Table of contents :

• female reproductive apparatus
• internal female genital organs / organa genitalia feminina interna : the various organs in the female that are concerned with reproduction
• adnexa uteri
• epoöphoron / epoophoron / corpus pampiniforme / pampiniform body / parovarium / Rosenmüller's organ : a vestigial structure associated with the ovary, consisting of a more cranial group of mesonephric tubules and a corresponding portion of the mesonephric duct
• ductus longitudinalis epoöphori / longitudinal duct of epoöphoron / duct of epoöphoron / ductus epoöphorontis longitudinalis / Gartner's canal or duct : a closed rudimentary duct lying parallel to the uterine tube into which the transverse ducts of the epoöphoron open; it is a remnant of the part of the mesonephros that participates in formation of the reproductive organs
• paroöphoron : an inconstantly present small group of coiled tubules between the layers of the mesosalpinx, being a remnant of the mesonephric duct
• exocrine ovaria / ovaries (see also endocrine ovaria and diseases of exocrine ovaria): the female gonad, one of the 2 sexual glands in which the ova are formed. It is a flat oval body along the lateral wall of the pelvic cavity (prolapsed in Douglas' cavity in the pluripara), attached to the posterior surface of the broad ligament (mesovarium).
• utero-ovarian ligament / ligamentum ovarii proprium : a musculofibrous cord in the broad ligament, joining the ovary to the upper part of the lateral margin of the uterus just below the attachment of the uterine tube
• germinal epithelium : thickened peritoneal epithelium covering the gonad from earliest development; formerly thought to give rise to the germ cells, hence the name.
• Farre-Waldeyer white line : the boundary of the insertion of the mesovarium at the hilus of the ovary, separating the peritoneal mesothelium from the germinal epithelium
• tunica albuginea ovarii : the layer of dense connective tissue beneath the germinal epithelium of the ovary
• stroma

