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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] |
Precocious Puberty
In medicine, precocious puberty is puberty occurring at an unusually early age. In most cases, the process is normal in every aspect except the unusually early age and simply represents a variation of normal development. In a minority of children with precocious puberty, the early development is triggered by a disease such as a tumor or injury of the brain. Even when there is no disease, unusually early puberty can have adverse effects on social behavior and psychological development, can reduce adult height potential, and may shift some lifelong health risks. Central precocious puberty can be treated by suppressing the pituitary hormones that induce sex steroid production. The opposite condition is delayed puberty. The term is used with several slightly different meanings that are usually apparent from the context. In its broadest sense, and often simplified as early puberty, "precocious puberty" sometimes refers to any physical sex hormone effect, due to any cause, occurring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menarche
Menarche ( ; ) is the first menstrual cycle, or first menstrual bleeding, in female humans. From both social and medical perspectives, it is often considered the central event of female puberty, as it signals the possibility of fertility. Girls experience menarche at different ages. Having menarche occur between the ages of 9–16 in the west is considered normal.US National Health Statistics Report September 2020 Canadian psychological researcher Niva Piran claims that menarche or the perceived average age of puberty is used in many cultures to separate girls from activity with boys, and to begin confinement as a woman and future wife. The timing of menarche is influenced by female , as we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Development (biology)
Development of the human body is the process of growth to maturity. The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through mitosis and cell differentiation, and the resulting embryo then implants in the uterus, where the embryo continues development through a fetal stage until birth. Further growth and development continues after birth, and includes both physical and psychological development, influenced by genetic, hormonal, environmental and other factors. This continues throughout life: through childhood and adolescence into adulthood. Before birth Development before birth, or prenatal development () is the process in which a zygote, and later an embryo and then a fetus develops during gestation. Prenatal development starts with fertilization and the formation of the zygote, the first stage in embryonic development which continues in fetal develo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenoestrogen
Xenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have estrogenic effects on a living organism even though they differ chemically from the estrogenic substances produced internally by the endocrine system of any organism. Natural xenoestrogens include phytoestrogens which are plant-derived xenoestrogens. Because the primary route of exposure to these compounds is by consumption of phytoestrogenic plants, they are sometimes called "dietary estrogens". Mycoestrogens, estrogenic substances from fungi, are another type of xenoestrogen that are also considered mycotoxins. Xenoestrogens are clinically significant because they can mimic the effects of endogenous estrogen and thus have been implicated in precocious puberty and other disorders of the reproductive system. Xenoestrogens include pharmacolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Body
The human body is the structure of a Human, human being. It is composed of many different types of Cell (biology), cells that together create Tissue (biology), tissues and subsequently organ systems. They ensure homeostasis and the life, viability of the human body. It comprises a human head, head, hair, neck, Trunk (anatomy), trunk (which includes the thorax and abdomen), arms and hands, human leg, legs and feet. The study of the human body involves anatomy, physiology, histology and embryology. The body anatomical variability, varies anatomically in known ways. Physiology focuses on the systems and organs of the human body and their functions. Many systems and mechanisms interact in order to maintain homeostasis, with safe levels of substances such as sugar and oxygen in the blood. The body is studied by health professionals, physiologists, anatomists, and by artists to assist them in their work. Composition The composition of the human body, human body is composed of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermarche
Spermarche—also known as semenarche—is the beginning of development of sperm in boys' testicles at puberty.''Adolescence and Emerging Adulthood: A Cultural Approach'', Jeffrey Jensen Arnett, N.J.: Prentice-Hall, 3rd edition, 2006. It is the counterpart of menarche in girls. Depending on their upbringing, cultural differences, and prior sexual knowledge, boys may have different reactions to spermarche, ranging from fear to excitement. Spermarche is one of the first events in the life of a male leading to sexual maturity. It occurs at the time when the secondary sex characteristics are just beginning to develop. The age when spermarche occurs is not easy to determine. However, researchers have tried to determine the age in various populations by taking urine samples of boys and determining the presence of spermatozoa. The presence of sperm in urine is referred to as spermaturia. Age of occurrence ''1986 Year Book of Pediatrics'' stated "Fish irsch - n.n.et al. (J. Adolesc. H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Libido
