Mammary glands are the organs In biology and anatomy, an organ is a tissue that performs a specific function or group of functions within an organism that, in mammals Mammals are a class of vertebrate animals whose females are characterized by the possession of mammary glands while both males and females are characterized by sweat glands, hair, three middle ear bones used in hearing, and a neocortex region in the brain, produce milk Milk is an opaque white liquid produced by the mammary glands of mammals . It provides the primary source of nutrition for newborn mammals before they are able to digest other types of food. The early lactation milk is known as colostrum, and carries the mother's antibodies to the baby. It can reduce the risk of many diseases in the baby. The for the sustenance of the young. These exocrine glands Exocrine glands are glands that secrete their products into ducts (duct glands). They are the counterparts to endocrine glands, which secrete their products (hormones) directly into the bloodstream (ductless glands) or release hormones (paracrines) that affect only target cells nearby the release site are enlarged and modified sweat glands 1. Hair Shaft 2. Stratum Corneum 3. Pigment Layer 4. Stratum Spinosum 5. Stratum Basale 6. Arrector Pili Muscle 7. Sebaceous Gland 8. Hair Follicle 9. Papilla of Hair 10. Nerve Fiber 11. Sweat Gland 12. Pacinian Corpuscle 13. Artery 14. Vein 15. Sensory Nerve ending 16. Dermal Papillary 17. Sweat Pore and give mammals their name. The mammary glands of domestic mammals containing more than two breasts are called dugs.

Contents

Humans

Main article: Breast

Structure

The basic components of a mature mammary gland are the alveoli (hollow cavities, a few millimetres large) lined with milk-secreting cuboidal cells Cuboidal epithelia are epithelial cells having a cube-like shape; that is, their width is approximately equal to their height. They may exist in single layers or multiple layers (stratified cuboidal epithelium) depending on their location (and thus function) in the body and surrounded by myoepithelial cells. These alveoli join up to form groups known as lobules, and each lobule has a lactiferous duct that drains into openings in the nipple. The myoepithelial cells can contract under the stimulation of oxytocin Oxytocin is a mammalian hormone that also acts as a neurotransmitter in the brain thereby excreting milk secreted from alveolar units into the lobule lumen toward the nipple, where it collects in sinuses of the ducts. As the infant begins to suck, the hormonally (oxytocin) mediated "let down reflex" ensues and the mother's milk is secreted into – not sucked from the gland by – the baby's mouth.

All the milk-secreting tissue leading to a single lactiferous duct is called a "simple mammary gland"; a "complex mammary gland" is all the simple mammary glands serving one nipple. Humans normally have two complex mammary glands, one in each breast, and each complex mammary gland consists of 10–20 simple glands. The presence of more than two nipples is known as polythelia and the presence of more than two complex mammary glands as polymastia.

To keep the correct polarized morphology of the lactiferous duct tree requires another essential component - mammary epithelial cells extracellular matrix In biology, the extracellular matrix is the extracellular part of animal tissue that usually provides structural support to the animal cells in addition to performing various other important functions. The extracellular matrix is the defining feature of connective tissue in animals (ECM), which together with adipocytes Adipocytes are the cells that primarily compose adipose tissue, specialized in storing energy as fat, fibroblast A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework for animal tissues, and play a critical role in wound healing. They are the most common cells of connective tissue in animals, inflammatory cells etc. constitute mammary stroma[1]. Mammary epithelial ECM mainly contains myoepithelial basement membrane The basement membrane is a sheet of cells and fibers that underlies two other kinds of cells -- the epithelium, which lines the cavities and surfaces of organs, and the endothelium, which lines the interior surface of blood vessels and the connective tissue. They not only help to support mammary basic structure, but also serve as a communicating bridge between mammary epithelials and their local and global environment throughout this organ's development[2].