Cell types :
• fibroblast
• interstitial cells : masses of large epithelioid, lipid-containing cells in the ovarian stroma, believed to have a secretory function, derived from the theca interna of atretic ovarian follicles, and thus, in humans, more numerous during the first year of life when atresia proceeds rapidly. In women, they are either absent or poorly represented, but in some other mammals, especially rabbits, they are more prominent
• Pflüger's ovarian tubes : groups of cells that grow down and are cut off from the thickened surface layer of the ovary; they surround the primordial sex cells, which develop into primary oocytes, each with a follicular layer
• ovarian follicles : the egg and its encasing cells, at any stage of its development. FOXO3A, plays a vital role in activation of follicles : female mice bred to lack the gene had fewer and smaller litters and were infertile after 15 weeks (which is equal to early adulthood for a woman) as the follicles were activated earlier in life than normal and depleted earlier.
• follicular atresia / atresia folliculi : the degeneration and resorption of an ovarian follicle before it reaches maturity and ruptures. Granulosa cells are replaced by fibroblasts, the antral fluid is resorbed and the tissue within the basal lamina is replaced by avascular scar (corpora albicantes)
• oogenesis : the process of formation of female gametes (oocytes) via meiosis
• ooblast : a primordial cell from which an oocyte (ovum) ultimately is developed.
• oogonium : a primordial oocyte during fetal development; it is derived from a primordial germ cell, multiplies rapidly, then becomes encapsulated in primordial follicle cells and, near time of birth, becomes a primary oocyte by entering into prophase of first maturation division.
• oocyte : a developing egg cell in one of 2 stages:
• the primary oocyte (one that has begun but not completed the first maturation division) is derived from an oogonium by differentiation near the time of birth
• the secondary oocyte (one in the period between the first and second maturation division) is derived from a primary oocyte shortly before ovulation by a division that splits off the first polar body. Ovulation follows. If fertilized, the secondary oocyte divides into an ootid and the second polar body; otherwise it perishes.
• polar bodies : the small nonfunctional cells with a haploid chromosome complement, consisting of a small amount of cytoplasm and a nucleus, resulting from unequal division of the primary oocyte (first polar body) and, if fertilization occurs, of the secondary oocyte (second polar body); the polar body appears as a speck at the animal pole of the egg
• ovum / egg : the female reproductive cell which, after fertilization, becomes a zygote that develops into a new member of the same species. The human mature oocyte: a round cell about 0.1 mm in diameter, produced in the ovary, where there is deposited around it a noncellular covering (oolemma; zona pellucida; zona radiata). It consists of protoplasm that contains some yolk, enclosed by a thin cell wall (vitelline membrane : the cytoplasmic, noncellular membrane surrounding the eggs of various animals, especially the membrane enveloping the yolk of telolecithal eggs). There is a large nucleus (germinal vesicle), within which is a nucleolus (germinal spot)
• primitive or primordial ovum : an oocyte very early in its development.
• permanent ovum : an ovum ready for fertilization.
• macrolecithal or megalecithal ovum : one with much yolk.
• medialecithal ovum : one with a medium amount of yolk.
• microlecithal or miolecithal ovum : one containing little yolk.
• alecithal or oligolecithal ovum : one with only a small amount of yolk, or almost no yolk, as in the ova of mammals and many of the invertebrates
• cleidoic ovum : one that possesses within itself sufficient nutritive material for the production of a complete embryo and so needs to absorb nothing from its environment except oxygen, as a bird's egg.
• meroblastic ovum : one that undergoes partial cleavage.
• holoblastic ovum : one that undergoes total cleavage.
• isolecithal ovum : one with yolk evenly distributed throughout the cytoplasm.
• centrolecithal ovum : one in which the yolk is centrally located, and surrounded by a peripheral layer of cytoplasm, as the ova of arthropods.
• telolecithal ovum : one in which the yolk is increasingly concentrated toward one pole.
• ectolecithal ovum : one in which the yolk is situated peripherally.
See also fertilization.
ookinesis : the mitotic movements of the oocyte during maturation and fertilization
In Drosophila mitochondria partition equally on the spindle during germline stem cell and cystocyte divisions. Subsequently, a fraction of cyst mitochondria and Golgi vesicles associates with the fusome, moves through the ring canals, and enters the oocyte in a large mass that resembles the Balbiani's bodies or nuclei / yolk nucleus / vitelline body (a special area of the cytoplasm of an ovum in which the synthetic activities leading to the accumulation of food supplies in the oocyte are apparently initiated) of Xenopus, humans and diverse other species. Balbiani body development requires an intact fusome and microtubule cytoskeleton : initially, the Balbiani body supplies virtually all the mitochondria of the oocyte, including those used to form germ plasm, because the oocyte ring canals specifically block inward mitochondrial transport until the time of nurse cell dumping.
• corona radiata : an investing layer of radially elongated follicular cells surrounding the zona pellucida of a secondary oocyte or ovum.
• zona pellucida / pellucid zone / oolemma : a thick, transparent, noncellular layer or envelope of uniform thickness surrounding an oocyte. Under the light microscope, it appears as a radially striated layer, which can be seen to be microvillous under the electron microscope, and is therefore called zona radiata, zona striata, or striated membrane
• egg envelope or membrane / lemma : any of several investments surrounding the oocyte (ovum or egg): if derived from the oocyte itself, as the vitelline membrane, it is called primary; if from the follicular cells, as the zona pellucida, it is called secondary; if from the oviduct, as the albumen around rabbit's egg or the albumen and shell of hen's egg, it is called tertiary
• shell membrane : a double fibrous layer lining the shell of the egg of some animals, such as birds.
• follicular stigma / macula folliculi : a spot on the surface of an ovary where the vesicular follicle will rupture and permit passage of the ovum during ovulation
Oogenetic or ovarian cycle : the sequence of physiologic changes in the ovary, including
• development and rupture of the follicle : negative estrogen feedback (also inhibin for FSH)
• genetic-driven stages : basal lamina, zona pellucida
• gonadotropin-driven stages : FSH-R (up-regulated by estradiol / E₂) and ER on granulosa cells induces up-regulation of aromatase / CYP19 expression (hence promoting conversion of testosterone and androstenedione - produced by internal theca cells stimulated via LH / hCG-R - into 17b-stradiol / E₂ : positive feedback for FSH-R expression), and then LH / hCG-R (accompanied to down-regulation of FSH-R). Selection of the dominant follicle is achieve since menstrual day 7.
• atretic follicle : an ovarian follicle which has involuted.
• corpora atretica : ovarian follicles that never mature, but undergo degeneration.
• folliculi oophori or ovarici primarii / primary ovarian follicles : immature ovarian follicles, each comprising an immature ovum and the specialized epithelial cells (follicle cells) that surround it
• folliculi ovarici vesiculosi [Graafi] / secondary, antral or vesicular ovarian follicles / graafian follicles or vesicles / ovisac : maturing ovarian follicles among whose cells fluid has begun to accumulate, leading to the formation of a single cavity or antrum and leaving the ovum eccentrically located in a hillock of follicle cells, the cumulus oophorus
• liquor folliculi / follicular fluid : an albuminous fluid in the vesicular ovarian follicle surrounding the ovum.
• cumulus oophorus or ovaricus / ovarian cumulus / discus oophorus, ovigerus, or proligerus : a solid mass of follicular cells surrounding the ovum in the side of a developing vesicular ovarian follicle
• antrum :
• stratum granulosum folliculi ovarici vesiculosi / stratum granulosum ovarii / granular layer of follicle of ovary : the layer of follicle cells lining the theca of a vesicular ovarian follicle.
• theca folliculi / theca of follicle : an envelope of condensed connective tissue surrounding a vesicular ovarian follicle
• tunica interna thecae folliculi / internal coat of theca folliculi / theca interna and internal coat of capsule of graafian follicle : the inner, vascular layer of secretory cells of the theca folliculi
• tunica externa thecae folliculi / external coat of theca folliculi : the outer, fibrous layer of the theca folliculi
• glassy membrane of Slavianski : the basement membrane of a vesicular ovarian follicle which in cross-section appears as a distinct brilliant line and which persists in the ovary long after its follicle has degenerated
• discharge of the ovum : [estradiol]_plasma > 150 pg/mL for > 24-36 hrs => positive estrogen feedback => ovulatory LH surge (> FSH surge) =>

=> ovulation after 10-12 hrs via decreased elasticity of follicular wall and enzyme digestion, and PGE₂, PGF_2a, plasminogen and hyaluronidase
=> corpus luteum formation
• corpus luteum / yellow body of ovary : a yellow glandular mass in the ovary formed by an ovarian follicle that has matured and discharged its ovum; if the ovum has been impregnated, the corpus luteum increases in size and persists for several months (true corpus luteum / corpus luteum of pregnancy / corpus luteum graviditatis). The corpus luteum secretes progesterone

