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Melanin

A pigment that gives color to skin and eyes and helps protect it from damage by ultraviolet light.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

Schematic representation of normal skin; drawing shows normal skin anatomy, including the epidermis, dermis, hair follicles, sweat glands, hair shafts, veins, arteries, fatty tissue, nerves, lymph vessels, oil glands, and subcutaneous tissue. The pullout shows a close-up of the squamous cell and basal cell layers of the epidermis, the basement membrane in between the epidermis and dermis, and the dermis with blood vessels. Melanin is shown in the cells. A melanocyte is shown in the layer of basal cells at the deepest part of the epidermis. Click to enlarge

Parts of the skin with close-up of cells National Institutes of Health

Terms to know

Arteries
A blood vessel that carries blood from the heart to tissues and organs in the body.
Basal Cells
A small, round cell found in the lower part (or base) of the epidermis, the outer layer of the skin.
Blood Vessels
Tubes that carry blood to and from all parts of the body. The three main types of blood vessels are arteries, capillaries, and veins.
Body Fat
Excess calories are stored as body fat, providing the body with a reserve supply of energy and other functions.
Body Membrane
A very thin layer of tissue that covers a surface.
Dermis
The inner layer of the two main layers of the skin. The dermis has connective tissue, blood vessels, oil and sweat glands, nerves, hair follicles, and other structures. It is made up of a thin upper layer called the papillary dermis, and a thick lower layer called the reticular dermis.
Epidermis
The outer layer of the two main layers of the skin.
Hair Follicle
The hair follicle is a tube-shaped sheath that surrounds the part of the hair that is under the skin and nourishes the hair.
Hair Shaft
The segment of the hair that projects above the skin surface.
Lymphatic Vessels
A thin tube that carries lymph (lymphatic fluid) and white blood cells through the lymphatic system. Also called lymph vessel.
Melanocytes
A cell in the skin and eyes that produces and contains the pigment called melanin.
Nerves
A bundle of fibers that receives and sends messages between the body and the brain. The messages are sent by chemical and electrical changes in the cells that make up the nerves.
Sebaceous Glands (Oil Glands)
Small glands located within the epidermis, and associated with the hair follicle, that produce and secrete an oily substance that lubricates the skin and hair.
Skin
The outer covering of the body that protects it from the environment.
Squamous Cells
Flat cell that looks like a fish scale under a microscope. These cells cover inside and outside surfaces of the body. They are found in the tissues that form the surface of the skin, the lining of the hollow organs of the body (such as the bladder, kidney, and uterus), and the passages of the respiratory and digestive tracts.
Subcutaneous
Beneath the skin.
Sweat Glands
The small coiled tubes in the skin that produce and secrete sweat.
Tissue
A group of cells that act together to carry out a specific function in the body. Examples include muscle tissue, nervous system tissue (including the brain, spinal cord, and nerves), and connective tissue (including ligaments, tendons, bones, and fat). Organs are made up of tissues.
Ultraviolet Radiation (UV Radiation)
Invisible rays that are part of the energy that comes from the sun. UV radiation that reaches the Earth's surface is made up of two types of rays, called UVA and UVB.
Veins
Blood vessels that carry blood to the heart.

Terms to know

Arteries
A blood vessel that carries blood from the heart to tissues and organs in the body....
Basal Cells
A small, round cell found in the lower part (or base) of the epidermis, the outer layer of the skin....
Blood Vessels
Tubes that carry blood to and from all parts of the body. The three main types of blood vessels are arteries...
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