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Terminal Hair
In humans, terminal hair is a variant of hair that is thick and long such as that growing on the scalp, as compared with vellus hair, colloquially known as peach fuzz, growing elsewhere.Marks, James G; Miller, Jeffery (2006)''Lookingbill and Marks' Principles of Dermatology''(4th ed.), Elsevier Inc., p. 11. During puberty, the increase in androgenic hormone levels causes vellus hair to be replaced with terminal hair in certain parts of the human body.Hiort, O. "Androgens and Puberty". ''Best Practice & Research Clinical Endocrinology & Metabolism'', Vol. 16, No. 1, pp. 31–41. These parts will have different levels of sensitivity to androgens, primarily of the testosterone family.Neal, Matthew; Lauren M. Sompayrac''How the Endocrine System Works'' Blackwell Publishing, 2001, p. 75. The pubic area is particularly sensitive to such hormones, as are the armpits which will develop axillary hair.Randall, Valerie A.; Nigel A. Hibberts, M. Julie Thornton, Kazuto Hamada, Alison E. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vellus Hair
Vellus hair is short, thin, light-colored, and barely noticeable hair that develops on most of a human's body during childhood. Exceptions include the lips, the back of the ear, the palm of the hand, the sole of the foot, some external genital areas, the navel, and scar tissue. The density of hair – the number of hair follicles per area of skin – varies from person to person. Each strand of vellus hair is usually less than 2 mm (1/13 inch) long and the follicle is not connected to a sebaceous gland. Vellus hair is most easily observed on children and adult women, who generally have less terminal hair to obscure it. Vellus hair is not lanugo hair. Lanugo hair is a much thicker type of hair that normally grows only on fetuses. Vellus hair is differentiated from the more visible terminal or androgenic hair, which develops only during and after puberty, usually to a greater extent on men than it does on women. The Latin language uses the word ''vellus'' to designate "a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puberty
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a female, the testicles in a male. In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the brain, bones, muscle, blood, skin, hair, breasts, and sex organs. Physical growth—height and weight—accelerates in the first half of puberty and is completed when an adult body has been developed. Before puberty, the external sex organs, known as primary sexual characteristics, are sex characteristics that distinguish males and females. Puberty leads to sexual dimorphism through the development of the secondary sex characteristics, which further distinguish the sexes. On average, females begin puberty at age 10½ and complete puberty at ages 15-17; males begin at ages 11½-12 and complete pube ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pubic Hair
Pubic hair (or pubes , ) is terminal hair, terminal body hair that is found in the sex organ, genital area and pubic region of adolescent and adult humans. The hair is located on and around the sex organs, and sometimes at the top of the inside of the thighs, even extending down the perineum, and to the Anus, anal region. Pubic hair is also found on the scrotum and base of the Body of penis, penile shaft (in males) and on the vulva (in females). Around the Pubis (bone), pubis bone and the mons pubis that covers it, it is known as a ''pubic patch'', which can be styled. Although fine vellus hair is present in the area during childhood, pubic hair is considered to be the heavier, longer, coarser hair that develops during puberty as an effect of rising levels of hormones: androgens in males and estrogens in females. Many cultures regard pubic hair as erotic, and most cultures associate it with the genitals, which people are expected to keep covered at all times. In some cultures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axillary Hair
Underarm hair, also known as axillary hair or armpit hair, is the hair in the underarm area (''axilla''). Development Underarm or axillary hair goes through four stages of development, as staged by the Wolfsdorf Axillary Hair Scale, driven by weak androgens produced by the adrenal in males and females during adrenarche, and testosterone from the testicle in males during puberty. The Wolfsdorf Axillary Hair Staging system provides a standardized method for assessing pubertal progression and androgenic activity in pediatric populations. Similar to Tanner scale, Tanner Staging for pubic hair, it classifies axillary hair growth into four stages: * Wolfsdorf Stage 1 – No axillary hair * Wolfsdorf Stage 2 – Sparse, soft hair * Wolfsdorf Stage 3 – Coarser hair with increased volume * Wolfsdorf Stage 4 – Full adult-like axillary hair The importance of human underarm hair is unclear. It may naturally wick perspiration, sweat or other moisture away from the skin, aiding ventila ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Sex Characteristic
A secondary sex characteristic is a physical characteristic of an organism that is related to or derived from its sex, but not directly part of its reproductive system. In humans, these characteristics typically start to appear during puberty—and include enlarged breasts and widened hips of females, facial hair and Adam's apples on males, and pubic hair on both. In non-human animals, they can start to appear at sexual maturity—and include, for example, the manes of male lions, the bright facial and rump coloration of male mandrills, and horns in many goats and antelopes. Secondary sex characteristics are particularly evident in the sexually dimorphic phenotypic traits that distinguish the sexes of a species. In evolution, secondary sex characteristics are the product of sexual selection for traits that show fitness, giving an organism an advantage over its rivals in courtship and in aggressive interactions. Many characteristics are believed to have been establishe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facial Hair