Cell types :
• mulberry cell : a round cell with centrally placed nuclei and coarse cytoplasmic vacuoles near the outer border, developing at the periphery of a retrogressing corpus luteum
• primitive or primordial granulosa cells / prefollicle cells : cells encapsulating the germ cells in the fetal ovary
• granulosa cells : cells surrounding the vesicular ovarian follicle and forming the stratum granulosum and cumulus oophorus; after ovulation they are transformed into ...
• luteal or lutein cells : the plump, pale-staining, polyhedral cells of the corpus luteum; they include
• paraluteal, paralutein, theca-lutein or theca cells : lutein cells derived from the theca interna
• granulosa-lutein cells / corpus luteus cell
=> luteolysis : if impregnation has not taken place within 9-10 days, the corpus luteum degenerates and shrinks (false corpus luteum / corpus luteum of menstruation / corpus luteum menstruationis)
• corpus albicans or fibrosum : white fibrous tissue that replaces the regressing corpus luteum in the human ovary in the latter half of pregnancy, or soon after ovulation when pregnancy does not supervene
• corpora lutea atretica : corpora lutea in which regressive changes have occurred.
See also ovarian germline stem cells (GSCs).
Other cell types :
• hilus cells : groups of large epithelioid cells closely associated with vascular spaces and unmyelinated nerve fibers in the hilus of the ovary and the adjacent mesovarium.
• sympathicotrophic cells : large epithelioid cells occurring in groups and connected with bundles of nonmyelinated nerve fibers in the hilus of the ovary.
• rete ovarii : a homologue of the rete testis, developed in the early female fetus, but vestigial in the adult.
premenopause : 1-2 years before menopause (ranging from a few months to 8-10 yrs); the fertile period of a female according to others. Decreased number of remaining ovarian follicles => decreased inhibin incretion => increased [FSH]_plasma expecially during follicular phase, normal [LH]_plasma => anticipation of dominant follicle recruitment, earlier preovulatory estradiol and LH surges, and ovulation (hyperpolymenorrhea = menorrhage) (vicious circle) with luteal insufficiency (low [progesterone]_plasma) => anovulatory cycles and oligomenorrhea => hypoprogesteronism and relative hyperestrogenism => hypoestrogenism
menopause : cessation of menstruation in the human female, occurring usually between age 46 and 53 (genetically determined anticipations before age 40 and delays up to age 56). This a physiological phenomenon which can be interpretated teleologically as when life expectancy at birth was lower than nowadays, the female could not take care of her new children.
perimenopause : the time just before and after menopause; there are noticeable drops in estrogen levels for 3-5 years prior to menopause.
postmenopause : the time after menopause and before senility. Lack of negative feedback => still pulsatile, progressively increased [GnRH] => [FSH and LH]_plasma (3-13-fold higher within 2-3 years) => progressive decrease since 10-15 yrs after menopause, below premenopausal levels after 20-30 years. Rarely privation metrorrhages. Decreased [androstenedione, dehydroepiandrosterone and DHEA-S]_plasma due to ovarian and adrenal failures with normal [testosterone]_plasma. Increased [E₁ and E₂]_plasma due to extraglandular (fatty tissue, liver and kidney) aromatization of adrenal androstenedione.
Symptoms & signs (climacterium / climacteric : the syndrome of endocrine, somatic, and psychic changes occurring at the time of menopause in the female. Similar changes occurring in men owing to normal diminution of sexual drives with the aging process) :
• early climacterium
• vasomotor disturbances : increased NE/DA ratio in hypothalamic neurons => peripheral vasodilatation => hot flushes (> 66% in first yr, 80% for > 1yr, 25-85% for > 5 yr, sometimes for > 10 yrs) from chest to face lasting 1-2', profuse sweating, tachycardia and PVCs
• psychic disorders (30-40%) : anxiety, irritability, emotional liability, headache, insomnia, fatigability, apathy,
• sexual disorders : dyspareunia, decreased libido
• late climacterium
• type I or postmenopausal osteoporosis :
• cardiovascular disorders : systemic arterial hypertension, proatherogenic lipoprotein profile, prothrombotic, hyperhomocysteinemia
• genitourinary disorders : urogenital and vulvovaginal atrophy (infectious vaginitis, cervical entropion, postcoital bleeding, burning and pruritus), genital prolapse
• skin disorders : teleangiectasia, accentuation of expression lines, decreased function of sweating and sebaceous glands, hirsutism on chin and alopecia, rarefaction of hairs on pubis, fragile nails
Therapy : anti-menopausal drugs
• fallopian tubes / oviducts / salpinges / tuba uterina / uterine tube (see also diseases of fallopian tubes)

Coats :
• perisalpinx : the peritoneal cover of the upper border of the uterine tube
• tunica adventitia tubae uterinae / tela subserosa tubae uterinae : the subserous layer of the uterine tube
• tunica muscularis tubae uterinae / myosalpinx : the muscular coat of the uterine tube.
• subserosal or longitudinal external coat
• submucous or circular internal coat
• tunica mucosa tubae uterinae / mucous coat of uterine tube / endosalpinx : the mucous membrane lining the uterine tube, arranged in longitudinal rugae or folds, and continuous with the mucous lining of the uterus
Cell types : monolayered cylindric epithelium
• ciliated cell (number increased by estrogens, decreased by progesterone)
• secretory cell
Anatomy : it extends from the upper lateral cornu of the uterus to the region of the ovary of the same side; it is attached to the broad ligament by the mesosalpinx, and consists of
• ostium abdominale tubae uterinae / abdominal orifice of uterine tube : the funnel-shaped opening by which the uterine tube communicates with the pelvic cavity.
• fimbriae tubae uterinae / fimbriae of uterine tube : the numerous divergent fringelike processes on the distal part of the infundibulum of the uterine tube.
• fimbria ovarica / ovarian fimbria / fimbriated extremity of fallopian tube : the longest of the processes that make up the fimbriae tubae uterinae, extending along the free border of the mesosalpinx; it is fused to the ovary, so that the ostium of the tube relates to the ovary
• morsus diaboli : the fimbriae at the ovarian extremity of an oviduct
• infundibulum tubae uterinae / infundibulum of uterine tube : the funnel-like dilation at the distal end of the uterine tube, 1-2 cm in length
• ampulla tubae uterinae / ampulla of uterine tube : the thin-walled, almost muscle-free, midregion of the uterine tube, 6-7 cm in length; its mucosa is greatly plicated.
• plicae tubales tubae uterinae / plicae tubariae tubae uterinae / tubal folds of uterine tube : the folds of the mucous lining of the uterine tube, which are high and complex in the ampulla
• isthmus tubae uterinae / isthmus of uterine tube : the narrow part of the uterine tube at its junction with the uterus, 2-3 cm in length
• uterinum tubae uterinae / uterine orifice of uterine tube : the point at which the cavity of the uterine tube becomes continuous with that of the uterus.
• pars uterina tubae uterinae / uterine part of uterine tube : the proximal part of the uterine tube, located within the wall of the uterus.
12-18 cm in length, lumenal diameter varies from 8-15 mm in ampullar extremity to 0.5-1 mm in uterine inserteion. Wall thickness is 1-3 mm
• womb / uterus / metra (see also diseases of uterus) : the hollow muscular organ in female mammals in which the fertilized ovum normally becomes embedded and in which the developing embryo and fetus is nourished.

