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Pubes
Pubic hair is terminal body hair that is found in the genital area 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. In the pubic region around the pubis bone, it is known as a ''pubic patch''. Pubic hair is also found on the scrotum in the male and on the vulva in the female. Although fine vellus hair is present in the area in childhood, pubic hair is considered to be the heavier, longer and coarser hair that develops during puberty as an effect of rising levels of androgens in males and estrogens in females. Pubic hair differs from other hair on the body and is a secondary sex characteristic. Many cultures regard pubic hair as erotic, and in most cultures it is associated with the genitals, which both men and women are expected to keep covered at all times. In some cultures, it is the norm for pubic hair to be removed, especially of females; the practice is regarded as part of persona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prepubescence
Preadolescence is a stage of human development following middle childhood and preceding adolescence.New Oxford American Dictionary. 2nd Edition. 2005. Oxford University Press. It commonly ends with the beginning of puberty. Preadolescence is commonly defined as ages 9–12 ending with the major onset of puberty. It may also be defined as simply the 2-year period before the major onset of puberty. Preadolescence can bring its own challenges and anxieties. Terminology A term used to refer to the preadolescent stage in everyday speech is tween and its perhaps older variants tweenie, tweeny, tweenager, and tweener. It's a blend (portmanteau) of the words "teen" and "between" in the sense of "between childhood and adolescence" and refers to 8-, 9-, or 10- to 12-year-olds. Sometimes the terms ''tweenie'' and ''tweenager'' are used to differentiate between older (10 to 15) and younger (7 to 11) age groups, respectively. While known as ''preadolescent'' in psychology, the terms ''pre ... [...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 girl, the testes in a boy. 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 boys and girls. Puberty leads to sexual dimorphism through the development of the secondary sex characteristics, which further distinguish the sexes. On average, girls begin puberty at ages 10–11 and complete puberty at ages 15–17; boys generally begin puberty at ages 11–12 and complete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beard
A beard is the hair that grows on the jaw, chin, upper lip, lower lip, cheeks, and neck of humans and some non-human animals. In humans, usually pubescent or adult males are able to grow beards. Throughout the course of history, societal attitudes toward male beards have varied widely depending on factors such as prevailing cultural-religious traditions and the current era's fashion trends. Some religions (such as some sects of Islam, and Sikhism) have considered a full beard to be essential and mandate it as part of their observance. Other cultures, even while not officially mandating it, view a beard as central to a man's virility, exemplifying such virtues as wisdom, strength, sexual prowess and high social status. In cultures where facial hair is uncommon (or currently out of fashion), beards may be associated with poor hygiene or an unconventional demeanor. In countries with colder climates, beards help protect the wearer's face from the elements. Beards also provide sun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estrogen
Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal activity: estrone (E1), estradiol (E2), and estriol (E3). Estradiol, an estrane, is the most potent and prevalent. Another estrogen called estetrol (E4) is produced only during pregnancy. Estrogens are synthesized in all vertebrates and some insects. Their presence in both vertebrates and insects suggests that estrogenic sex hormones have an ancient evolutionary history. Quantitatively, estrogens circulate at lower levels than androgens in both men and women. While estrogen levels are significantly lower in males than in females, estrogens nevertheless have important physiological roles in males. Like all steroid hormones, estrogens readily diffuse across the cell membrane. Once inside the cell, they bind to and activate estrogen receptors (E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Penis
The human penis is an external male intromittent organ that additionally serves as the urinary duct. The main parts are the root (radix); the body (corpus); and the epithelium of the penis including the shaft skin and the foreskin (prepuce) covering the glans penis. The body of the penis is made up of three columns of tissue: two corpora cavernosa on the dorsal side and corpus spongiosum between them on the ventral side. The human male urethra passes through the prostate gland, where it is joined by the ejaculatory duct, and then through the penis. The urethra traverses the corpus spongiosum, and its opening, the meatus (), lies on the tip of the glans penis. It is a passage both for urination and ejaculation of semen (''see'' male reproductive system.) Most of the penis develops from the same embryonic tissue as the clitoris in females. The skin around the penis and the urethra share the same embryonic origin as the labia minora in females. An erection is the stiffening e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pubarche
Pubarche refers to the first appearance of pubic hair at puberty. Pubarche is one of the physical changes of puberty and can occur independently of complete puberty. Pubarche usually results from rising levels of androgen and not estrogens in females, and androgens in males from the adrenal glands, ovaries, or testes but may also result from exposure to an anabolic steroid. When pubarche occurs prematurely (in early or mid-childhood), it is referred to as ''premature pubarche'' or precocious puberty and may warrant an evaluation. Premature adrenarche is the most common cause of premature pubarche. Early occurrences can arise due to congenital adrenal hyperplasia, androgen-producing tumors of the adrenals or gonads. When adrenarche, central puberty, and all pathologic conditions have been excluded, the term ''isolated premature pubarche'' is used to describe the unexplained development of pubic hair at an early age without other hormonal or physical changes of puberty. Average age ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Race (human Classification)
