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Mini-puberty
Mini-puberty is a transient hormonal activation of the hypothalamic-pituitary-gonadal (HPG) axis that occurs in infants shortly after birth. This period is characterized by a surge in the secretion of gonadotropins ( LH and FSH) and sex steroids (testosterone in males and estradiol in females), similar to but less intense than the hormonal changes that occur in puberty during adolescence. Mini-puberty plays a crucial role in the early development of the reproductive system and the establishment of secondary sexual characteristics. Physiology Hypothalamic-pituitary-gonadal axis activation Mini-puberty begins within the first few days or weeks of life and typically lasts until 6–12 months of age. The HPG axis is temporarily reactivated, resulting in increased secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus. GnRH stimulates the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which in turn stimulate the go ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothalamic–pituitary–gonadal Axis
The hypothalamic–pituitary–gonadal axis (HPG axis, also known as the hypothalamic–pituitary–ovarian/testicular axis) refers to the hypothalamus, pituitary gland, and gonadal glands as if these individual endocrine glands were a single entity. Because these glands often act in concert, physiologists and endocrinologists find it convenient and descriptive to speak of them as a single system. The HPG axis plays a critical part in the development and regulation of a number of the body's systems, such as the reproductive and immune systems. Fluctuations in this axis cause changes in the hormones produced by each gland and have various local and systemic effects on the body. The axis controls development, reproduction, and aging in animals. Gonadotropin-releasing hormone (GnRH) is secreted from the hypothalamus by GnRH-expressing neurons. The anterior portion of the pituitary gland produces luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and the gonads produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovary
The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are endocrine glands, secreting various hormones that play a role in the menstrual cycle and fertility. The ovary progresses through many stages beginning in the prenatal period through menopause. Structure 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 ovaries are surrounded by a capsule, and have an outer cortex and an inner medulla. The capsule is of dense connect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Development Of The Endocrine System
The fetal endocrine system is one of the first systems to develop during prenatal development of a human individual. The endocrine system arises from all three embryonic germ layers. The endocrine glands that produce the steroid hormones, such as the gonads and adrenal cortex, arise from the mesoderm. In contrast, endocrine glands that arise from the endoderm and ectoderm produce the amine, peptide, and protein hormones. Adrenal glands The fetal adrenal cortex can be identified within four weeks of pregnancy. The adrenal cortex originates from the thickening of the intermediate mesoderm. At five to six weeks of gestation, the mesonephros differentiates into a tissue known as the gonadal ridge. The gonadal ridge produces the steroidogenic cells for both the gonads and the adrenal cortex. The adrenal medulla is derived from ectodermal cells. Cells that will become adrenal tissue move retroperitoneally to the upper portion of the mesonephros. At seven weeks of gestation, the adrena ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micropenis
A micropenis or microphallus is an unusually small Human penis, penis. A common criterion is a dorsal (measured on top) Human penis size, penile length of at least 2.5 standard deviations smaller than the mean human penis size for age. A micropenis is stretched penile length equal to or less than 1.9 Centimetre, cm (0.75 Inch, in) in term Infant, infants, and 9.3 cm (3.67 in) in adults. The condition is usually recognized shortly after Childbirth, birth. The term is most often used medically when the rest of the penis, scrotum, and perineum are without Ambiguous genitalia, ambiguity, such as hypospadias. Traditionally, a microphallus describes a micropenis with hypospadias. Micropenis incidence is about 1.5 in 10,000 male newborns in North America.ScienceDaily.com (2004).Surgeons Pinch More Than An Inch From The Arm To Rebuild A Micropenis" 6 Dec. 2004, retrieved 2 April 2012. Causes Of the abnormal conditions associated with micropenis, most are conditions of reduced prenata ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prostate Cancer
Prostate cancer is the neoplasm, uncontrolled growth of cells in the prostate, a gland in the male reproductive system below the bladder. Abnormal growth of the prostate tissue is usually detected through Screening (medicine), screening tests, typically blood tests that check for prostate-specific antigen (PSA) levels. Those with high levels of PSA in their blood are at increased risk for developing prostate cancer. Diagnosis requires a prostate biopsy, biopsy of the prostate. If cancer is present, the pathologist assigns a Gleason score; a higher score represents a more dangerous tumor. Medical imaging is performed to look for cancer that has spread outside the prostate. Based on the Gleason score, PSA levels, and imaging results, a cancer case is assigned a cancer staging, stage 1 to 4. A higher stage signifies a more advanced, more dangerous disease. Most prostate tumors remain small and cause no health problems. These are managed with active surveillance of prostate cancer, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breast Cancer
Breast cancer is a cancer that develops from breast tissue. Signs of breast cancer may include a Breast lump, lump in the breast, a change in breast shape, dimpling of the skin, Milk-rejection sign, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a red or scaly patch of skin. In those with Metastatic breast cancer, distant spread of the disease, there may be bone pain, swollen lymph nodes, shortness of breath, or yellow skin. Risk factors for developing breast cancer include obesity, a Sedentary lifestyle, lack of physical exercise, alcohol consumption, hormone replacement therapy during menopause, ionizing radiation, an early age at Menarche, first menstruation, having children late in life (or not at all), older age, having a prior history of breast cancer, and a family history of breast cancer. About five to ten percent of cases are the result of an inherited genetic predisposition, including BRCA mutation, ''BRCA'' mutations among others. Breast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycystic Ovary Syndrome