Development and hormonal control

Mammary glands develop all along during different growth cycles. They exist in both sexes during embryonic stage, forming only a rudimentary duct tree at birth. In this stage, mammary gland development is systemic hormone independent [3], but under the regulation of paracrine communication between neighboring epithelial and mesenchymal cells by parathyroid hormone-related protein(PTHrP)[4]. This local secreted factor gives rise to a series of outside-in and inside-out positive feedback between these two types of cells, so that mammary bud epithelial cells can get to proliferate and sprout down into the mesenchymal layer until they reach the fat pad to begin the first round of branching[5]. At the same time, the embryonic mesenchymal cells around the epithelial bud get secrecting factors activated by PTHrP, such as BMP4, can transform into a dense, mammary-specific mesenchyme, which later develop into connective tissue with fibrous threads, forming blood vessels and the lymph system[6]. Basement membrane, mainly containing laminin Laminin is a protein found in the extracellular matrix, the sheets of protein that form the substrate of all internal organs also called the basement membrane. It is the major non-collagenous component of the basal lamina, such as those on which cells of an epithelium sit. It has four arms that can bind to four other molecules. The three shorter and collagen Collagen is the main protein of connective tissue in animals and the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content. It is naturally found exclusively in metazoa, including sponges. In muscle tissue it serves as a major component of endomysium. Collagen constitutes 1% to 2% of muscle tissue, and, formed thereafter by defferentiated myoepithelial cells keeps the polarity of this primary duct tree.

Secondary duct tree development occurs in females in response to circulating ovarian The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in females are homologous to testes in males, in that they are both gonads and endocrine glands hormones from puberty Puberty refers to the process of physical changes by which a child's body becomes an adult body capable of reproduction. Puberty is initiated by hormone signals from the brain to the gonads . In response, the gonads produce a variety of hormones that stimulate the growth, function, or transformation of brain, bones, muscle, skin, breasts, and. Estrogen Estrogens are a group of steroid compounds, named for their importance in the estrous cycle, and functioning as the primary female sex hormone, their name comes from estrus (period of fertility for female mammals) + gen = to generate promotes branching differentiation[7], whereas in males testosterone Testosterone is a steroid hormone from the androgen group. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands. It is the principal male sex hormone and an anabolic steroid inhibits it. A mature duct tree reaching the limit of the fat pad of the mammary gland comes into being by bifurcation of duct terminal end buds(TEB), secondary branches sprouting from primary ducts[8][9] and proper duct lumen formation. These processes are tightly modulated by components of mammary epithelial ECM interacting with systemic hormones and local secreting factors. However, for each mechanism the epithelial cells' "niche" can be delicately unique with different membrane receptor profiles and basement membrane The basement membrane is a sheet of cells and fibers that underlies two other kinds of cells -- the epithelium, which lines the cavities and surfaces of organs, and the endothelium, which lines the interior surface of blood vessels thickness from specific branching area to area, so as to regulate cell growth or differentiation sub-locally[10]. Important players include beta-1 integrin Integrins are receptors that mediate attachment between a cell and the tissues surrounding it, which may be other cells or the extracellular matrix . They also play a role in cell signaling and thereby define cellular shape, mobility, and regulate the cell cycle, epidermal growth factor receptor(EGFR), laminin-1/5, collagen-IV, matrix metalloproteinase(MMPs), heparan sulfate proteoglycans etc. Elevated circualting level of growth hormone and estrogen get to multipotent cap cells on tip of TEB through a leaky thin layer of basement membrance and promote specific gene expression. Hence cap cells can differentiate into myoepithelial and luminal (duct) epithelial cells, and the increased amount of activated MMPs can degrade surrounding ECM helping duct buds to reach further in the fat pads[11][12]. Lumen is formed when branching by inner body cells apoptosis for lack of survival signals. On the other hand, basement membrane The basement membrane is a sheet of cells and fibers that underlies two other kinds of cells -- the epithelium, which lines the cavities and surfaces of organs, and the endothelium, which lines the interior surface of blood vessels along the mature mammary ducts is thicker with strong adhesion to epithelial cells via binding to integrin Integrins are receptors that mediate attachment between a cell and the tissues surrounding it, which may be other cells or the extracellular matrix . They also play a role in cell signaling and thereby define cellular shape, mobility, and regulate the cell cycle and non-integrin receptors. When side branches develop, it is a much more “pushing-forward” working process including extending through myoepithelial cells, degrading basement membrane and then invading into a periductal layer of fibrous stromal tissue[13]. Degraded basement membrane The basement membrane is a sheet of cells and fibers that underlies two other kinds of cells -- the epithelium, which lines the cavities and surfaces of organs, and the endothelium, which lines the interior surface of blood vessels fragments (laminin-5) roles to lead the way of mammary epithelial cells migration.[14]. Whereas, laminin Laminin is a protein found in the extracellular matrix, the sheets of protein that form the substrate of all internal organs also called the basement membrane. It is the major non-collagenous component of the basal lamina, such as those on which cells of an epithelium sit. It has four arms that can bind to four other molecules. The three shorter-1 interacts with non-integrin receptor dystroglycan Dystroglycan is one of the dystrophin-associated glycoproteins, which is encoded by a 5.5 kb transcript in Homo sapiens by chromosome 3. There are two exons that are separated by a large intron. The spliced exons codes for a protein product is finally cleaved into two non-covalently associated subunits, [alpha] and [beta] (C-terminal) negatively regulates this side branching process in case of cancer Cancer is a class of diseases in which a group of cells display uncontrolled growth (division beyond the normal limits), invasion (intrusion on and destruction of adjacent tissues), and sometimes metastasis (spread to other locations in the body via lymph or blood). These three malignant properties of cancers differentiate them from benign tumors,[15]. These complex "Yin-yang In Chinese philosophy, the concept of yin yang is used to describe how seemingly disjunct or opposing forces are interconnected and interdependent in the natural world, giving rise to each other in turn. The concept lies at the heart of many branches of classical Chinese science and philosophy, as well as being a primary guideline of traditional" balancing crosstalks between mammary ECM and epithelial cells "instruct" healthy mammary gland development until adult The term adult has at least three distinct meanings. It can indicate a biologically grown or mature person. It may also mean a plant, animal, or person who has reached full growth or alternatively is capable of reproduction, or the classification legal adult, generally determined as a person who has attained the legally fixed age of majority; as.

