?

Answer 8

• Cardiac glands: Found in cardia and secretes mucous but does not contain acid-secreting cells.
• Oxyntic glands: Found in the fundus and body of the stomach and contain:
  1. Parietal cells
  2. Chief cells
  3. Mucous-secreting cells
  4. Endocrine cells
• Pyloric glands: Found in the antrum of the stomach and conain:
  1. Mucous-secreting cells
  2. G-cells

Question 9

What are the differences between gastric glands and cardiac/pyloric glands?

Answer 9

• Gastric glands contain parietal (oxyntic) cells and peptic (chief) cells, as well as mucous secreting cells.
• Cardiac/pyloric gands contain mostly mucous secreting cells.

Question 10

What are the cells found in gastric glands?

Answer 10

1. Mucous-secreting cells
2. Parietal cells
3. Peptic cells

Question 11

What are the shapes of cells in the gastric glands?

Answer 11

• Mucous-secreting cells: Columnar
• Parietal cells: Central nucleus, ‘fried egg’ shaped
• Peptic cells: Basophilic cytoplasm, basally located nuclei

Question 12

What are the different types of mucous-secreting cells?

Answer 12

1. Surface mucous cells
2. Neck mucous cells

Question 13

What is the function of parietal cells?

Answer 13

Secretes:

• HCl
• Intrinsic factor

Question 14

What is the function of peptic cells?

Answer 14

Secretes pepsinogens

Question 15

What is special about the duodenum?

Answer 15

It contains Brunner’s glands

Question 16

What is the function of Brunner’s glands?

Answer 16

Secretes alkali mucous

Question 17

What is the structure of the small intestinal epithelium?

Answer 17

The epithelium is made up of villi (peaks) and crypts of Leiberkuhn (clefts)

Question 18

What type of epithelia is found in the small intestinal lumen?

Answer 18

Simple columnar epithelium (with goblet cells)

Question 19

What types of cells are found in the crypts of Keiberkuhn?

Answer 19

• Enterocytes
• Stem cells
• Enteroendocrine cells
• Paneth cells

Question 20

What are the contents of the villous cores if the small intestines?

Answer 20

• Connective tissue
• Blood vessels
• Lymphatic vessels
• Immune cells
• Smooth muscle (from muscularis mucosae)

Question 21

What are the functions of the myenteric plexus?

Answer 21

Controls intestinal motility

Question 22

What are the functions of the submucosal plexus?

Answer 22

• Controls absorption
• Controls secretion
• Controls activity of muscularis mucosae