Stomach, Small Intestine, Appendix, Large Intestine

A: Gastric epithelium is simple columnar epithelium

B: Gastric glands have differential staining due to the different cells that make up the gastric gland. The parietal and the chief cells cause the gland to stain pink and purple respectively. The glands also cause the stomach to have a characteristic crenelated castle wall shape.

C: The submucosa of the stomach is full of vasculature and loose connective tissue

A: Simple columnar epithelium lines the interior of the stomach

B: The gastric pits are invaginations in the wall of the stomach. These give the stomach mucosa a crenelated wall effect.

C: Parietal cells stain pink due to their acidic product hydrochloric acid

D: Chief cells stain purple due to their basic product pepsinogen

A: Simple Columnar epithelium

B: Gastric pits line the inside of the stomach increasing the surface area

A: Simple columnar with a striated border lines the inside of the small intestine. The microvilli that make up the striated border serve to increase the surface area of the small intestine so nutrient absorption can take place. The striated border can be indentified by a light pink fringe or haze on the edges of the cells instead of an abrupt end of the cells cytoplasm.

B: Evaginations (villi) of the mucosa. The base of these evaginations start at the same level at the base but vary in length. This also increases the surface area of the small intestine.

C: Intestinal crypts or Crypts of Lieberkühn where paneth cells secrete their products

D: Brunner's glands are located in the submucosa and secrete basic pH enzymes. This is one of the easiest ways to differentiate the small intestine from the large intestine which has no glands

E: The submucosa is where there is lots of vasculature, glands and nerve plexi

A: Intestinal Crypts house the paneth cells which secrete enzymes

B: Goblet cells which are also found in the respiratory system secrete mucous and aide in movement of the bolus through the GI tract and also protect the intestinal epithelium

A: Goblet cells are interspersed throughout the epithelium of the small intestine. They are more prevalent in the large intestine than in the small intestine.

B: Simple columnar epitheliumwith a striated border. The microvilli can be seen as a light fringe just outside the cell membrane. The cell membrane will usually stain darker than the striated border so if zoomed in close enough the border can be easily distinguished.

C: Central lacteal is a lymphatic vessel that drains lymph and some fats from the small intestine. It is found running down the middle of the large villi or evagniations of the small intestine. They are lined with simple squamous epithelium

A: Dense lymphatic tissue is prevalent in the appendix. It is found in the submucosa.

B: The invaginations of the mucosa are lined by a layer of simple columnar epithelium with a striated border. The appendix is a mix of the large intestine and small intestine. It has invaginations like the large intestine and it has a striated border like the small intestine.

C: Trash in the lumen is very commonly seen in the lumen of the appendix

A: Goblet cells are also found in the appendix

B: Trash located in the lumen

C: Simple columnar epithelium with a striated border. You can see the hazy border along the edge of the epithelial cells

A: Simple columnar epithelium with a striated border

B: Goblet cell

A: Invaginations of the mucosa are lined by simple columnar epithelium and goblet cells

B: Mucosa houses epithelium and has loose connective tissue on the interior

C: Submucosa house nervous tissue and vasculature

D: Muscularis externa is broken into two seperate layer. The inner circular and the outer longitudinal

A: Mucosa

B: Goblet cells secrete glycosamineglycan or mucous that lines the lumen of the large intestine. The ratio of goblet cells to epithelial cells is much higher in the large intestine than in the small intestine

C: Submucosa

D: Muscularis externa

A: Goblet cells. The ratio here is much higher than the small intestine

B: Simple columnar epithelium without the striated border. There is no visible border on the edge of these cells