The document summarizes the anatomy and histology of the esophagus. It describes the four main layers of the esophagus - mucosa, submucosa, muscularis, and serosa/adventitia. The mucosa contains epithelium, lamina propria, and muscularis mucosae. The submucosa contains esophageal glands and the plexus of Meissner. The muscularis contains two layers of smooth muscle - inner circular and outer longitudinal, as well as the plexus of Auerbach. The outermost layer is the serosa or adventitia. The document then provides more details on the histology and cell types of each layer.

2. •Oesophagus
•Stomach
•Small Intestine
•Large Intestine

3. Basic Histological Layers:
1. Mucosa:
a. Epithelium
b. Lamina Propria
c. Muscularis Mucosae
2. Submucosa:
Submucosal plexus
“Plexus of Meissner”
3. Muscularis:
Myenteric plexus
“Plexus of Auerbach
4. Serosa/Adventitial layer

4. Mucosa
• The mucosa is surrounded by a dense, irregular
fibroelastic connective tissue layer, the submucosa
Submucosa
• The muscularis externa is usually composed of
inner circular and outer longitudinal smooth
muscle layers.
Serosa and
Adventitia
• The muscularis externa is enveloped by a thin
connective tissue layer that may or may not be
surrounded by the simple squamous epithelium of
the visceral peritoneum.

5. The enteric nervous system, innervating
the alimentary canal, is modulated by
sympathetic and parasympathetic
nervous systems
Sympathetic (blue) and parasympathetic
(pink) innervation of the gastrointestinal
tract through vagal, sympathetic pelvic
pathways

6. The esophagus is a muscular tube, approximately 25 cm in
length, that conveys the bolus (masticated food) from the oral
pharynx to the stomach. Along its entire length, its mucosa
presents numerous longitudinal folds with
intervening grooves that cause the lumen to appear to be
obstructed; however, when the esophagus is distended the
folds disappear and the lumen becomes patent.
Anatomy structure
Extends from C6 to T11 or T12

7. • The lumen of the
esophagus, lined by a 0.5-
mmthick, stratified
squamous nonkeratinized
epithelium, is usually
collapsed and opens only
during the process of
swallowing
epithelium
• unremarkable. It houses
esophageal cardiac glands,
which are located in two
regions of the esophagus,
one cluster near the pharynx
and the other near its
juncture with the stomach.
lamina propria • is unusual in that it consists
only of a single layer of
longitudinally oriented
smooth muscle fibers that
become thicker in the
vicinity of the stomach
muscularis
mucosae

9. Light micrograph of the esophagus
(×17). Note that the lumen is lined by
a relatively thick stratified squamous
epithelium E) that forms a well-
developed rete apparatus with the
underlying lamina propria (LP). The
submucosa (S) is surrounded by a
thick muscularis externa, composed
of inner circular (IC) and outer
longitudinal (OL) muscle layers.

10. ⦿ The submucosa of the esophagus is composed of a
dense, fibroelastic connective tissue, which houses the
esophageal glands proper. The esophagus and the
duodenum are the only two regions of the alimentary
canal with glands in the submucosa. Electron micrographs
of these tubuloacinar glands indicate that their
secretory units are composed of two types of cells,
mucous cells and serous cells.
⦿ Mucous cells have basally located, flattened nuclei
and apical accumulations of mucus-filled secretory
granules. The second cell type is serous cells, with
round, centrally placed nuclei. The secretory granules
of these cells contain the proenzyme pepsinogen and
the antibacterial agent lysozyme. The ducts of these
glands deliver their secretions into the lumen of the
esophagus.

11. The different between the layers

12. The muscularis externa of the esophagus is arranged
in two layers, inner circular and outer longitudinal.
However, these muscle layers are unusual in that they
are composed of both skeletal and smooth muscle
fibers. The muscularis externa of the upper third of the
esophagus has mostly skeletal muscle; the middle thirdthird has
only smooth muscle fibers. Auerbach’s plexus
occupies its usual position between the inner circular
and outer longitudinal smooth muscle layers of the muscular is
Externa The esophagus is covered by an adventitia until it
pierces the diaphragm, after which it is covered by a serosa.