3.3 The Histology of the Gut Tube Flashcards
What are the Layers of the Gut Tube found constantly throughout the Alimentary Tract?
- The Mucosa
a) The Epithelium
b) The Lamina Propria
c) Muscularis Mucosae (Interna) - The Sub-Mucosa
- The Muscularis Externa
a) Circular Muscle
b) Longitudinal Muscle - The Serosa / Adventitia
What types of Muscle form the Muscularis Externa in the Oesophagus?
Proximal 1/3 - Skeletal Muscle
Middle 1/3 - Mix of Smooth Muscle and Skeletal Muscle
Distal 1/3 - Smooth Muscle
What kind of Surface Epithelium is present on the Oesophagus?
Stratified Squamous Epithelium
for the protective function
What type of Muscle is the Muscularis Mucosae (Interna)?
Smooth Muscle
Where are the larger Blood Vessels found in the Oesophagus?
In the Sub-Mucosa
What are the large folds present in the wall of the Stomach known as?
Gastric Folds (Rugae)
What are the Gastric Pits?
They are indentations in the Stomach which denote entrances to the Tubular Gastric Glands
What do secretory cells are present in the Gastric Glands?
Surface Mucous Cells
What are the folds which extend into the Lumen of the Small Intestines called?
Circular, Mucosal Folds
What is superimposed on these Large Circular Mucosal Folds?
Villi - Finger like processes
What is the function of these Villi?
To increase the Surface area to aid absorption
What Surface Epithelium is present on the Villi?
Simple Columnar
What is present in the Lamina Propria?
Glands
Do the Glands extend further down than the Muscularis Mucosae (Interna)?
No
What are the names of these Glands which are adjacent to the Villi, and do not extend beyond the Muscularis Mucosae?
The Crypts of Lieberkuhn
What are the Crypts of Lieberkuhn responsible for?
The secretion of Intestinal “Juice”, and the replenishment of cells begins here
Where along the Gut Tube do glands extend down beyond the Muscular Mucosae (Interna), into the Sub-Mucosa?
- In the Oesophagus
2. In the Duodenum - Just above the Major Duodenal Papilla (Sphincter of Oddi)
What is secreted from the Oesophageal Glands (Goblet Cells) in the Sub-Mucosa?
Mucin - For lubrication of the Bolus
What is secreted from the Duodenal Glands (Goblet Cells) in the Sub-Mucosa?
Mucin rich Bicarbonate solution, to:
- Neutralize the Acid Content of the Chyme
- Allow the Intestinal Enzymes to be Active
- Lubricate the Intestinal Walls
What type of cells are present in the Surface Epithelium of Small Intestines?
Tall, Columnar, Enterocytes (Absorptive Cells)
Where can Payers Patches (Lymph Nodules) be viewed?
Within the Mucosa of (mostly) the Ileum
What are the 3 predominant cells present in the Surface Epithelium of the Colon?
- Columnar Absorptive Cells
- Goblet Cells
- Endocrine and Basal Stem Cells
What do the Columnar Absorptive Cells absorb?
Water and Electrolytes
What do the Goblet Cells secrete?
Mucin - as lubrication
What kind of Surface Epithelium is present on the Recto-Anal Junction?
Stratified Squamous (for the protective function)