Organogenesis : natural selection was responsible for changes in both HoxA-11 and HoxA-13 genes in the common ancestor of today's marsupial and placental mammals, and for additional changes to HoxA-11 in the lineage that gave rise to placentals. This timing of the changes to the Hox genes parallels stages in the evolution of the mammalian female reproductive tract, as a primitive uterus and placenta first appeared in the common ancestor of marsupial and placental mammals and then became more elaborate in placental mammals.
In the nongravid human, it is a pear-shaped structure, about 3 inches (6-9 cm : 3 cm in newborn; 33-37 cm at the end of pregnancy) in length, 3-5 cm in width, 2-3 cm in thickness, weighing 30-80 g (1 kg at the end of pregnancy), consisting of ...
• perimetrium / tunica serosa uteri : the serous coat of the uterus
• parametrium : the extension of the subserous coat of the supracervical portion of the uterus laterally between the layers of the broad ligament of uterus
• paracervix : the inferior part of the parametrium.
• broad ligament of uterus
• mesometrium
• round ligament of uterus
• lateral cervical or cardinal ligament
• Mackenrodt's ligament / plica recto-uterina [Douglasi] / rectouterine fold
• uteropelvic ligaments
• Jarjavay's or Petit's uterosacral ligament
• round ligament of uterus
• fundus uteri / fundus of uterus : the part of the uterus above the orifices of the uterine tubes.
• Ruysch's muscle : the muscular tissue of the fundus uteri
• corpus uteri / body of uterus : that part of the uterus above the isthmus and below the orifices of the uterine tubes. In the newborn the cervix is longer than the corpus, but at puberty the corpus rapidly develops

Coats :
myometrium / tunica muscularis uteri / mesometrium : the smooth muscle coat of the uterus, which forms the mass of the organ and consists of smooth muscle cells (10% : hypetrophy and hyperplasia in pregnancy) and fibroblasts (90%)
• no submucosal coat exists
• endometrium / tunica mucosa uteri : the inner mucous membrane of the uterus, the thickness and structure of which vary with the phase of the menstrual cycle. It is functionally divisible into
• stratum basale / basal layer : the deepest layer of the endometrium, which contains the blind ends of the uterine glands; the cells of this layer undergo minimal change during the sexual cycle.
• stratum functionale / functional layer / pars functionalis : the stratum compactum and stratum spongiosum considered together (i.e., all of the endometrium except for the stratum basale), the cells of which are cast off at menstruation and at parturition. It is known as the decidua during pregnancy
• stratum spongiosum / spongy layer : the middle layer of the endometrium, which contains the tortuous portions of the uterine gland
• stratum compactum / compact layer : the layer of the endometrium nearest the surface, which contains the necks of the uterine glands
Cell types : simple cubic / columnar endometrial epithelium (carbohydrate-secreting) with a cytogenous, edematous stroma
• ciliated cell
• glandulae uterinae / uterine glands : simple tubular glands throughout the entire thickness and extent of the endometrium, which become enlarged during the premenstrual period
Menstrual cycle : the type of sexual cycle seen in female humans and some other primates, with physiologic changes in the endometrium that recur at 28 +/- 4 days (longest after puberty and before menopause due to increased frequency of anovulatory cycles) intervals during the reproductive years

• menstrual or desquamative stage / menstruation : the cyclic, physiologic discharge through the vagina of blood and mucosal tissues from the nonpregnant uterus; it is under hormonal control and normally recurs, usually at approximately 4-week intervals, in the absence of pregnancy during the reproductive period (puberty through menopause) of the female of the human and a few species of primates. Lysosomal rupture => PGF_2a => vasoconstriction and uterine contractions; tissue necrosis activates fibrinolysis and stimulates PGI₂ synthesis => partial shedding of the endometrium and 20-80 mL bleeding per vagina, lasting for 4 +/-2 days (decreasing after age 35). Even vaginal epithelium desquamates.
• menstrual decidua / decidua menstrualis : the hyperemic mucosa of the uterus that is shed during the menstrual period.
• rest or regenerative stage : the stage of the uterine mucosa immediately following the completion of menstruation, when only the hormone-unresponsive basal endometrium (0.5 mm in thickness remains)
• proliferative stage : the phase of the uterine mucosa following the first stage of rest: estrogens induces hypertrophy of the glands and increase of the lining epithelium. This phase has constant duration (14 days)
• premenstrual stage : the condition of the uterine mucosa after ovulation and the formation of a corpus luteum.
• progestational or secretory stage (beginning 48 hrs after ovulation up to day 18) : immediately preceding menstruation or implantation of the ovum. This stage has variable duration : progesterone incretion by corpus luteum induces formation of subnuclear vacuoles in > 50% of glandular cells. Estradiol surge induce fluidification of cervical mucus at day 12-13, 24-36 hrs before ovulation, lasting for 24-36 hrs, and tocolysis or uterine cervic (the ostium externi reaches 23 mm in diameter).
• isthmus uteri / isthmus of uterus : the constricted part of the uterus between the cervix and the body.
• cervix contains the uterine cervical canal
• endocervix

Cell types :
• simple columnar endometrial epithelium with longitudinal cryptae
• cervical glands of uterus / glandulae cervicales uteri : mucus-secreting glands located in clefts in the wall of the uterine cervix. (pseudoglandular formation : they are just cryptae or tunnels arising from the plicae of the cervical mucosae)
• squamocolumnar junction
• ectocervix / portio vaginalis cervicis is the part bulging into vagina, described as "tench face" at colposcopy in nulliparous females.

