Information about Androgenic Hair
)
Distribution of androgenic hair on female and male body
Body hair, or more precisely androgenic hair, is a common term for the terminal hair on the human body developing during and after puberty in contrast to the head hair and the less visible vellus hair. The medical term androgenic hair refers to the fact that its growth depends on the level of androgens (male hormones) in the individual human organism. Due to a normally higher level of androgens men tend to have more androgenic hair than women so that this type of hair can be seen as a sign for sexual dimorphism and therefore a secondary sex characteristic.
From childhood onward, vellus hair covers the entire human body regardless of sex or race except in the following locations: the lips, the backs of the ears, the palms of hands, the soles of feet, certain external genital areas, the navel and scar tissue. The density of the hairs (in hair follicles per square centimeter) varies from one person to another.
Development and growth
The rising level of androgens due to puberty causes a transformation process of vellus hair into terminal hair on several parts of the human body. The hair follicles respond to androgens, primarily testosterone and its derivatives. The rate of hair growth and the weight of the hairs increase. Different areas respond with different sensitivities. As testosterone levels increase, the sequence of appearance of androgenic hair reflects the gradations of androgen sensitivity. The pubic area is most sensitive, and heavier hair usually grows there first in response to androgens.)
Areas on the human body that develop terminal hair growth due to rising androgens in both sexes, are the axillary hair and the pubic hair. In contrast to that, normally only men grow androgenic hair in other areas. There is a sexual dimorphism in the amount and distribution of androgenic hair, with males having more terminal hair (particularly facial hair, chest hair, abdominal hair, leg and arm hair) and females having more vellus hair, which is less visible. The genetic disposition determines the sex-dependent and individual rising of androgens and therefore the development of androgenic hair.
Evolution
){kind=small}
Human androgenic hair is the remnant of body hair of the type found in all other great apes, which was lost in the course of the history of the Homo genus (human evolution) roughly 3-2 million years ago. Loss of body hair is coupled to the evolution of dark skin colour, which was complete by 1.2 million years ago, judging from the numbers and spread of variations among human and chimpanzee MC1R nucleotide sequences.
Terminal hair is developed hair, which is generally longer, coarser, thicker and darker than the shorter and finer vellus hair. Phases of growth in it are more apparent than in vellus hair; it generally has a longer anagen phase.
..... Click the link for more information.
..... Click the link for more information.
The human body is the entire physical structure of a human organism. The human body consists of a head, neck, torso, two arms and two legs. The average height of an adult human is about 1.6 m (5 to 6 feet) tall. This size is largely determined by genes.
..... Click the link for more information.
..... Click the link for more information.
Puberty refers to the process of physical changes by which a child's body becomes an adult body capable of reproduction. Puberty is initiated by hormone signals from the brain to the gonads (the ovaries and testes).
..... Click the link for more information.
..... Click the link for more information.
Hair is a filamentous outgrowth of protein, found only on mammals. It projects from the epidermis, though it grows from hair follicles deep in the dermis. Although many other organisms, especially insects, show filamentous outgrowths, these are not considered "hair".
..... Click the link for more information.
..... Click the link for more information.
Vellus hair is short, fine, "peach fuzz" body hair. It is a very soft and short hair that grows in most places on the human body in both sexes. It is usually less than 2cm long and the follicles are not connected to sebaceous glands.
..... Click the link for more information.
..... Click the link for more information.
Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors.
..... Click the link for more information.
..... Click the link for more information.
hormone (from Greek όρμή - "to set in motion") is a chemical messenger that carries a signal from one cell (or group of cells) to another. All multicellular organisms produce hormones (including plants - see phytohormone).
..... Click the link for more information.
..... Click the link for more information.
man is a male human. The term man (irregular plural: men) is used for an adult human male, with the term boy being the usual term for a human male child or adolescent human male. However, man can refer to humanity as a whole.
..... Click the link for more information.
..... Click the link for more information.
worldwide view of the subject.
Please [ improve this article] or discuss the issue on the talk page.
Please [ improve this article] or discuss the issue on the talk page.
A woman is a female human. The term woman (irregular plural: women
..... Click the link for more information.
Sexual dimorphism is the systematic difference in form between individuals of different sex in the same species. Examples include size, color, and the presence or absence of parts of the body used in courtship displays or fights, such as ornamental feathers, horns, antlers or tusks.
..... Click the link for more information.
..... Click the link for more information.
