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| Anatomical terminology |
A mammary alveolus (pl.: alveoli, from Latin alveolus, "little cavity") is a small cavity or sac found in the mammary gland. [1] [2] Mammary alveoli are the site of milk production and storage in the mammary gland. [1] [2] Mammary alveoli cluster into groups called mammary lobules, and each breast may contain 15 to 20 of these lobules. [1] [2] The lobules drain milk through the lactiferous ducts out of the nipples. [1] [2]
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.
A pulmonary alveolus, also known as an air sac or air space, is one of millions of hollow, distensible cup-shaped cavities in the lungs where pulmonary gas exchange takes place. Oxygen is exchanged for carbon dioxide at the blood–air barrier between the alveolar air and the pulmonary capillary. Alveoli make up the functional tissue of the mammalian lungs known as the lung parenchyma, which takes up 90 percent of the total lung volume.
The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa.
A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word mamma, "breast". The mammary glands are arranged in organs such as the breasts in primates, the udder in ruminants, and the dugs of other animals. Lactorrhea, the occasional production of milk by the glands, can occur in any mammal, but in most mammals, lactation, the production of enough milk for nursing, occurs only in phenotypic females who have gestated in recent months or years. It is directed by hormonal guidance from sex steroids. In a few mammalian species, male lactation can occur. With humans, male lactation can occur only under specific circumstances.
An udder is an organ formed of two or four mammary glands on the females of dairy animals and ruminants such as cattle, goats, and sheep. An udder is equivalent to the breast in primates and elephantine pachyderms. The udder is a single mass hanging beneath the animal, consisting of pairs of mammary glands with protruding teats. In cattle, camels and deer, there are normally two pairs, in sheep and goats, there is one pair, and in some animals, there are many pairs. In animals with udders, the mammary glands develop on the milk line near the groin, and mammary glands that develop on the chest are generally referred to as breasts.
Mouse mammary tumor virus (MMTV) is a milk-transmitted retrovirus like the HTL viruses, HI viruses, and BLV. It belongs to the genus Betaretrovirus. MMTV was formerly known as Bittner virus, and previously the "milk factor", referring to the extra-chromosomal vertical transmission of murine breast cancer by adoptive nursing, demonstrated in 1936, by John Joseph Bittner while working at the Jackson Laboratory in Bar Harbor, Maine. Bittner established the theory that a cancerous agent, or "milk factor", could be transmitted by cancerous mothers to young mice from a virus in their mother's milk. The majority of mammary tumors in mice are caused by mouse mammary tumor virus.
Milk is a nutrient liquid produced by the mammary glands of mammals.
The abortion–breast cancer hypothesis posits that having an induced abortion can increase the risk of getting breast cancer. This hypothesis is at odds with mainstream scientific opinion and is rejected by major medical professional organizations; despite this, it continues to be widely propagated as pseudoscience, typically in service of an anti-abortion agenda.
Alveolus is a general anatomical term for a concave cavity or pit.
Dental alveoli are sockets in the jaws in which the roots of teeth are held in the alveolar process with the periodontal ligament. The lay term for dental alveoli is tooth sockets. A joint that connects the roots of the teeth and the alveolus is called gomphosis. Alveolar bone is the bone that surrounds the roots of the teeth forming bone sockets.
The mammary ridge or mammary crest is a primordium specific for the development of mammary glands.
Lactiferous ducts are ducts that converge and form a branched system connecting the nipple to the lobules of the mammary gland. When lactogenesis occurs, under the influence of hormones, the milk is moved to the nipple by the action of smooth muscle contractions along the ductal system to the tip of the nipple. They are also referred to as galactophores, galactophorous ducts, mammary ducts, mamillary ducts or milk ducts.
Amastia refers to a rare clinical anomaly in which both internal breast tissue and the visible nipple are absent on one or both sides. It affects both men and women. Amastia can be either isolated or comorbid with other syndromes, such as ectodermal dysplasia, Syndactyly and lipoatrophic diabetes. This abnormality can be classified into various types, and each could result from different pathologies. Amastia differs from amazia and athelia. Amazia is the absence of one or both mammary glands but the nipples remain present, and athelia is the absence of one or both nipples, but the mammary gland remains.
Ptosis or sagging of the female breast is a natural consequence of aging. The rate at which a woman's breasts drop and the degree of ptosis depends on many factors. The key factors influencing breast ptosis over a woman's lifetime are cigarette smoking, her number of pregnancies, higher body mass index, larger bra cup size, and significant weight change. Post-menopausal women or people with collagen deficiencies may experience increased ptosis due to a loss of skin elasticity. Many women and medical professionals mistakenly believe that breastfeeding increases sagging. It is also commonly believed that the breast itself offers insufficient support and that wearing a bra prevents sagging, which has not been found to be true.
In anatomy, a lobe is a clear anatomical division or extension of an organ that can be determined without the use of a microscope at the gross anatomy level. This is in contrast to the much smaller lobule, which is a clear division only visible under the microscope.
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The process of feeding milk in all female creatures is called nursing, and in humans it is also called breastfeeding. Newborn infants often produce some milk from their own breast tissue, known colloquially as witch's milk.
Breast development, also known as mammogenesis, is a complex biological process in primates that takes place throughout a female's life.
Mother's milk is milk produced by mammary glands located in the breast of a human female to feed a young child.
The hypothalamic–pituitary–prolactin axis, also known as the hypothalamic–pituitary–mammary axis or hypothalamic–pituitary–breast axis, is a hypothalamic–pituitary axis which includes the secretion of prolactin from the lactotrophs of the pituitary gland into the circulation and the subsequent action of prolactin on tissues such as, particularly, the mammary glands or breasts. It is involved in lobuloalveolar maturation of the mammary glands during pregnancy and the induction and maintenance of lactation following parturition. Hormones that control the secretion of prolactin from the pituitary gland include dopamine, estradiol, progesterone, thyrotropin-releasing hormone (TRH), and vasoactive intestinal peptide (VIP).
Establishment of breastfeeding refers to the initiation of providing breast milk of mother to baby. According to the World Health Organisation(WHO), breastfeeding is the best way to provide nourishment, including essential nutrients, energy and antibodies, to infants and toddlers. The start of breastfeeding is supported by the milk production which depends on the development of internal and external breast structure and hormonal control on milk secretion. Besides milk supply, adopting the correct approach of breastfeeding helps build up the maternal bond, which in turn promotes breastfeeding. Not only does nursing strengthen the mother-child relationship, but it also improves the intelligence and immunity of breastfed children and diminishes breastfeeding mothers' risks to have ovarian and breast cancer.
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