Cell types :
• non-keratinized stratified squamous epithelium with glycogen granules, smooth surface
• ostium uteri / ostium of uterus / orificium externum uteri / external orifice of uterus : the external opening of the cervix of the uterus into the vagina
Its cavity opens into the vagina below, and into the uterine tube on either side at the cornu. It is supported by direct attachment to the vagina and by indirect attachment to various other nearby pelvic structures. It is normally placed in
• antiversion :
• antiflexion :
... modified by position of woman and distention of bladder and rectum.
• uterine segment : either of the portions into which the uterus becomes differentiated early in labor
• upper uterine segment : contractile portion (corpus uteri) that becomes thicker as labor advances
• lower uterine segment : noncontractile portion, thin-walled and passive in character.
Vascularization : 80% of blood comes from the 2 uterine arteries : 8 arciform arteries stem from each uterine artery surrounding the uterine surface and forming anastomoses with the contralateral arteries. From arciform arteries, radial arteries stem, which finally give rise to 200 spiral arteries
• gravid uterus : the pregnant uterus.
• vagina (see also diseases of vagina) : the genital canal in the female, extending from the vulva to the cervix uteri, which receives the penis in copulation
• columnae rugarum vaginae / vaginal columns : well-marked longitudinal ridges on wall of the vagina
• columna rugarum anterior vaginae / anterior vaginal column : a well-marked longitudinal ridge on the anterior wall of the vagina
• columna rugarum posterior vaginae / posterior vaginal column : a well-marked longitudinal ridge on the posterior wall of the vagina
• fornix vaginae / fundus vaginae / fundus of vagina : the recess formed between the vaginal wall and the vaginal part of the cervix; sometimes subdivided into anterior (pars anterior fornicis vaginae), posterior (pars posterior fornicis vaginae), and lateral (pars lateralis fornicis vaginae) fornices, depending on the relation of the recess to the wall of the vagina
Coats :
• tunica mucosa vaginae : the mucous coat of the vagina.
• tunica spongiosa vaginae : a thin layer of spongiose erectile tissue located between the muscular and mucous coats of the vagina, which contains a large plexus of blood vessels.
• tunica muscularis vaginae : the muscular coat of the vagina.
• paracolpium : the connective and other tissues that surround the vagina
Cell types :
• surface cell in squamous epithelium
• basal stem cell of squamous epithelium
The vaginal flora of a healthy woman is composed of the Doderlein bacilli (different species of lactobacilli, mainly Lactobacillus acidophilus) forming a biofilm on the mucosa. These bacteria have a beneficial effect by inhibiting growth, adhesion or spread of other microorganisms. Different mechanisms are recognized, including
• secretion of organic acids (pH 4.5 thanks fermentation of estrogen-induced glycogen storages)
• production of antimicrobial substances (hydrogen peroxide, bacteriocins and biosurfactants)
• competition for nutrients (arginine deiminase)
• competition for receptors (adhesion on the epithelium)
• steric exclusion (biosurfactants, adhesion on the epithelium or on the fibronectin)
• co-aggregation
This ecological balance can be disturbed by drugs (antibiotics and spermicides) or by local devices. A new therapeutic approach has been proposed to restore a normal flora: the use of probiotics by the association of different lactobacilli with combined antimicrobial activity.
Vascularization : cervico-vaginal artery from uterine artery
• ductus paraurethrales urethrae femininae / paraurethral ducts of female urethra / Guérin's glands / Schüller's ducts or glands / Skene's ducts, glands, or tubules / paraurethral glands of female urethra : inconstantly present ducts in the female, which drain a group of the urethral glands into the vestibule; considered by some analogous to prostate, secreting a fluid responsible for female ejaculation
• ductus deferens vestigialis : the vestigial remnants of the mesonephric duct in the female.
• organa genitalia feminina externa / female external genital organs / muliebria : the external genitalia of the female
• urethra feminina
• habenula urethralis : either of 2 whitish lines extending from the urinary meatus to the clitoris in girls and young women.
• clitoris / coles femininus : a small, elongated, erectile body, situated at the anterior angle of the rima pudendi; homologous with the penis in male
• fascia clitoridis / fascia of clitoris : the dense fibrous tissue that encloses the two corpora cavernosa of the clitoris.
• preputium clitoridis / prepuce of clitoris : a fold formed by the union of the labia minora anterior over the clitoris and united with the glans clitoris
• glans clitoridis / glans of clitoris : erectile tissue at the end of the clitoris, which is continuous with the intermediate part of the vestibular bulbs
• frenulum clitoridis / crus glandis clitoridis : the tissue fold on the under surface of the clitoris formed by union of the two medial parts of the labia minora
• corpus clitoridis / corpus of clitoris : the main part of the clitoris, formed by the 2 fused corpora cavernosa, which are embedded anteriorly in the floor of the vestibule of the vagina.
• corpus cavernosum clitoridis / cavernous body of clitoris : a column of erectile tissue on either side (right and left), 4 cm in length the 2 fusing to form the body of the clitoris. The portion free of preputium is just 6 mm in length
• septum corporum cavernosorum clitoridis / septum of corpora cavernosa of clitoris : an incomplete fibrous septum between the 2 lateral halves of the clitoris
• crus clitoridis / crus of clitoris : the continuation of each corpus cavernosum clitoridis, diverging posteriorly to be attached to the ischiopubic rami.
• pudendum femininum / female pudendum / pudendum muliebre : that portion of the female genitalia comprising the
• mons pubis / mons veneris : the rounded fleshy (fatty) prominence over the symphysis pubis.
• vestibulum vaginae / vestibule of vagina : the space between the labia minora into which the urethra and vagina open.
• bulbus vestibuli vaginae / bulb of vestibule of vagina : a body consisting of paired elongated masses of erectile tissue, one on either side of the vaginal opening, united anteriorly by a narrow median band, which then expands slightly to form the glans clitoridis (equivalent to bulb of penis
• commissura bulborum vestibuli / commissure of bulbs of vestibule / pars intermedia bulborum vestibuli : a narrow median band spanning the vaginal orifice to unite the bulbs of the vestibule
• vaginal orifice / orificium or ostium vaginae : the external opening of the vagina, situated just posterior to the external urethral orifice
• hymen : the membranous fold which partially or wholly occludes the external orifice of the vagina.
• imperforate hymen : one which completely closes the vaginal orifice.
• hymen bifenestratus / hymen biforis : a hymen with two openings side by side and a broad septum between them
• annular or circular hymen : a hymen with a circular opening.
• cribriform or fenestrated hymen : a hymen pierced by many small perforations.
• denticular hymen : a hymen with an opening which has serrate edges.
• falciform hymen : a sickle-shaped hymen.
• lunar hymen : a moon-shaped hymen.
• septate hymen / hymen septus : a hymen in which the opening is divided by a narrow septum.
• hymen subseptus : a hymen in which the opening is partially filled by a septum growing out of one wall, but not reaching the other.
• carunculae hymenales or myrtiformes / hymenal caruncles : small elevations of the mucous membrane encircling the vaginal orifice, being relics of the torn hymen after delivery
• labia minora pudendi / lesser lip of pudendum : a small fold of skin located on either side, between the labium majus and the opening of the vagina.
• labia majora pudendi / greater lip of pudendum : an elongated fold running downward and backward from the mons pubis in the female, one on either side of the median pudendal cleft
• commissura labiorum pudendi
• commissura labiorum anterior / anterior commissure of labia : the junction of the two labia majora anteriorly, at the lower border of the pubic symphysis.
• commissura labiorum posterior / posterior commissure of labia : the apparent junction of the labia majora posteriorly, formed by the forward projection of the tendinous center of the perineum into the pudendal cleft
• fourchette / frenulum of labia majora / frenulum labiorum pudendi / frenum of labia / frenulum of pudendal labia : the posterior union of the labia minora, anterior to the posterior commissure
• lesser vestibular glands / glandulae vestibulares minores : small mucous glands opening upon the vestibular mucous membrane between the urethral and the vaginal orifice.
• greater vestibular gland / Bartholin's gland / glandula vestibularis major / vulvovaginal gland : either of 2 small reddish yellow bodies in the vestibular bulbs, one on each side of the vaginal orifice; they are homologues of the bulbourethral glands in the male

