Labeled diagram of the skin & skin stem cells in research

I’ve been teaching Histology here at UC Davis School of Medicine for more than 12 years and I lecture on skin among other topics so I’ve made more than one labeled diagram of the skin over the years. I’ve included some in this post.

First, below you can see a zoomed0out view of fingertip with just the major layers labeled.

Further down I have a second, more zoomed diagram with clear views of epidermal layers.

While my lab doesn’t study skin stem cells, I am very interested in them. Research in that area has come a long way over the past couple decades.

Labeled diagram of the skin
Labeled diagram of the skin. Big picture view. Source, Professor Paul Knoepfler, UC Davis School of Medicine.

Teaching skin histology

Our team-taught course has some fantastic microscopy images from just about every tissue including skin.

My lecture on integument, as skin is more formally called along with its associated structures like hairs and glands, often sparks many questions from the first year students. In part I think that’s because skin is such a part of everyday life. Most of us don’t necessarily think about our various organs and tissues on a daily basis, but in contrast skin and hair might be on our minds that often.

A very high percentage of people have to deal with various skin conditions too.

Lecturing on the histology of skin and doing the laboratory sessions with the students is especially rewarding because in many cases we can explain at a cellular level what is going on with specific skin conditions. Like I said I also find epidermal stem cells to be fascinating.

labeled diagram of epidermis
Labeled diagram of the skin epidermis. Source, Professor Paul Knoepfler, UC Davis School of Medicine.

Labeled diagram of the skin: epidermis, skin stem cells

I’ve included another labeled diagram of skin here with specific annotations for important epidermal layers.

This is more zoomed in than the first figure at the top of the post.

The home of one population of skin stem cells, also called epidermal stem cells, is in the stratum basale at the bottom of the epidermis.

There is another population of skin stem cells associated with the hair follicle in the dermis as well. These epidermal stem cells associated with the hair seem particularly important for recovery from burn injury.

The University of Leeds has a great on-line skin histology resource. Check it out.

Regenerative therapies for skin

In some ways, skin might be one of the more approachable tissues to treat with cell therapies. Skin is external and consists of sheet-like structures that can be engineered in the lab.

There have also been some exciting clinical developments with cell therapy for skin injury. There is real promise here and some of this work is further along than many other regenerative approaches in the pipeline.

Unfortunately, the cosmetics-based idea of skin stem cell care has taken off even though there are few data to support it. It’s important to be cautious in this space.

Some clinics also claim that they can treat specific skin problems with stem cells, but here again we don’t see good data for that yet.

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