True secretory alveoli only develop in pregnancy Pregnancy is the carrying of one or more offspring, known as a fetus or embryo, inside the uterus of a female. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets. Human pregnancy is the most studied of all mammalian pregnancies. Obstetrics is the surgical field that studies and cares for high risk pregnancy, when rising levels of estrogen and progesterone Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. Progesterone belongs to a class of hormones called progestogens, and is the major naturally occurring human progestogen cause further branching, together with an increase in adipose tissue In histology, adipose tissue or body fat or just fat is loose connective tissue composed of adipocytes. Adipose tissue is derived from lipoblasts. Its main role is to store energy in the form of fat, although it also cushions and insulates the body. Obesity or being overweight in humans and most animals does not depend on body weight but on the and a richer blood flow It can be calculated by dividing the vascular resistance into the pressure gradient. In gestation Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time . The time interval of a gestation plus 2 weeks is called gestation period, and the length of time plus 2 weeks that the offspring have spent developing in the uterus is called gestational age, serum progesterone remains at a stably high concentration so signaling through its receptor is continuously activated. As one of the transcribed genes, Wnts secreted from mammary epithelial cells act paracrinely to induce more neighboring cells branching[16][17]. When the lactiferous duct tree is almost ready, "leaves" alveoli are differentiated from luminal epithelial cells and added at the end of each branch. In late pregnancy and for the first few days after giving birth, colostrum Colostrum is a form of milk produced by the mammary glands of mammals in late pregnancy. Most species will generate colostrum within one day of giving birth is secreted . Milk secretion (lactation Lactation describes the secretion of milk from the mammary glands, the process of providing that milk to the young, and the period of time that a mother lactates to feed her young. The process occurs in all female mammals, and in humans it is commonly referred to as breastfeeding or nursing. In most species milk comes out of the mother's nipples;) begins a few days later due to reduction in circulating progesterone Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. Progesterone belongs to a class of hormones called progestogens, and is the major naturally occurring human progestogen and the presence of another important hormone prolactin Prolactin or Luteotropic hormone (LTH) is a peptide hormone primarily associated with lactation. In breastfeeding, the act of an infant suckling the nipple stimulates the production of prolactin, which fills the breast with milk via a process called lactogenesis, in preparation for the next feed. Oxytocin, another hormone, is also released, which, which mediates further alveologenesis and milk protein production. Laminin and collagen in myoepithelial basement membrane interacting with beta-1 integrin Integrins are receptors that mediate attachment between a cell and the tissues surrounding it, which may be other cells or the extracellular matrix . They also play a role in cell signaling and thereby define cellular shape, mobility, and regulate the cell cycle on epithelial surface again, is essential in this process[18][19]. Their binding ensures correct placement of prolactin receptors on basal lateral side of alveoli cells and directional secretion of milk into lactiferous ducts[20][21]. Suckling of the baby causes release of hormone oxytocin Oxytocin is a mammalian hormone that also acts as a neurotransmitter in the brain which stimulates contraction of the myoepithelial cells. In this way of combined control from ECM and systemic hormones, milk secretion can be reciprocally amplified so as to provide enough nutrition for the baby.