Secondary sex characteristics are traits that distinguish the two sexes of a species, but that are not directly part of the reproductive system. Some have argued that in general they evolved to give an individual an advantage over its rivals in courtship.
..... Click the link for more information.
..... Click the link for more information.
This article is about the phase of human development known as childhood. For the Michael Jackson song, see Childhood (song).
Childhood (being a child
..... Click the link for more information.
Vellus hair is short, fine, "peach fuzz" body hair. It is a very soft and short hair that grows in most places on the human body in both sexes. It is usually less than 2cm long and the follicles are not connected to sebaceous glands.
..... Click the link for more information.
..... Click the link for more information.
Sex refers to the male and female duality of biology and reproduction. Unlike organisms that only have the ability to reproduce asexually, sexed male and female pairs have the ability to produce offspring through meiosis and fertilization.
..... Click the link for more information.
..... Click the link for more information.
RACE can refer to:
..... Click the link for more information.
- Research and Development in Advanced Communications Technologies in Europe, a program launched in 1988 by the Commission of the European Communities
- Rapid Amplification of cDNA Ends, a molecular biology technique
..... Click the link for more information.
The Project
Short description
LIPS (Linguistic and Intercultural Preparation of Students for the workplace) is a European Commission-funded project...... Click the link for more information.
outer ear is the most external portion of the ear. The outer ear includes the pinnae (also called auricle), the ear canal, and the very most superficial layer of the ear drum (also called the tympanic membrane).
..... Click the link for more information.
..... Click the link for more information.
The hands (med./lat.: manus, pl. manūs) are the two intricate, prehensile, multi-fingered body parts normally located at the end of each arm (medically: "terminating each anterior limb/appendage") of a human or other primate.
..... Click the link for more information.
..... Click the link for more information.
The foot is a biological structure found in many animals that is used for locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws or nails.
..... Click the link for more information.
..... Click the link for more information.
navel, also called a belly button, or umbilicus, is a scar on the abdomen, caused when the umbilical cord is removed from a newborn baby. All placental mammals have a navel.
..... Click the link for more information.
..... Click the link for more information.
Scars are areas of fibrous tissue that replace normal skin (or other tissue) after injury. A scar results from the biologic process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process.
..... Click the link for more information.
..... Click the link for more information.
Hair is a filamentous outgrowth of protein, found only on mammals. It projects from the epidermis, though it grows from hair follicles deep in the dermis. Although many other organisms, especially insects, show filamentous outgrowths, these are not considered "hair".
..... Click the link for more information.
..... Click the link for more information.
A hair follicle is part of the skin that grows hair by packing old cells together. Attached to the follicle is a sebaceous gland, a tiny sebum-producing gland found everywhere except on the palms, lips and soles of the feet.
..... Click the link for more information.
..... Click the link for more information.
square metre (also spelled meter, see spelling differences) is the SI derived unit of area, with symbol m². It is defined as the area of a square whose sides measure exactly one metre.
..... Click the link for more information.
..... Click the link for more information.
Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors.
..... Click the link for more information.
..... Click the link for more information.
Vellus hair is short, fine, "peach fuzz" body hair. It is a very soft and short hair that grows in most places on the human body in both sexes. It is usually less than 2cm long and the follicles are not connected to sebaceous glands.
..... Click the link for more information.
..... Click the link for more information.
Terminal hair is developed hair, which is generally longer, coarser, thicker and darker than the shorter and finer vellus hair. Phases of growth in it are more apparent than in vellus hair; it generally has a longer anagen phase.
..... Click the link for more information.
..... Click the link for more information.
A hair follicle is part of the skin that grows hair by packing old cells together. Attached to the follicle is a sebaceous gland, a tiny sebum-producing gland found everywhere except on the palms, lips and soles of the feet.
..... Click the link for more information.
..... Click the link for more information.
Testosterone is a steroid hormone from the androgen group. Testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands. It is the principal male sex hormone and an anabolic steroid.
..... Click the link for more information.
..... Click the link for more information.
Underarm hair (Axillary hair) is the composition of hair in the underarm area. This hair, as most of the other body hair, normally starts to appear at puberty and growth is usually complete by the end of teen age.
..... Click the link for more information.
..... Click the link for more information.
This article is copied from an article on Wikipedia.org - the free encyclopedia created and edited by online user community. The text was not checked or edited by anyone on our staff. Although the vast majority of the wikipedia encyclopedia articles provide accurate and timely information please do not assume the accuracy of any particular article. This article is distributed under the terms of GNU Free Documentation License.
Herod_Archelaus
