Everything You Need to Know About the Dermis

Woman touching face
The dermis is just under the top layer of skin.. Image Source/Getty Images

The dermis is the second layer of the three major layers of layers of skin, located between the epidermis and subcutaneous tissues, also known as the subcutis and the hypodermis. The dermis has connective tissue, blood capillaries, oil and sweat glands, nerve endings and hair follicles. There are two part of the dermis: a thin, upper layer known as the papillary dermis, and a thick, lower layer known as the reticular dermis.

Its thickness varies depending on the location of the skin. For example, the dermis on the eyelids is 0.6 millimeters; on the back, the palms of hands and the soles of feet it's 3 millimeters.

It's also composed of three types of tissues that are present throughout the dermis, not in layers:

  • Collagen
  • Elastic tissue
  • Reticular fibers

The papillary layer, the upper layer of the dermis, contains a thin arrangement of collagen fibers. The lower, reticular layer is thicker and made of thick collagen fibers that are arranged parallel to the surface of the skin.

What Does the Dermis Do?

The dermis is the thickest layer of skin and arguably the most important. It plays several key roles, including:

  • Producing sweat. Within the dermis are sweat glands that produce sweat that comes out of the pores. The body sweats as a way to cool itself off, regulate temperature and flush out toxins. There are more than 2.5 million sweat glands on the body, and there are two different types: apocrine and eccrine. Apocrine sweat glands are found in the more odorous parts of the body, including the armpits, scalp and genital region. The sweat glands, which become active during puberty, secrete their substances into the hair follicles. The sweat that is secreted is actually odorless at first; it only starts to smell when it comes in contact with skin bacteria. Eccrine sweat glands are located throughout the rest of the body: on the palms, the soles of feet, armpits and the forehead. These glands emit their substances directly to the surface of the skin.
  • Producing oil. The sebaceous glands produce sebum, or oil. Sebum prevents bacterial growth on the skin and conditions the hair and skin. If the follicle in which sebaceous glands are located becomes clogged with excess oil or dead skin cells, a pimple develops.
  • Growing hair. Hair follicles are located in the dermis. Every follicle root is attached to tiny muscles, known as arrector pili muscles, that contract when the body becomes cold or scared, causing goosebumps.
  • Feeling. The dermis is full of nerve endings that send signals to the brain about how things feel: if something hurts, itches, feels good, etc.
  • Distributing blood. Blood vessels are located in the dermis, which feed the skin and remove toxins.
  • Protecting the rest of the body. The dermis contains phagocytes, which are cells that consume potentially harmful toxins and impurities, including bacteria. The dermis already protects the body, but the phagocytes provide an additional layer of protection from anything harmful that has penetrated the epidermis.

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