After lactation, decreased prolactin level and stop of baby suckling cause mammary involution. All alveoli and secretory duct structure collapse by programmed cell death (apoptosis Apoptosis is the process of programmed cell death (PCD) that may occur in multicellular organisms. Programmed cell death involves a series of biochemical events leading to a characteristic cell morphology and death, in more specific terms, a series of biochemical events that lead to a variety of morphological changes, including blebbing, changes) and autophagy for lack of growth promoting factors either from the ECM or circulating hormones[22][23]. At the same time, apoptosis of blood capillary endothelial cells The endothelium is the thin layer of cells that line the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. Endothelial cells line the entire circulatory system, from the heart to the smallest capillary. These cells reduce turbulence of the flow of blood allowing the speeds up the regression of lactation ductal beds. Shrinkage of the mammary duct tree and ECM remodeling by various proteinase is under the control of somatostatin Somatostatin (also known as growth hormone inhibiting hormone or somatotropin release-inhibiting factor (SRIF)) is a peptide hormone that regulates the endocrine system and affects neurotransmission and cell proliferation via interaction with G-protein-coupled somatostatin receptors and inhibition of the release of numerous secondary hormones and other growth inhibiting hormones and local factors[24]. This big structure change leads loose fat tissue to fill up the empty space thereafter. But a functional lactiferous duct tree can be formed again when a female is pregnant for another time.

Breast cancer

Tumorigenesis Cell division is a physiological process that occurs in almost all tissues and under many circumstances. Under normal circumstances, the balance between proliferation and programmed cell death, usually in the form of apoptosis, is maintained by tightly regulating both processes to ensure the integrity of organs and tissues. Mutations in DNA that in mammary glands can be induced biochemically by abnormal expression level of circulating hormones or local ECM components[25], or from a mechanical change in the tension of mammary stroma[26]. Under either of the two circumstances, mammary epithelial cells would grow out of control and eventually result in cancer Cancer is a class of diseases in which a group of cells display uncontrolled growth (division beyond the normal limits), invasion (intrusion on and destruction of adjacent tissues), and sometimes metastasis (spread to other locations in the body via lymph or blood). These three malignant properties of cancers differentiate them from benign tumors,. Almost all instances of breast cancer originate in the lobules or ducts of the mammary glands.

Other mammals

The number and positioning of complex and simple mammary glands varies widely in different mammals. The nipples and glands can occur anywhere along the two milk lines The milk lines are two parallel lines, formed by thickenings of the epidermis along the ventral surface of mammals of both sexes. They extend from the upper limbs (arms) to the lower limbs (legs) and are developed in the embryo. They give rise to the mammary glands and nipples but are otherwise usually not visible in the adult, two roughly-parallel lines along the ventral Standard anatomical terms of location are employed in sciences which deal with the anatomy of animals to avoid ambiguities which might otherwise arise. They are not language-specific, and thus require no translation. They are universal terms that may be readily understood by zoologists who speak any language aspect of the body. In general most mammals develop mammary glands in pairs along these lines, with a number approximating the number of young typically birthed at a time. The number of nipples varies from 2 (in most primates) to 16 (in pigs). The Virginia Opossum The Virginia Opossum , commonly known as the North American Opossum, is the only marsupial found in North America north of the Rio Grande River. A solitary and nocturnal animal about the size of a domestic cat, it is a successful opportunist and is found throughout Central America and North America east of the Rockies from Costa Rica to southern has 13, one of the few mammals with an odd number[27][28]. The following table lists the number and position of glands normally found in a range of mammals:

Species [29] Anterior (thoracic The thorax is a division of an animal's body that lies between the head and the abdomen) Intermediate (abdominal In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax (chest) and pelvis. The region enclosed by the abdomen is termed the abdominal cavity. In arthropods it is the most distal section of the body which lies behind the thorax or cephalothorax) Posterior (Inguinal) Total
Goat The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep: both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of goats, sheep Domestic sheep are quadrupedal, ruminant mammals typically kept as livestock. Like all ruminants, sheep are members of the order Artiodactyla, the even-toed ungulates. Although the name "sheep" applies to many species, in everyday usage it almost always refers to Ovis aries. Numbering a little over 1 billion, domestic sheep are the most, horse guinea pig 0 0 2 2
Cattle 0 0 4 4
Cat 2 2 2 6
Dog [30] 4 2 2 or 4 8 or 10
Mouse 6 0 4 10
Rat 6 2 4 12
Pig 6 6 4 16
Elephants, primates 2 0 0 2

Male mammals typically have rudimentary mammary glands and nipples, with a few exceptions: male mice don't have nipples, and male horses lack nipples and mammary glands.[citation needed] The male Dyak fruit bat has lactating mammary glands;[31] male lactation occurs infrequently in some species, including humans.

