3.3 The Histology of the Gut Tube

Question 1

What are the Layers of the Gut Tube found constantly throughout the Alimentary Tract?

Answer 1

1. The Mucosa
   a) The Epithelium
   b) The Lamina Propria
   c) Muscularis Mucosae (Interna)
2. The Sub-Mucosa
3. The Muscularis Externa
   a) Circular Muscle
   b) Longitudinal Muscle
4. The Serosa / Adventitia

Question 2

What types of Muscle form the Muscularis Externa in the Oesophagus?

Answer 2

Proximal 1/3 - Skeletal Muscle
Middle 1/3 - Mix of Smooth Muscle and Skeletal Muscle
Distal 1/3 - Smooth Muscle

Question 3

What kind of Surface Epithelium is present on the Oesophagus?

Answer 3

Stratified Squamous Epithelium
(for the protective function)

Question 4

What type of Muscle is the Muscularis Mucosae (Interna)?

Answer 4

Smooth Muscle

Question 5

Where are the larger Blood Vessels found in the Oesophagus?

Answer 5

In the Sub-Mucosa

Question 6

What are the large folds present in the wall of the Stomach known as?

Answer 6

Gastric Folds (Rugae)

Question 7

What are the Gastric Pits?

Answer 7

They are indentations in the Stomach which denote entrances to the Tubular Gastric Glands

Question 8

What do secretory cells are present in the Gastric Glands?

Answer 8

Surface Mucous Cells

Question 9

What are the folds which extend into the Lumen of the Small Intestines called?

Answer 9

Circular, Mucosal Folds

Question 10

What is superimposed on these Large Circular Mucosal Folds?

Answer 10

Villi - Finger like processes

Question 11

What is the function of these Villi?

Answer 11

To increase the Surface area to aid absorption

Question 12

What Surface Epithelium is present on the Villi?

Answer 12

Simple Columnar

Question 13

What is present in the Lamina Propria?

Answer 13

Glands

Question 14

Do the Glands extend further down than the Muscularis Mucosae (Interna)?

Answer 14

No

Question 15

What are the names of these Glands which are adjacent to the Villi, and do not extend beyond the Muscularis Mucosae?

Answer 15

The Crypts of Lieberkuhn

Question 16

What are the Crypts of Lieberkuhn responsible for?

Answer 16

The secretion of Intestinal “Juice”, and the replenishment of cells begins here

Question 17

Where along the Gut Tube do glands extend down beyond the Muscular Mucosae (Interna), into the Sub-Mucosa?

Answer 17

1. In the Oesophagus
2. In the Duodenum - Just above the Major Duodenal Papilla (Sphincter of Oddi)

Question 18

What is secreted from the Oesophageal Glands (Goblet Cells) in the Sub-Mucosa?

Answer 18

Mucin - For lubrication of the Bolus

Question 19

What is secreted from the Duodenal Glands (Goblet Cells) in the Sub-Mucosa?

Answer 19

Mucin rich Bicarbonate solution, to:
1. Neutralize the Acid Content of the Chyme
2. Allow the Intestinal Enzymes to be Active
3. Lubricate the Intestinal Walls

Question 20

What type of cells are present in the Surface Epithelium of Small Intestines?

Answer 20

Tall, Columnar, Enterocytes (Absorptive Cells)

Question 21

Where can Payers Patches (Lymph Nodules) be viewed?

Answer 21

Within the Mucosa of (mostly) the Ileum

Question 22

What are the 3 predominant cells present in the Surface Epithelium of the Colon?

Answer 22

1. Columnar Absorptive Cells
2. Goblet Cells
3. Endocrine and Basal Stem Cells

Question 23

What do the Columnar Absorptive Cells absorb?

Answer 23

Water and Electrolytes

Question 24

What do the Goblet Cells secrete?

Answer 24

Mucin - as lubrication

Question 25

What kind of Surface Epithelium is present on the Recto-Anal Junction?

Answer 25

Stratified Squamous
(for the protective function)