Dictionary > Melanocyte

Melanocyte

Definition

noun, plural: melanocytes

A type of pigment cell that, in particular, produce melanin, and occurs in the epidermal layer of the skin, in the uveal layer of the eye, the inner ear, the meninges, the heart, and the bones

Supplement

Pigment-producing cells (chromatophores) may be classified based on the colors (or hue under white light) of the pigment the cells produce: (1) xanthophores (yellow), (2) erythrophores (red), (3) iridophores (reflective/iridescent), (4) leucophores (white), (5) melanophores (black/brown), and (5) cyanophores (blue). According to Thody and Shuster, melanophores in the skin are further divided into two types based on their location: dermal melanophores and epidermal melanophores (melanocytes).1
A melanocyte (typically 7 μm in length) is a cell that produces melanin. Melanin is the natural pigment in the body and is responsible for the color of the skin, hair, and eyes. It is synthesized and stored within a special organelle, i.e. the melanosome. The melanocyte has cellular processes called dendrites. These dendritic processes allow the mobilization of melanosomes into neighboring keratinocytes of the skin.1 Melanogenesis is the process of producing melanin. It is a means of the body to protect the underlying skin layer such as the hypodermis from the adverse effects (e.g. DNA photodamage) of UV-B light exposure. The black (or dark brown) pigment allows the absorption of the majority of the UV-B light passing through the skin layer.2 Thus, increased exposure to UV-B radiation leads to heightened melanogenesis. Melanocytes are located in the stratum basale of the epidermal layer of the skin. In humans, there are usually about 1000 to 2000 melanocytes per mm2 of the skin. They can also be found in the uveal layer of the eye, the inner ear, the meninges, the heart, and the bones.

See also:

Reference(s):

1 Thody, A.J., Shuster, S. (1989) Melanophores, Melanocytes and Melanin: Endocrinology and Pharmacology. In: Greaves M.W., Shuster S. (eds) Pharmacology of the Skin I. Handbook of Experimental Pharmacology, vol 87 / 1. Springer, Berlin, Heidelberg.

2 Agar, N. & Young, A. R. (2005). “Melanogenesis: a photoprotective response to DNA damage?”. Mutation Research. 571 (1–2): 121–32.


You will also like...

Ecological Research Measuring & Analysis
Ecological Research: Measuring & Analysis

This lesson is about the methods used for ecological research, such as quadrat and transect sampling, canopy fogging, an..

A sperm cell fertilizing an ovum
Human Reproduction and Fertilization

For human species to obviate extinction, reproductive mature adults should be producing viable offspring in order to con..

Energy pyramid
Freshwater Community Energy Relationships – Producers & Consumers

This tutorial looks at the relationship between organisms. It also explores how energy is passed on in the food chain an..

Genetic Mutations
Chromosome Mutations – II

This tutorial is a continuation of the first lesson on chromosomal mutation. Here, find out the chromosomal aberrations ..

Birth Control and Contraception
Birth Control and Contraception

Different pregnancy and birth control and contraception strategies are described. Read this tutorial to learn each of th..

Bryophytes
Bryophytes

Bryophytes (nonvascular plants) are a plant group characterized by lacking vascular tissues. They include the mosses, th..