Cell types : Bartholin's gland cell secretes a vaginal lubricating fluid
Commonly used to denote the entire external female genitalia (i.e., to include the clitoris and urethra as well)
• mammary gland / lactiferous gland / glandula mammaria (see also diseases of mammary gland) : the specialized accessory apocrine gland of the skin of female mammals that secretes milk. In the human female, it is a compound tubuloalveolar gland composed of 15 to 25 lobes arranged radially about the nipple and separated by connective and adipose tissue, each lobe having its own excretory (lactiferous) duct / ductus lactiferi / galactophorous or lactiferous tubules / mammary ducts opening on the nipple / papilla mammae / papilla mammaria / mammary papilla / mammilla / teat / thelium (the pigmented projection on the anterior surface of the mammary gland, surrounded by the areola). The lobes are subdivided into lobules, with the alveolar ducts and alveoli being the secretory portion of the gland.
• corpus mammae : the essential mass of the mammary gland, exclusive of the glandular elements, which is thickest beneath the nipple and thinner toward the periphery
• lacteal sinuses / sinus lactiferi / lactiferous sinuses : enlargements in the lactiferous ducts just before they open onto the mammary papilla
• glands of Montgomery : named after William Fetherstone H. Montgomery, they are a group of 12-15 sebaceous glands in the areola of the nipple that produce small prominences around the nipple of the breast that enlarge during pregnancy and lactation, having the appearance of small seedlike tubercles. They were previously described by Giovanni Battista Morgagni of Morganella morgagni fame.
Embryogenesis : mammary or milk line / mammary ridge : a ridge of thickened epithelium from axilla to groin in the mammalian embryo along which nipples and mammary glands develop, all but one usually disappearing in the human
Cell types :
• mammary gland cell (milk-secreting)
• myoepithelial cell
• breast stem cells
Effect of autacoids :
• stimulators of cellular differentiation : IGF-1, IGF-2, EGF, TGF-a
• inhibitors of cellular differentiation : TGF-b
Effects of hormones :
• estradiol induces enlargement, division, and enlenghtnment of tubular ducts and maturation of nipples
• progesterone induces development of alveola placed at the end of the ducts
Once development is completed, estradiol and progesterone are no longer needed for lactation. human placental lactogen (hPL) / human chorionic somatomammotropin (hCS)1 secreted by placenta at the end of pregnancy prepares breasts for lactation, while prolactin (PRL) induces synthesis of b-casein and other milk proteins.
Thelarche : the beginning of development of the breasts at puberty, occurring in the age range 8-13 years.
• mammoplasia / mastoplasia : the development of breast tissue
• adolescent mammoplasia : the development of breast tissue at adolescence, applied especially to the development and later regression which occurs in males during puberty.
Lactation : the secretion of milk, or the period of the secretion of milk
In rabbits 2-methylbut-2-enal (2MB2) in milk acts as a pheromone triggering coordinated motions of the head and suckling in neonatal rabbits
• colostrum
• mature milk : 450-1200 mL / day for the first 4-5 months after birth
• fats : 38 g
• lactose : 70 g
• proteins : 12 g
Milk can be safely stored for up to 24 hours at 60°F. Even when a mother's own supply of nutrients and energy is limited, she still is able to produce breast milk of sufficient quantity and quality to support the growth and health of her infant. Increasing the intake of fluid does not seem to affect milk volume.
Even when concentrations in human milk are markedly lower than in bovine milk or formula, nutrients from human milk might have much greater bioavailability for the infant because of specific biologic factors, such as the infant's receptor-mediated uptake of iron from human milk. A significantly higher score on the Wechsler Intelligence Scales for Children-Revised (WISC-R) was found in children at 7.5-8.0 years of age fed expressed human milk than in those fed formula in early infancy. Similar findings have been reported for full-term infants.
• let-down reflex / milk ejection reflex / milk let-down reflex : the ejection or release of milk from the alveoli of the breast into the ducts, caused by a combination of neurogenic and hormonal reflexes involving the hormone oxytocin and, to a lesser extent, vasopressin
• weaning : discontinuation of the breast feeding of an infant, with substitution of other feeding habits, around month 6.
Web resorces :
• Biology of the mammary gland
• Breastfeeding at CDC
• Human Milk Banking Association of North America (HMBANA)
• pregnancy / cyophoria
• encyesis : normal uterine pregnancy
• human chorionic gonadotropin (hCG)
• human placental lactogen (hPL) / human chorionic somatomammotropin (hCS) increases since pregnancy week 12 to 36, fluctuating in the last month. It regulates fat and carbohydrate metabolism (the main energy sources for fetus) by decreasing insulin sensitivity in the pregnant, and increases nitrogen retention by shifting amino acids to the fetus
• progesterone secreted partly by corpus luteum and partly by maternal adrenals
• 17-OH-progesterone secreted by corpus luteum (stimulated by human chorionic gonadotropin (hCG) produced by syncytiotrophoblast since day 8 after ovulation = day 1 after blastocyst nidation) during the first 6 weeks of pregnacy (peak at pregnancy week 10-12) and then secreted by the syncytiotrophoblast up to end of pregnancy (when plasma concentration = 150 ng/mL). On the contrary of other species, in humans the beginning of labor is not related to progesterone concentrations. Pregnandiol is cleared by fecal and renal routes. It induces myometrial atony and inhibits T-lymphocyte responses : administration of progesterone synthesis inhibitors of anti-progesterone antibodies induces abortion.
• 17b-estradiol / E₂ is secreted by corpus luteum in the first 7-8 weeks, then by syncytiotrophoblast. Up to pregnancy wk 20 estrone and 17b-estradiol are higher than estriol, then from pregnancy wk 20 to 30 all 3 estrogens have the same plasma concentrations, and finally after pregnancy wk 30 estriol has the highest concentration thanks to intense androgen synthesis by fetal adrenals and liver (16a-dehydroxylation of DHEA-S)
• estriol is not essential for pregnancy (sulfatase deficiency only causes delayed onset of labor and sometimes postnatal ichtyosis in male newborns since month 2-3 of extrauterine life). Urinary clearance is reduced by anencephalia (lack of ACTH), therapeutic administration of corticosteroids to pregnant (negative feedback), adrenal cortical hypoplasia, lack of placental sulfatase (Y-linked trait), reduced placental tissue (gestosis, delayed delivery), maternal liver diseases imparing conjugation, impaired enterohepatic circulation, severe renal diseases
