Histology - Esophagus; Stomach

Front 1

Esophagus

Back 1

Tube that connects oral cavity to the stomach. Upper 1/3 is skeletal muscle for swallowing purposes. Lower third all the way down to the anus is smooth muscle. It is made of stratified squamous epithelium because the esophagus can easily be scratched via sharp food, so this epithelium is advantageous.

Front 2

Three layers of Mucosa (from top to bottom)

Back 2

Epithelium, Lamina propria (Connective Tissue), Muscularis Mucosae (Muscles of Mucus - is always smooth muscle - local contractions, not as large as peristalsis)

Front 3

Layers of Muscularis Mucosae (from top to bottom)

Back 3

1) Submucosa - connective tissue

2) Muscular Propia or Externa - made up of circular layer (has bigger, more spread cells) and longitudinal layer (outer layer - smaller closer packed cells)

Front 4

Meissner's or Submucosal Plexus

Back 4

Type of parasympathetic ganglion, found in the submucosa, contains ganglia from which nerve fibers pass to the muscularis mucosae and to the mucous membrane

Front 5

Auerbach's or Myenteric Plexus

Back 5

cells found in circular and longitudinal sublayers (Muscular propia, which is under submucosa), provides motor innervation to both layers and secretomotor innervation to the mucosa.

Front 6

Three Functions of Stomach

Back 6

1) Food storage
2) HCl - breakdown of CT, muscle, kills bacteria
3) Enzymes - protein digestion

Front 7

What happens to the rugae of the stomach is not relaxed?

Back 7

If the stomach is full, the rugae would be all stretched out with no folds - "underwear" analogy.

Front 8

Layers of stomach in cross section (from top to bottom)

Back 8

Lumen, muscular mucosae, submucosa, muscularis propia (made up of circular then long), then serosa

Front 9

Gastric Pits

Back 9

Lined with mucous cells, whose nuclei are near the basement membrane (the outside). Is short compared to the gastric gland. Located at the top/isthmus.

Front 10

Gastric Gland

Back 10

Long gastric gland compared to short gastric pit. found in the fundus of the stomach, lined throughout by columnar epithelium. Located in the middle.

Front 11

Parietal Cell

Back 11

Located in the gastric gland, secrete HCl and Gastric Intrinsic Factor (GIF), which is a protein-carbohydrate = glycoprotein. They also aid in the absorption of vitamin B12 across enterocytes in the small intestine. Their nuclei are surrounded by pink cytoplasm. They can be found in the chief cell region but not vice versa.

Front 12

Chief Cells

Back 12

Located in the base of the stomach. They secrete pepsinogen, which travels north and comes in contact with HCl made by the parietal cells, producing the active enzyme called pepsin, which begins protein digestion. The cytoplasm in which the chief cells are located stains more heavily than the top portions of the stomach.

Front 13

Meisnner's Plexus/Other Cells

Back 13

Meisnner's Plexus can stimulate the muscularis mucosae via gastrin secretion. Other cells in the stomach include the endocrine cell, whose main hormone secretion is gastrin (not seen in lab)

Front 14

Pyloric (location)

Back 14

Located underneath the fundic and corpus of the stomach, and above the pyloric sphincter and beginning of small intestine (duodenum.

Front 15

Mucosa Layer of Pyloric

Back 15

Top portion of this layer is made up of gastric pits (very long and straight). The bottom layer is made up of pyloric glands and the muscular mucosae

Front 16

Pyloric Glands

Back 16

Are coiled and secrete mucus