Facial hair is hair grown on the face, usually on the chin, cheeks, bottom lip and upper lip region. It is typically a secondary sex characteristic of human males. Men typically start developing facial hair in the later stages of puberty or adolescence, at around fourteen years of age, and most do not finish developing a full adult beard until around sixteen or later. However, large variations can occur; boys as young as ten have also been known to develop facial hair, and some men do not produce much facial hair at all. Men may style their facial hair into beards, moustaches, goatees or sideburns; many others completely shave their facial hair and this is referred to as being "clean-shaven". The term ''whiskers'', when used to refer to human facial hair, indicates the hair on the chin and cheeks. Women are also capable of developing facial hair, especially after menopause, though typically significantly less than men. Women with lots of facial hair, the extreme being bear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chest Hair
Chest hair is hair that grows on the chest in the region between the neck and the abdomen. Chest hair develops during and after puberty along with other types of androgenic hair. Development and growth Although vellus hair is already present in the area in childhood, chest hair is the terminal hair that develops as an effect of rising levels of androgens (primarily testosterone and its derivatives) due to puberty. Different from the head hair, it is therefore a secondary sexual characteristic. Men tend to be covered with far more terminal hair, particularly on the chest, the abdomen, and the face. The development of chest hair begins normally during late puberty, usually between the ages of 12 and 18. It can also start later, between the age of 20 and 30, so that many men in their twenties have not yet reached their full chest hair development. The growth continues subsequently. Patterns and characteristics The individual occurrence and characteristics of chest hair depend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abdominal Hair
Abdominal hair is the hair that grows on the abdomen of humans and non-human mammals, in the region between the pubic area and the thorax (chest). The growth of abdominal hair follows the same pattern on nearly all mammals, vertically from the pubic area upwards and from the thorax downwards to the navel. The abdominal hair of non-human mammals is part of the pelage, (hair or fur). It connects pubic hair and chest hair. In humans Before puberty, the abdominal region of both males and females is covered with very fine vellus hair. In response to rising levels of androgens (mainly dihydrotestosterone) during and after puberty, the skin of the abdomen begins to produce coarser, longer and more pigmented hair (terminal hair). This process primarily affects men. Initially, hair grows in a vertical line from the pubic area up to the navel and from the thorax down to the navel. The development of abdominal hair normally begins in the final stages of puberty. With some men, the abdom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leg Hair
Leg hair is hair that grows on the legs of humans, generally appearing after the onset of puberty. For aesthetic reasons and for some sports, people shave, wax, epilate, or use hair removal creams to remove the hair from their legs: see leg shaving. The current Guinness World Record for world's longest leg hair belongs to Jason Allen of Tucson, Arizona at 8.84 inches (22.46 cm). Growth The real action of leg hair takes place below the skin or the epidermis. The cells that are in the hair follicles divide and multiply. When the space fills up in the follicle it pushes older cells out and that is what becomes the leg hair. After the older cells become hard and leave the follicle, they form a hair shaft. The hair shaft is mostly made up of dead tissue and a protein that is known as keratin. It is said that hair growth occurs during the "growing" phase of the follicle, and then retained as dead club hair during the "resting" phase. The old club hair might be lost withi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arm Hair
Body hair or androgenic hair is terminal hair that develops on the human body during and after puberty. It is different from head hair and also from less visible vellus hair, which is much finer and lighter in color. Growth of androgenic hair is related to the level of androgens (male hormones) and the density of androgen receptors in the dermal papillae. Both must reach a threshold for the proliferation of hair follicle cells. From childhood onward, regardless of sex, vellus hair covers almost the entire area of the human body. Exceptions include the lips, the backs of the ears, palms of hands, soles of the feet, certain external genital areas, the navel, and scar tissue. Density of hair – i.e. the number of hair follicles per unit area of skin – varies from person to person. In many cases, areas on the human body that contain vellus hair will begin to produce darker and thicker body hair during puberty, such as the first growth of beard hair on a male and female adolesc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foot Hair
Body hair or androgenic hair is terminal hair that develops on the human body during and after puberty. It is different from head hair and also from less visible vellus hair, which is much finer and lighter in color. Growth of androgenic hair is related to the level of androgens (male hormones) and the density of androgen receptors in the dermal papillae. Both must reach a threshold for the proliferation of hair follicle cells. From childhood onward, regardless of sex, vellus hair covers almost the entire area of the human body. Exceptions include the lips, the backs of the ears, palms of hands, soles of the feet, certain external genital areas, the navel, and scar tissue. Density of hair – i.e. the number of hair follicles per unit area of skin – varies from person to person. In many cases, areas on the human body that contain vellus hair will begin to produce darker and thicker body hair during puberty, such as the first growth of beard hair on a male and female adole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