Across the animal kingdom, birth rate falls steadily with increasing food requirements. Energy use is closely linked to size, so bigger animals have fewer offspring. This seemed not to hold for humans. A female gorilla weighs in at about 100 kg, and can expect to have between 3 and 6 offspring. The average North American woman weighs considerably less, but will have < 2 babies. But human birth rates fit the pattern perfectly if you look at total energy consumption. Considering food, transport, heating, entertainment and so on, the average North American runs at 11,000 W : this puts them in the King Kong range. North Americans' energy consumption is equivalent to the metabolism of a 30,000-kilogram primate. And they have a birth rate to match. In darwinian terms, it doesn't make sense that greater resources aren't used to make babies. The high cost of living - and competing - in developed societies might be the answer. The cultural drive to supply children with an expected level of wealth seems more important than the drive to produce offspring : whatever is driving humans to voluntarily limit reproduction must be a very powerful force.
Mothers who think they have longer to live are more likely to give birth to boys than girls a society where there is no obvious lack of resources : every extra year on the clock increased the odds of producing a male by 1%. The finding backs up a 30-year-old hypothesis^ref that suggests women can bias the sex of their unborn babies, to enhance the chances of their genes being passed on to future generations. Boys need more looking after than girls, the theory says. So when food is scarce and resources are low, females preferentially give birth to girls because they are more likely to live through the hard times : rural Ethiopian women with low levels of nutrition are more likely to give birth to girls^ref. Male babies are more likely to spontaneously abort than female babies, so women may need to be on top form to carry a son to term. Once born, males may also require more parental investment than females. Women tend to breast-feed sons longer than daughters. But boys are able to produce more offspring, so when resources are plentiful, mothers should be more likely to give birth to boys, to maximise the number of potential grandchildren. Perceived life expectancy may be the observable product of an evolved, subconscious psychological mechanism that assesses environmental and physical conditions.
• Hofbauer cells
• placentation : the process of placenta formation and the result, especially with respect to taxonomically relevant aspects of structure
• placenta : a fetomaternal organ characteristic of true mammals during pregnancy, joining mother and offspring, providing endocrine secretion and selective exchange of soluble, bloodborne substances through an apposition of uterine and trophoblastic vascularized parts (hemochorial placenta : fetal capillary endothelium + stromal villus connective tissue + chorial epithelium of villus)
• fetal placenta / placenta foetalis / pars fetalis placentae
• maternal or uterine placenta / placenta uterina / pars uterina placentae : the maternally contributed part of the placenta, derived from the decidua basalis
• decidua / membranae deciduae / caduca, decidual or deciduous membrane / tunica decidua : the modified endometrium of the pregnant uterus induced by maternal progesterone. All decidua, except the deepest layer, is shed at parturition (secundation)
• decidual cells : cells of the uterine endometrium that become modified and specialized during pregnancy. They can be also seen in pseudodecidual reactions of endometrial stroma during hyperlutealism (e.g. in luteal body persistence, extrauterine pregnancy or exogenous progesterone administration)
• decidua parietalis or vera / parietal or true decidua : the portion of the decidua lining the uterus elsewhere than at the site of attachment of the chorionic vesicle
• decidua basalis or serotina / basal decidua / membrana serotina : the portion of the decidua directly underlying the chorionic vesicle and attached to the myometrium
• decidua capsularis or reflexa / capsular or reflex decidua : the portion of the decidua directly overlying the chorionic vesicle and facing the uterine cavity
• decidua subchorialis : the maternal component of the tissue comprising the closing ring of Winkler-Waldeyer.
• placenta-derived multipotent cells
According to species :
• the area of vascular apposition may be
• placenta diffusa : a placenta in which placental tissue is distributed over the chorionic membrane, as in swine
• cotyledonary
• zonary or zonular placenta : a belt-shaped placenta, as occurs in carnivores.
• discoid placenta / placenta discoidea : a disk-shaped placenta.
• the nature of apposition
• labyrinthine placenta : one in which maternal blood courses in channeled trophoblasts.
• villous placenta : one characterized by the presence of villi which are outgrowths of the chorion.
• the intimacy of apposition may vary according to what layers are lost of those originally interposed between maternal and fetal blood (maternal endothelium, uterine connective tissue, uterine epithelium, chorion, extraembryonic mesoderm, and endothelium of villous capillary)
The chorion may be joined by and receive blood vessels from either the yolk sac or the allantois, and the uterine lining may be
• deciduate or deciduous placenta : a placenta or type of placentation in which the decidua or maternal parts of the placenta separate from the uterus and are cast off together with the fetal (or more precisely, trophoblastic) parts.
• nondeciduate or nondeciduous placenta : one in which the maternal component remains in the uterus instead of being cast off together with the trophoblastic derivatives.
The human placenta is discoid, villous, hemochorial, chorioallantoic, and deciduate. After birth, it weighs about 500-600 g (1/6 of fetal weight) and is about 16-20 cm in diameter and 2-4 cm thick at center and 0.5 cm thick in periphery, discounting the decidua basalis and the maternal blood in the intervillous space (a principal functional part into which the chorionic villi dip and which leaks out at birth). The villi are grouped into adjoining cotyledons making about 20 velvety bumps on the side of the placenta facing the uterus; the side facing the fetus is smooth and covered with amnion, a thin avascular layer that continues past the edges of the placenta to line the entire hollow sphere of chorion except where it is reflected to cover the umbilical cord. The umbilical cord joins fetus and placenta and usually joins the placenta near the center, although it sometimes inserts at the edge, on the nonplacental chorion, or on an accessory placenta.
• implantation / nidation : attachment of the blastocyst to the epithelial lining of the uterus, its penetration through the epithelium, and, in humans, its embedding in the compact layer of the endometrium, beginning 6-7 days after fertilization of the ovum and completing within 13 days. It mostr commonly occurs in the posterior wall of the uterine body in the midleine, half a way between the lower
• trophoblast selectin L-mediated adhesion at the maternal-fetal interface
• eccentric implantation : embedding of the blastocyst within a recess of the uterine cavity.
• interstitial implantation : complete embedding of a blastocyst within the endometrium, as in humans
• central, circumferential or superficial implantation : embedding of the blastocyst so that the blastocyst, and later the chorionic sac, come to occupy the uterine cavity
• teratic implantation : the partial blending of an imperfect with a nearly perfect fetus.