Mammary glands are true protein factories, and several companies have constructed transgenic animals, mainly goats and cows, in order to produce proteins for pharmaceutical use. Complex glycoproteins such as monoclonal antibodies or antithrombin cannot be produced by genetically engineered bacteria, and the production in live mammals is much cheaper than the use of mammalian cell cultures.

Evolution

This section requires expansion.

It is believed that the mammary gland is a transformed sweat gland, more closely related to Apocrine sweat glands[citation needed]. There are many theories of how they evolved, but since they do not fossilize well, supporting such theories presents a major difficulty for the researcher. One theory proposes that mammary glands evolved from glands that were used to keep the eggs of early mammals moist.[1]

Gallery

Cattle

Cat

Pig

Sheep

Goat

Elephant

Mouse

Human

See also

References

  1. ^ Watson, C.J. & Khaled, W.T. Mammary development in the embryo and adult: a journey of morphogenesis and commitment. Development 135, 995-1003 (2008)
  2. ^ Wiseman, B.S. & Werb, Z. Stromal effects on mammary gland development and breast cancer. Science 296, 1046-9 (2002)
  3. ^ Watson, C.J. & Khaled, W.T. Mammary development in the embryo and adult: a journey of morphogenesis and commitment. Development 135, 995-1003 (2008)
  4. ^ Wysolmerski, J.J. et al. Rescue of the parathyroid hormone-related protein knockout mouse demonstrates that parathyroid hormone-related protein is essential for mammary gland development. Development 125, 1285-94 (1998)
  5. ^ Watson, C.J. & Khaled, W.T. Mammary development in the embryo and adult: a journey of morphogenesis and commitment. Development 135, 995-1003 (2008)
  6. ^ Hens, J.R. & Wysolmerski, J.J. Key stages of mammary gland development: molecular mechanisms involved in the formation of the embryonic mammary gland. Breast Cancer Res 7, 220-4 (2005)
  7. ^ Sternlicht, M.D. Key stages in mammary gland development: the cues that regulate ductal branching morphogenesis. Breast Cancer Res 8, 201 (2006)
  8. ^ Wiseman, B.S. & Werb, Z. Stromal effects on mammary gland development and breast cancer. Science 296, 1046-9 (2002)
  9. ^ Sternlicht, M.D., Kouros-Mehr, H., Lu, P. & Werb, Z. Hormonal and local control of mammary branching morphogenesis. Differentiation 74, 365-81 (2006)
  10. ^ Fata, J.E., Werb, Z. & Bissell, M.J. Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes. Breast Cancer Res 6, 1-11 (2004).
  11. ^ Wiseman, B.S. et al. Site-specific inductive and inhibitory activities of MMP-2 and MMP-3 orchestrate mammary gland branching morphogenesis. J Cell Biol 162, 1123-33 (2003)
  12. ^ Koshikawa, N., Giannelli, G., Cirulli, V., Miyazaki, K. & Quaranta, V. Role of cell surface metalloprotease MT1-MMP in epithelial cell migration over laminin-5. J Cell Biol 148, 615-24 (2000)
  13. ^ Wiseman, B.S. & Werb, Z. Stromal effects on mammary gland development and breast cancer. Science 296, 1046-9 (2002)
  14. ^ Dogic, D., Rousselle, P. & Aumailley, M. Cell adhesion to laminin 1 or 5 induces isoform-specific clustering of integrins and other focal adhesion components. J Cell Sci 111 ( Pt 6), 793-802 (1998)
  15. ^ Muschler, J. et al. A role for dystroglycan in epithelial polarization: loss of function in breast tumor cells. Cancer Res 62, 7102-9 (2002)
  16. ^ Robinson, G.W., Hennighausen, L. & Johnson, P.F. Side-branching in the mammary gland: the progesterone-Wnt connection. Genes Dev 14, 889-94 (2000)
  17. ^ Brisken, C. et al. Essential function of Wnt-4 in mammary gland development downstream of progesterone signaling. Genes Dev 14, 650-4 (2000)
  18. ^ Streuli, C.H., Bailey, N. & Bissell, M.J. Control of mammary epithelial differentiation: basement membrane induces tissue-specific gene expression in the absence of cell-cell interaction and morphological polarity. J Cell Biol 115, 1383-95 (1991)
  19. ^ Streuli, C.H. et al. Laminin mediates tissue-specific gene expression in mammary epithelia. J Cell Biol 129, 591-603 (1995)
  20. ^ Streuli, C.H., Bailey, N. & Bissell, M.J. Control of mammary epithelial differentiation: basement membrane induces tissue-specific gene expression in the absence of cell-cell interaction and morphological polarity. J Cell Biol 115, 1383-95 (1991)
  21. ^ Streuli, C.H. et al. Laminin mediates tissue-specific gene expression in mammary epithelia. J Cell Biol 129, 591-603 (1995)
  22. ^ Zarzynska J, Motyl T.Apoptosis and autophagy in involuting bovine mammary gland. J Physiol Pharmacol. 2008 Dec;59 Suppl 9:275-88
  23. ^ Fadok, V.A., Clearance: the last and often forgotten stage of apoptosis. J Mammary Gland Biol Neoplasia, 1999. 4(2): p. 203-11
  24. ^ Motyl, T., et al., Apoptosis and autophagy in mammary gland remodeling and breast cancer chemotherapy. J Physiol Pharmacol, 2006. 57 Suppl 7: p. 17-32
  25. ^ Gudjonsson, T. et al. Normal and tumor-derived myoepithelial cells differ in their ability to interact with luminal breast epithelial cells for polarity and basement membrane deposition. J Cell Sci 115, 39-50 (2002)
  26. ^ Provenzano, P.P. et al. Collagen density promotes mammary tumor initiation and progression. BMC Med 6, 11 (2008)
  27. ^ With the Wild Things - Transcripts
  28. ^ Raising Orphaned Baby Opossums
  29. ^ Merle Cunningham, Animal Science and Industry ISBN 9780130462565
  30. ^ Dog breeds vary in the number of mammary glands: larger breeds tend to have 5 pairs, smaller breeds have 4 pairs.
  31. ^ Francis, Charles M.; Anthony, Edythe L. P.; Brunton, Jennifer A.; Kunz, Thomas H. (1994-02-24). "Lactation in male fruit bats". Nature (Nature Publishing Group) 367: 691–692. doi:10.1038/367691a0. http://www.nature.com/nature/journal/v367/n6465/abs/367691a0.html. Retrieved on 2008-05-14.

