Back To CourseMedical Terminology: Help & Review
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Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.
Today, we are going to discuss your amazing, incredible, and fascinating skin. What? You don't think your skin is amazing or incredible, nonetheless fascinating? Well, that's where you're wrong.
Think about this: This natural coat that we all wear is waterproof, expandable and easily cleaned, and it repairs itself when it's cut or burned. In this lesson, we will talk about the layers of your skin, namely the epidermis, dermis and subcutaneous tissue, and learn how structures within these layers make your skin so amazing. By the end of the lesson, I think you'll have a new appreciation for your skin.
The epidermis is the outermost layer of your skin, so when you look in the mirror, you're looking at your epidermis. This term is easy to remember if you recall that the prefix 'epi-' means 'above.'
Your epidermis is avascular, which means it doesn't have a blood supply. Not having a blood supply may sound like a bad thing, but there is at least one good thing that comes from this. This avascular trait explains why you can shave without bleeding.
The epidermis is a tough, protective layer. This quality is thanks to cells within the epidermis that produce a fibrous protein called keratin. As new epidermal cells are created deep inside the epidermis, they push older cells up toward the surface of your skin. These older cells flatten out, and grow increasingly full of keratin. Keratin is what makes your skin water resistant and tough. This strong outer coat protects the deeper layers of your skin from harmful environmental factors, like germs and chemicals, and helps lock in the things you need, like water.
Your epidermis also contains special cells called melanocytes. These cells make melanin, which is the pigment that contributes to your skin color. Melanocytes also respond to sunlight. When you sit out on the beach on a sunny summer day, your melanocytes produce more melanin, and your skin color gets darker.
The dermis is the layer of skin below the epidermis. Do you own a leather belt or handbag? Well, leather is actually the dermis, or 'hide,' of the animal that has been treated and prepared.
The dermis is attached to the epidermis, but instead of a nice straight dividing line, the division between the two layers appears to be bumpy. This bumpy appearance is due to the fact that the dermis pushes up into the epidermis at different areas. These indented areas contain capillaries, or tiny blood vessels that provide some nutrients to the epidermis as well as specialized receptors. Some of these receptors are free nerve endings that allow you to feel pain. Others, like the Meissner's corpuscles, allow you to perceive touch.
When I was little, I heard a story about the Snow Miser whose touch turned everything to snow. This story about the Miser's touch helps me remember that the Meissner's corpuscles help me to perceive touch.
As we look at the deeper areas of the dermis, we find larger blood vessels and sweat glands that both help with the regulation of your body temperature. We also find sebaceous glands, which are oil glands found in all parts of your skin except the palms of your hands and the soles of your feet. Oil from these glands help keep your skin soft.
Additional structures in the dermal layer are the Pacinian corpuscles, which are specialized receptors that allow you to feel pressure and vibration. If you think of the P's in Pacinian and pressure, it will help you recall this structure's job.
One of the most prominent structures in the dermis is the hair follicle, which is the pit that encloses the root of your body hairs. Did you ever get the chills and notice that you had goose bumps that raised the hairs on your arms? That hair standing erect was caused by a contraction of the arrector pili muscles, which are tiny muscles that attach to each hair root. When you're cold and scared, these muscles contract, giving you goose bumps.
The dermis also contains phagocytes. If we break this term down we see that 'phago' refers to 'eating,' and 'cytes' refers to 'cells.' Therefore, phagocytes are eating cells that like to gobble up harmful invaders, like bacteria. These phagocytes provide you with an added layer of protection, keeping your insides safe against any foreign invaders that happen to penetrate the epidermis.
Throughout the dermis, you'll find collagen fibers and elastic fibers. Collagen adds to the toughness of your skin, but it also helps your skin hold on to water. The elastic fibers are the wonderful fibers that give youthful skin its springy quality. As you age, these elastic fibers, along with the collagen fibers and supporting fatty tissue, begin to breakdown and you start to notice wrinkles.
The lowest layer is more of a supporting structure than an actual part of the skin. I'm talking about the subcutaneous tissue found under the dermis. The position of this layer is easy to recall if you remember that the prefix 'sub-' means below, and the suffix '-cutaneous' refers to skin.
This layer helps to anchor the dermis to your muscles, bones, and organs. It contains a lot of fat. The fat acts as a shock absorber and helps insulate the body, which controls your body temperature. Of course, this fatty layer just below the skin is also what gives your body the curves and shape that's unique to you.
Let's review. The epidermis is the outermost layer of your skin. The fibrous protein called keratin that's found in this layer helps to make it tough, protective and waterproof. The epidermis also contains melanocytes, which make the skin pigment melanin.
The dermis is the layer of skin below the epidermis. It contains specialized receptors, including the Meissner's corpuscles, which allow you to perceive touch, and the Pacinian corpuscles, which are specialized receptors that allow you to feel pressure and vibration. The dermis also contains, blood vessels, sweat glands and sebaceous glands, which are oil glands.
One of the most prominent structures of the dermis is the hair follicle, which contains the root of your body hairs. These hairs can stand erect and give you goose bumps, when the arrector pili muscles contract. The dermis also contains phagocytes that like to eat bacteria, as well as collagen fibers and elastic fibers, which give young skin its smooth springy look.
Under the dermis is the subcutaneous tissue. This fatty layer helps to anchor the dermis to your muscles, bones and organs, acts as a shock absorber, and helps insulate the body.
By the time you reach the end of the lesson, it should be possible to:
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Back To CourseMedical Terminology: Help & Review
30 chapters | 408 lessons