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...

Carbohydrates, fats and proteins - dietary sources
A Balanced Diet – Carbohydrates and Fat

Apart from vitamins, the human body also requires high energy sources such as carbohydrates and fats. If you want an ove..

Direct and indirect physiologic effects of growth hormone
Animal Growth Hormones

Hormones are produced in the endocrine glands of animals. The pituitary gland and hypothalamus are the most impor..

Human Nervous System
The Human Nervous System

The nervous system is essentially a biological information highway. This tutorial gives an overview of the nervous syste..

Consciousness and behavior
Consciousness and Behavior

Human consciousness and behavior are an interesting topic since they are determined and controlled by the brain. Conscio..

Physical growth
Physical Development in Humans

This tutorial elaborates on the physical development of humans, particularly from puberty to adulthood. Read this tutori..

Sigmund Freud and Carl Gustav Jung
Sigmund Freud and Carl Gustav Jung

In this tutorial, the works of Carl Gustav Jung and Sigmund Freud are described. Both of them actively pursued the way h..

Related Articles...

No related articles found

See all Related Topics