External links

Female reproductive system
Adnexa
Follicles/ Folliculogenesis corpus (hemorrhagicum, luteum, albicans) · Theca of follicle (externa, interna) · Follicular antrum (Follicular fluid) · Corona radiata · Zona pellucida · Membrana granulosa (Granulosa cells)
Ovaries/ Oogenesis Germinal epithelium · Tunica albuginea · cortex (Cumulus oophorus, Stroma) · Medulla
Fallopian tubes Isthmus · Ampulla · Infundibulum · Fimbria
Ligaments Broad (components: Mesovarium, Mesosalpinx, Mesometrium contents: Round of uterus, Proper of ovary) · Suspensory of ovary · Cardinal
Uterus corpus/body (Cavity of the body, Fundus)

cervix/neck (External orifice, Canal of the cervix, Internal orifice)

layers (Endometrium, Myometrium, Perimetrium) · Uterine horns
Vulva/ mons pubis
Vagina vestibular glands/ducts (Bartholin's glands/Bartholin's ducts, Skene's glands/Skene's ducts) · Fossa of vestibule of vagina · Vaginal fornix · Hymen · Orifice
Labium commissures (Anterior · Posterior) · Frenulum labiorum pudendi · Labia majora · Cleft of venus · Labia minora · Vulval vestibule · interlabial sulci
Clitoris Vestibular bulbs · Clitoral crura · Corpus cavernosa · Clitoral glans (Frenulum, Hood)
Breast Mammary glands · Nipple · Areola · Lactiferous duct · Cooper's ligaments
Vestiges Wolffian (Gartner's duct, Epoophoron, Paroöphoron) · Canal of Nuck
Other G-spot · Urethral sponge · Perineal sponge

Categories: Breast anatomy | Exocrine system | Glands

 

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