Polycystic ovary syndrome, or polycystic ovarian syndrome, (PCOS) is the most common endocrine disorder in women of reproductive age. The name is a misnomer, as not all women with this condition develop cysts on their ovaries. The name originated from the observation of cysts which form on the ovaries of some women with this condition. However, this is not a universal symptom and is not the underlying cause of the disorder. The primary characteristics of PCOS include hyperandrogenism, anovulation, insulin resistance, and neuroendocrinology, neuroendocrine disruption. Women may also experience Abnormal uterine bleeding, irregular menstrual periods, Menorrhagia, heavy periods, hirsutism, excess hair, acne, pelvic pain, infertility, difficulty getting pregnant, and patches of acanthosis nigricans, darker skin. Beyond its reproductive implications, PCOS is increasingly recognized as a multifactorial metabolic condition with significant long-term health consequences, including an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testicular Descent
The development of the gonads is part of the prenatal development of the reproductive system and ultimately forms the testicles in males and the ovaries in females. The immature ova originate from cells from the dorsal endoderm of the yolk sac. Once they have reached the gonadal ridge they are called oogonia. Development proceeds and the oogonia become fully surrounded by a layer of connective tissue cells (pre-granulosa cells). In this way, the rudiments of the ovarian follicles are formed. In the testicle, a network of tubules fuse to create the seminiferous tubules. Via the rete testis, the seminiferous tubules become connected with outgrowths from the mesonephros, which form the efferent ducts of the testicle. The descent of the testicles consists of the opening of a connection from the testis to its final location at the anterior abdominal wall, followed by the development of the gubernaculum, which subsequently pulls and translocates the testicle down into the developing s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anogenital Distance
Anogenital distance (AGD) is the distance from the midpoint of the anus to the genitalia, the underside of the vagina, the clitoris or the scrotum. It is considered medically significant for a number of reasons, in both humans and other animals, including sex determination and as a marker of endocrine disruptor exposure. It is regulated by dihydrotestosterone, which can be disrupted by phthalates common in plastics. The ''anogenital index'' (AGI) is an index used to compare the AGD relative to a model based on body weight. It is computed as the AGD divided by weight GI = AGD/weight (mm/kg) Measurement The AGD is usually measured as follows: from the center of the anus to the posterior convergence of the fourchette (where the vestibule begins) in females (AGD-AF); and from the center of the anus to the junction of the smooth perineal skin with the rugate skin of the scrotum in males (AGD-AS). An alternative measurement, AGD-AC, defined only in females, is measured from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phthalates
Phthalates ( ), or phthalate esters, are esters of phthalic acid. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften polyvinyl chloride (PVC). While phthalates are commonly used as plasticizers, not all plasticizers are phthalates. The two terms are specific, unique, and not used interchangeably. Lower-molecular-weight phthalates are typically replaced in many products in the United States, Canada, and European Union over health concerns. They are being replaced by higher molecular-weight phthalates as well as non-phthalic plasticizers. Phthalates are commonly ingested in small quantities via the diet. One of the most commonly known phthalates is bis(2-ethylhexyl) phthalate (DEHP). In many countries, DEHP is regulated as a toxin, and is banned from use in broad categories of consumer goods, such as cosmetics, children's toys, medical devices, and fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bisphenol A
Bisphenol A (BPA) is a chemical compound primarily used in the manufacturing of various plastics. It is a colourless solid which is Solubility, soluble in most common organic solvents, but has very poor solubility in water. BPA is produced on an industrial scale by the condensation reaction of phenol and acetone. Global production in 2022 was estimated to be in the region of 10 million tonnes. BPA's largest single application is as a co-monomer in the production of polycarbonates, which accounts for 65–70% of all BPA production. The manufacturing of epoxy resins and vinyl ester resins account for 25–30% of BPA use. The remaining 5% is used as a major component of several high-performance plastics, and as a minor additive in polyvinyl chloride (PVC), polyurethane, thermal paper, and several other materials. It is not a plasticizer, although it is often wrongly labelled as such. The health effects of BPA have been the subject of prolonged public and scientific debate. BPA is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pesticide
Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all pesticide use globally. Most pesticides are used as plant protection products (also known as crop protection products), which in general protect plants from weeds, fungi, or insects. In general, a pesticide is a chemical or biological agent (such as a virus, bacterium, or fungus) that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, cause nuisance, spread disease, or are disease vectors. Along with these benefits, pesticides also have drawbacks, such as potential toxicity to humans and other species. Definition The word pesticide derives from the Latin ''pestis'' (plagu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