A race is a categorization of humans based on shared physical or social qualities into groups generally viewed as distinct within a given society. The term came into common usage during the 1500s, when it was used to refer to groups of various kinds, including those characterized by close kinship relations. By the 17th century, the term began to refer to physical (phenotypical) traits, and then later to national affiliations. Modern science regards race as a social construct, an identity which is assigned based on rules made by society. While partly based on physical similarities within groups, race does not have an inherent physical or biological meaning. The concept of race is foundational to racism, the belief that humans can be divided based on the superiority of one race over another. Social conceptions and groupings of races have varied over time, often involving folk taxonomies that define essential types of individuals based on perceived traits. Today, scientists con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eyebrows
An eyebrow is an area of short hairs above each eye that follows the shape of the lower margin of the brow ridges of some mammals. In humans, eyebrows serve two main functions: first, communication through facial expression, and second, prevention of sweat, water, and other debris from falling down into the eye socket. It is common for people to modify their eyebrows by means of hair removal and makeup. Functions A number of theories have been proposed to explain the function of the eyebrow in humans. One approach suggests its main function is to prevent moisture (mostly sweat and rain) from flowing into the eye. Another theory holds that clearly visible eyebrows provided safety from predators when early hominid groups started sleeping on the ground. Recent research, however, suggests eyebrows in humans developed as a means of communication and that this is their primary function. Humans developed a smooth forehead with visible, hairy eyebrows capable of a wide range of movemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underarm Hair
Underarm hair, also known as axillary hair, is the hair in the underarm area (''axilla''). Development Underarm or axillary hair goes through four stages of development, driven by weak androgens produced by the adrenal in males and females during adrenarche, and testosterone from the testicle in males during puberty. The importance of human underarm hair is unclear. It may naturally wick sweat or other moisture away from the skin, aiding ventilation. Colonization by odor-producing bacteria is thereby transferred away from the skin (see skin flora). File:Armpit by David Shankbone.jpg , Male axilla File:Womans armpit.JPG , Female axilla Function Reducing friction Armpit hair prevents skin-to-skin contact during activities that involve arm motion, such as running and walking. The same applies to pubic hair. Spreading pheromones The armpits release odor-containing pheromones, a naturally produced chemical that plays an important role in sexual attraction. Armpit hair tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testis
A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testosterone. Testosterone release is controlled by the anterior pituitary luteinizing hormone, whereas sperm production is controlled both by the anterior pituitary follicle-stimulating hormone and gonadal testosterone. Structure Appearance Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry, in which one testicle extends farther down into the scrotum than the other, is common. This is because of the differences in the vasculature's anatomy. For 85% of men, the right testis hangs lower than the left one. Measurement and volume The volume of the testicle can be estimated by palpating it and comparing it to ellipsoids of known sizes. Another method is to use caliper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovary
The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. The ovaries also secrete hormones that play a role in the menstrual cycle and fertility. The ovary progresses through many stages beginning in the prenatal period through menopause. It is also an endocrine gland because of the various hormones that it secretes. Structure The ovaries are considered the female gonads. Each ovary is whitish in color and located alongside the lateral wall of the uterus in a region called the ovarian fossa. The ovarian fossa is the region that is bounded by the external iliac artery and in front of the ureter and the internal iliac artery. This area is about 4 cm x 3 cm x 2 cm in size.Daftary, Shirish; Chakravarti, Sudip (2011). Manual of Obstetrics, 3rd Edition. Elsevier. pp. 1-16. . The ovari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonad
A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sperm in the form of spermatozoa. The female gonad, the ovary, produces egg cells. Both of these gametes are haploid cells. Some hermaphroditic animals have a type of gonad called an ovotestis. Evolution It is hard to find a common origin for gonads, but gonads most likely evolved independently several times. Regulation The gonads are controlled by luteinizing hormone and follicle-stimulating hormone, produced and secreted by gonadotropes or gonadotrophins in the anterior pituitary gland. This secretion is regulated by gonadotropin-releasing hormone produced in the hypothalamus. Development Gonads start developing as a common primordium (an organ in the earliest stage of development), in the form of genital ridges, which are only l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
