The Epidermis

By Casey and Sydney

What is the Epidermis?

- The epidermis is the outer most layer of the skin and it serves as protection from the outside world for the body.
- It's composed of stratified squamous epithelium.
- It also lacks blood vessels.

What are the Layers of the Epidermis?
(From top to bottom).

-Stratum Corneum: Made of a thick layer of dead cells. It also keeps the skin elastic and protects the skin from drying out. It also protects the tissue under it from things like infection or dehydration.
-Stratum Lucidum: Is a thin layer and in latin it means "clear layer" and it protects against Ultraviolet-ray damage.
-Stratum Grandulosum: Is the middle layer and starts keratinization (produces keratin). And this process starts the death of epithelial cells.
-Stratum Basale: Cells divide rapidly and make new cells, then the older cells get pushed up to the next layer.

What's so Special about the Epidermis?
(Specialized Cells)

-Melanocyte: Contains the pigment melanin. This cell makes the color in your skin and in your hair.
-Langerhans: Are the defense of the immune system for the skin.
-Keratinocytes: These cells are found in the bottom layer of the epidermis (these are the majority of the cells in the epidermis). These cells produce Keratin.


What Determines Skin Color?

-Skin color is determined by how much melanin you have.
-Skin color can also be affected by the amount of sunlight you get (ultra violet rays from sun lamps too).
-And finally long term exposure can cause sunburn and then if it’s gets worse then it could possibly turn into skin cancer.

What are Calluses and how are they formed?

-Calluses are tough patches of skin.
-Like extra protection for parts of your skin that get a lot of wear and tear.
-Caused by a lot of friction or pressure (heel rubbing in a shoe).
-When your skin is being put through a lot of pressure the dead skin cells on your hand (the last layer) build up more than they flake away. If the last layer of skin is about 25 dead cells thick then when more friction is applied more dead skin cells build up and cause a callus.
-If unchecked this callus can turn into a cone shaped sore called a corn and these can be really painful.

Interesting Facts about the Epidermis:

-The lowest layer of the epidermis (stratum basale) is close to the dermis so it is supplied with blood cells.
-On most areas of your body there are only four layers of skin but on the palms of your hands and the soles of your feet there are five layers.
-The thinnest part of your skin is about 0.05mm on the eyelids and about 1.5mm on the palms of your hands and on the soles of your feet.
-The top layer is made of dead cells that shed about every two weeks.

Diseases in or on the epidermis:

-Seborrhoeic Dermatitis: Called Seborrhoeic Eczema, triggered by stress and fatigue.
This is a condition that you had excess sebum and it only affects 1-3% of the adult population.
Basically a red appearance to the skin, small dry patches and they tend to itch.



Epidermis skin disorders or diseases often have to do with lack of melanin or disposal of basale cells.
Freckles also known as Vitiligo is also a skin disorder and moles can be a sign of cancer.


Integumentary System Song:

Works Cited

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"AdkPathCourse: Diseases of the Epidermis." AdkPathCourse. N.p., n.d. Web. 22 Oct. 2012. <>.
"Dermatology." Atlantic Health. N.p., n.d. Web. 22 Oct. 2012. <>.
"Skin - Anatomy - Skin Layers." Dermatology - Guide to Skin Conditions and Skin Care. N.p., n.d. Web. 22 Oct. 2012. <>.
"What Are Calluses And How Are They Formed? | A Moment of Science - Indiana Public Media." Indiana Public Media | News and Information, Music, Arts and Community Events from WFIU and WTIU. N.p., n.d. Web. 22 Oct. 2012. <>.
"YouTube - Integumentary System Song." YouTube - Broadcast Yourself.. N.p., n.d. Web. 22 Oct. 2012. <>.

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