Libido (; colloquial: sex drive) is a person's overall sexual drive or desire for sexual activity. Libido is influenced by biological, psychological, and social factors. Biologically, the sex hormones and associated neurotransmitters that act upon the nucleus accumbens (primarily testosterone and dopamine, respectively) regulate libido in humans. Social factors, such as work and family, and internal psychological factors, such as personality and stress, can affect libido. Libido can also be affected by medical conditions, medications, lifestyle and relationship issues, and age (e.g., puberty). A person who has extremely frequent sexual urges, or a suddenly increased sex drive may be experiencing hypersexuality, while the opposite condition is hyposexuality. In psychoanalytic theory, libido is psychic drive or energy, particularly associated with sexual instinct, but also present in other instinctive desires and drives. A person may have a desire for sex, but not have the opportu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most animals and some plants. Differences may include secondary sex characteristics, size, weight, colour, markings, or behavioural or cognitive traits. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', which is when both biological sexes are phenotypically indistinguishable from each other. Overview Ornamentation and coloration Common and easily identified types of dimorphism consist of ornamentation and coloration, though not always apparent. A difference in coloration of sexes within a given species is called sexual dichromatism, which is commonly seen in many species of birds and reptiles. Sexual selection leads to the exaggerated dim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breast
The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues. In females, it serves as the mammary gland, which produces and secretes milk to feed infants. Subcutaneous fat covers and envelops a network of ducts that converge on the nipple, and these tissues give the breast its size and shape. At the ends of the ducts are lobules, or clusters of alveoli, where milk is produced and stored in response to hormonal signals. During pregnancy, the breast responds to a complex interaction of hormones, including estrogens, progesterone, and prolactin, that mediate the completion of its development, namely lobuloalveolar maturation, in preparation of lactation and breastfeeding. Humans are the only animals with permanent breasts. At puberty, estrogens, in conjunction with growth hormone, cause permanent breast growth in female humans. This happens only to a much lesser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pediatrics (journal)
''Pediatrics'' is a peer-reviewed medical journal published by the American Academy of Pediatrics. In the inaugural January 1948 issue, the journal's first editor-in-chief, Hugh McCulloch, articulated the journal's vision: "The content of the journal is... intended to encompass the needs of the whole child in his physiologic, mental, emotional, and social structure. The single word, Pediatrics, has been chosen to indicate this catholic intent." ''Pediatrics'' has been continuously published by the American Academy of Pediatrics since January 1948. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor of 7.124, ranking it fourth out of 119 journals in the category "Pediatrics". Editors The following persons have been editor-in-chief of ''Pediatrics'': *1948–1954 Hugh McCulloch *1954–1961 Charles D. May *1962–1974 Clement A. Smith *1974–2009 Jerold F. Lucey *2009–present Lewis First Lewis may refer to: Names * Lewis (given name), includi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocrine Disruptor
Endocrine disruptors, sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds are chemicals that can interfere with endocrine (or hormonal) systems. These disruptions can cause cancerous tumors, birth defects, and other developmental disorders. Found in many household and industrial products, endocrine disruptors "interfere with the synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body that are responsible for development, behavior, fertility, and maintenance of homeostasis (normal cell metabolism)." Any system in the body controlled by hormones can be derailed by hormone disruptors. Specifically, endocrine disruptors may be associated with the development of learning disabilities, severe attention deficit disorder, cognitive and brain development problems. There has been controversy over endocrine disruptors, with some groups calling for swift action by regulators to re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Daily Telegraph
''The Daily Telegraph'', known online and elsewhere as ''The Telegraph'', is a national British daily broadsheet newspaper published in London by Telegraph Media Group and distributed across the United Kingdom and internationally. It was founded by Arthur B. Sleigh in 1855 as ''The Daily Telegraph & Courier''. Considered a newspaper of record over ''The Times'' in the UK in the years up to 1997, ''The Telegraph'' generally has a reputation for high-quality journalism, and has been described as being "one of the world's great titles". The paper's motto, "Was, is, and will be", appears in the editorial pages and has featured in every edition of the newspaper since 19 April 1858. The paper had a circulation of 363,183 in December 2018, descending further until it withdrew from newspaper circulation audits in 2019, having declined almost 80%, from 1.4 million in 1980.United Newspapers PLC and Fleet Holdings PLC', Monopolies and Mergers Commission (1985), pp. 5–16. Its si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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