Histology High-Yield

Question 1

What are the distinguishing histologic features of the colon?

Answer 1

Will see simple columnar epithelium along with an abundance of goblet cells. Will see crypts of Lieberkuhn.
Also, villi are not present within the colon.
Semilunar folds may be present - these are essentially the same thing as plicae circulars or rugae and are made up of submucosa and mucosa

Question 2

What are the distinguishing histologic features of the appendix?

Answer 2

The appendix will looks similar to the colon with a layer of simple columnar epithelium, but it is characterized by a heavy amount of lymphoid tissue that essentially take over the structure. The overproliferation of the lymphoid tissue will lead to only a few glands/crypts of Lieberkuhn being present because everything else has been taken over basically.

Question 3

What is the muscular is mucosa?

Answer 3

Thick eosinophilic layer of smooth muscle located between the lamina propria and the submucosa in the alimentary tract. Ducts can pierce this layer

Question 4

What is the lamina propria?

Answer 4

A layer of connective tissue.

In the intestine, it makes up the inside of the villi. It is located between the epithelium and the muscularis mucosae.

Question 5

What are the distinguishing features of the duodenum?

Answer 5

Simple columnar epithelium with goblet cells interspersed. Will see the presence of villi.
The big distinguisher is the presence of Brunner’s glands within the submucosa - this will be below the eosinophilic band of muscularis mucosae

Question 6

How do you distinguish the Meissner’s plexus?

Answer 6

Meissner’s plexus is another name for the submuosal plexus. It will be between a layer of smooth muscle and the submucosa. To see if you are in the submucosa, should see the presence of fibroblasts. May also see glands nearby which will help distinguish this since the submucosal plexus is thought to help with glandular secretion.

Question 7

What are the distinguishing features of neurons to see if you are in a nerve plexus?

Answer 7

Nuclei will stain basophilic with a prominent nucleolus seen

Question 8

What is the difference between the features in a plicae circularis vs. a villus?

Answer 8

A plicae circularis will contain layers of submucosa and muscularis mucosa present in the center. These will also be seen in greatest concentration in the jejunum.
In contrast, villi contain a core of lamina propria and will see the submucosa and muscularis mucosa as distinct from them.

Question 9

What are the distinguishing histologic features of the gallbladder?

Answer 9

Will have a simple columnar epithelium without the presence of goblet cells. Also, just have a layer of muscularis externa without the presence of muscularis mucosae
Villus-like structures will also be seen within the gallbladder but these will be arranged and interconnected.

Question 10

What are the histologic features of a bile duct?

Answer 10

If part of a portal triad, will be located within connective tissue close to an artery and vein. In contrast to the artery and vein, the duct will be lined by simple columnar epithelium rather than endothelium (arteries and veins lined by endothelium).

Question 11

Where is there the highest concentration of goblet cells within the small intestine?

Answer 11

The ileum. The number of goblet cells present in the epithelium increases as you go down the alimentary tract.

Question 12

What are the distinguishing features of an enteroendocrine cell?

Answer 12

Will see clear cytoplasm with the nucleus present in the center of the cell
To distinguish whether its located within the small intestine or the stomach, look in the rest of the section to see if there are goblet cells present.

Question 13

What are the distinguishing features of chief cells?

Answer 13

Chief cells stain with a very basophilic cytoplasm due to the large presence of rough endoplasmic reticulum making pepsinogen

Question 14

What are the distinguishing features of Paneth cells?

Answer 14

Paneth cells are located in the intestine at the base of crypts of Lieberkuhn. Will see goblet cells in the section so that you are able to orient yourself to the location of pancreas. Cells will look like “raspberries” due to the presence of large refractive eosinophilic granules
These resemble mast cells, however, mast cells will be present in the lamina propria and also have basophilic granules - this is how you distinguish them

Question 15

What are the distinguishing features of the fundic stomach?

Answer 15

Will see simple columnar epithelium without the presence of goblet cells - more homogeneous.
No villi will be seen, but rather will have gastric pits. Parietal cells will be located in the center of the gland - these are present in highest concentration in the fundic stomach. Also pits are more shallow in narrow in comparison with the cardiac stomach.
Also, will see chief cells located at the base of the gland - these are present only in the fundic portion of the cytoplasm.

Question 16

What are the distinguishing features of parietal cells?

Answer 16

Parietal cells secrete HCl and will have a much more eosinophilic cytoplasm due to the abundance of mitochondria that provide ATP for the proton pump.
They may appear as binucleate cells.
They may resemble “fried eggs.”

Question 17

What are the distinguishing histologic features of the esophagus?

Answer 17

Very thick stratified squamous non-keratinizing epithelium with the basal layer appearing more basophilic that the surface layer.
Will see a thick and prominent muscularis mucosa composed of smooth muscle.

Question 18

What are the distinguishing features of the submandibular gland?

Answer 18

The submandibular gland is a mixed mucous and serous secreting gland so will see mucus-secreting cells interspersed with serous cells. Mucus cells will be characterized by a more lightly basophilic clear staining cytoplasm that looks more heterogeneous than adipocytes.

Question 19

How is the muscularis externa in the esophagus different than other elements of the alimentary tract?

Answer 19

It contains both smooth and striated muscle so will see smooth muscle next to skeletal muscle in section. In contrast, the colon, stomach, and small intestine have two layers of smooth muscle in the muscularis externa.

Question 20

What are the distinguishing histologic features of the pyloric stomach?

Answer 20

Will not see goblet cells and will see a homogeneous simple columnar epithelium. Gastric pits will be very long as well.

Question 21

What are the distinguishing features of the sublingual gland?

Answer 21

The sublingual gland is completely serous-secreting and will see acinus surrounded by eosinophilic connective tissue and a layer of myoepithelial cells surrounding the duct.
Nearly all cells present in the gland are mucus-secreting so will be lighter staining.

Question 22

What are the distinguishing features of the parotid gland?

Answer 22

The parotid gland is mostly serous-secreting and will see the presence of adipocytes as well within the gland.
The adipocytes will not be arranged in acini so this is how you know you are looking at fat vs. mucus-secreting cells.