histo how-to

If you are planning on going into a medical professional field and your school offers histology for undergrads, I highly encourage you to take it. The content is dense, but I believe it is a great preparatory course for several professional programs. I am happy to share with you a few tips that helped me with the course!

First off, let me explain. Histology, broken down, is the study of tissue. (hist/o = tissue, -ology = the study of). As many of us know, our tissues make up our organs. Studying histology allows us to understand the anatomy + physiology of our bodies better from a microscopic perspective. Learning how different cell types, fibers, and structural units that make up each structural element of the body is remarkable and a privilege!

Here is how I can help!

  1. Learn the terminology.

I can’t reiterate the importance of knowing WHAT you’re talking about enough. Knowing the difference between what endothelium & epithelium are may help you with a test question. Endothelium (endo- = inside) lines the inside of the blood vessels and has very diverse properties. Epithelium (epi- = above), is the usually the outermost layer of surfaces such as skin, glands, and lines ducts. What do reticular fibers do? Reticular means “to form a net” and that’s exactly what these fibers do. Reticular fibers form a meshwork for migration of immune cells throughout organs. What about looking at cancers? An ADENOcarcinoma is a glandular cancer. (aden/o = gland, carc/o = epithelial origin, -oma = tumor). When seeing abnormal tissue that is attempting for form glands, you’ll know instantly it is an adenocarcinoma.

2.  Know your stains.

The most basic stain (ok, maybe I shouldn’t use the term basic in this case), is H & E – hemotoxylin/eosin staining. That’s the stain that makes everything look purple/bluish. Knowing what stains darker and what stains lighter, or what stains with special stains will help you to determine what you’re looking at.

PAS – stains PINK/MAGENTA; stains carbohydrate (specifically glycogen).

Nissl staining – stains RER (nissl bodies in the nervous system).

Reticulin – stains highlights reticular fibers in the bone marrow.

If you know what you’re looking for, and what stain is attracted to chemically, it will make the process much more understandable.

nissl stain
nissl staining in the nervous tissue! 

3. Learn the cell types.

The digestive tract is full of different kinds of cells that are fundamental in the role of the organ. The stomach has chief cells, parietal cells, enteroendocrine cells among others. What do each of these things do? Where are they located? What do they secrete? What do they look like?

For example, parietal cells are “fried egg cells” with a small, centered nucleus, abundant cytoplasm, bubbly appearance, and are found in the gastric glands of the stomach. They secrete HCl, or stomach acid.

gastric chief and parietal cells
PC = parietal cells, CC = chief cells. Do the parietal cells remind you of a fried egg? 😀

4. Look for landmarks.

How do you know you’re looking at the gallbladder? What is distinct about the appendix? Where are the smallest, primordial follicles in the ovary? Finding distinct features about each organ will help you to determine what you’re looking at if you aren’t sure from 40x or more.

The gallbladder is highly folded with no submucosa.

gallbladder.jpg
gallbladder

 

The appendix is a muscular tube rich in GALT, or gut-associated lymphatic tissue. What is the cause of appendicitis? Why are appendectomies the medical solution? Think about it in relation to this slide!

appendix histo .jpg
appendix 4x. Pink = muscular layers, purple = GALT. 

 

The primordial, or most immature follicles are found around the ovarian cortex. They are smallest in size. As the follicles mature and get bigger, they also move inwards closer to the middle of the medulla of the ovary.

ovary
primordial follicles along the outer edge of the ovary, Graffian (or mature) follicle in the medulla. Notable size difference? *the oocytes, or egg cells, are found in the middle of the follicles; the small purple dots. 

 

5. Use available online resources.

Below are links to the websites I have used to help prepare me for lab practicals. There are plenty out there, but these were the most helpful to me.

Histology Guide – a virtual slide box with zoom capabilities, labeled diagrams, and thorough explanations. Helpful to view slides from lab at home on the computer.

Histology World – quiz resources, lecture outlines, and more slide images. Practical quizzes that help prepare for lab exams.

Blue Histology – description and visuals of more slides

IMG_1735
knowledge is power 😀

I wish you all the best of luck in your studies, and I hope you learn to love histology as much as I did. It’s truly beautiful. As you learn it, this branch of biology, you will probably find yourself admiring the stain colors, and the seemingly-minute details of the human body.

PS: if you’re interested, read about my experience shadowing in PATH after I finished the semester of histology – something I recommend 😀

*Photo sources:

Nissl staining: New York University Medicine

Parietal cells: Austin Peay State University

Gallbladder: John’s Hopkins School of Medicine

Appendix: Concordia College, Moorhead

Ovary: University of South Wales

Header image is my own: taken at the University of North Dakota. Shows the corneal endothelium/iris junction. 

 

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