GI Histology 1

Objectives

• Describe the cells of the GI tract and their function

• Describe the histological features of each part of the GI tract.

• Differentiate between different parts of the GI tract

• Appreciate the histopathology of the GI tract

• Describe the histological basis of some clinical problems

• The student should identify the following:

1. The parts of the digestive system

2. Each part’s functions

General Structure of the Digestive Tract

• The student should identify the common structural characteristics of the gastrointestinal tract

• It is a hollow tube composed of a lumen surrounded by a wall made up of four principal layers:

1. the mucosa2. Submucosa3. muscularis4. Serosa❖ (the student should know the

characteristics of each layer)

Basic mucosal forms in the GI tract

• The student should know the basic mucosal forms in the GI tract and examples on each one of them:

1. Protective

2.Seceretory

3. Absorptive

4. Absorptive/protective

The Oral Cavity

• The student should know the following:

➢ lining of all parts of the oral cavity 1. gingiva (gum)2. hard palate3. soft palate4. lips5. cheeks6. floor of the mouth.

Tongue

• The student should know the following:

1. the main tongue’s structures by which they vary according to the region

a. the lower (ventral) surface of the tongue

b. The tongue's dorsal surface

• The student should know the following:

The difference between the posterior one-third of the ventral surface of the tongue and the anterior two-thirds of the ventral surface of the tongue.

Papillae• The student should

know the following:

• 1. What are the types of the papillea and their functions

A. Filiform PapillaeB. Fungiform PapillaeC. Foliate PapillaeD. Circumvallate

Papillae

Taste buds

Salivary Glands

• The student should know the following:

1. what is saliva

2. Types of the large salivary glands, main characteristics and their functions

a. Parotid

b. submandibular (submaxillary)

c. sublingual glands

Parotid Gland

Submandibular (Submaxillary) Gland

Sublingual Gland

• The student should know the following:

1. The capsule that surrounds the large salivary glands.

2. The parenchyma of the glands

3. types of The secretory end pieces

4. duct system

• The student should differentiate between the following:

1. The Serous cellsand the mucous cells shapes, characteristics and functions.

2. Between the acini and tubules

Myoepithelial cells

• The student should know the following:

• 1. what are the Myoepithelial cells (basket cells)

• 2. their function

• The student should differentiate between the following:

• the intercalated ducts and the striated ducts

• Their lining

•

• The student should know the following:

• 1. the type of the glands’ stimulation

• 2. the sight of the vessels and nerves entrance in the large salivary glands

Minor Salivary Glands

• The student should know the following:

• 1. what are the minor salivary gland

• 2. What kind of secretions they produce