Every successful pregnancy requires proper embryo implantation. Low implantation rate is a major problem during infertility treatments using assisted reproductive technologies (ART). Targeted deletion of EDG7 / LPA₃ in mice resulted in significantly reduced litter size, which could be attributed to delayed implantation and altered embryo spacing. These 2 events led to delayed embryonic development, hypertrophic placentas shared by multiple embryos and embryonic death. An enzyme demonstrated to influence implantation, COX2, was downregulated in LPA₃-deficient uteri during pre-implantation. Downregulation of COX2 led to reduced levels of PGE₂ and PGI₂, which are critical for implantation. Exogenous administration of PGE₂ or carbaprostacyclin (a stable analogue of PGI₂) into LPA₃-deficient female mice rescued delayed implantation but did not rescue defects in embryo spacing. These data identify LPA₃ receptor-mediated signalling as having an influence on implantation, and further indicate linkage between LPA signalling and prostaglandin biosynthesis^ref.
• closing plug / Schlusskoagulum : the clot that closes the gap made in the uterine lining by the implanting blastocyst
Extragenital organ modifications in pregnancy :
• body weight :

ref	weight increase [g]
	wk 10	wk 20	wk 30	wk 40
fetus	5	30	1500	3400
placenta	20	170	430	650
amniotic fluid	30	350	750	800
uterus	140	320	600	970
mammary gland	45	180	360	405
blood	100	600	1300	1250
interstitial fluids	0	30	80	1680
total	340	1950	5020	9155
effective body weight increase	650	4000	8500	12500
difference (maternal reserve)	310	2050	3480	3345

• hematological parameters in pregnants

	average female aged 18-35	pregnant female aged 18-35 (at pregnancy wk 28-40)
plasma volume	2,500-2,700	3,500-4,200
RBCs	4.0-4.6	3.6-4.2
HGB	11.3-16.5	10.1-13.8 (physiological pregnancy anemia)
HCT	36-44	29-37
MCV	81-90	84-94
WBC	4.0-8.0	5.0-15.0 (expecially neutrophils)
PLT	150-350	120-280
proteins	7 g/dL	- 1g/dL (relative decrease) in the first 16-20 weeks (expecially albumin, not CRP), then stable : relative increased in g-globulin fraction increases the ESR
prothrombin activity (PA)	78-100	78-100
fibrinogen	217-437	412-600 (also increased fibrinogen degradation products and ESR)
AT-III	90-110	80-100
Fe	27-187	35-131
Tf	200-500	364-636
ferritin	16-80	2-20
alkaline phosphatase	x	1.5-2x
uric acid	2.75-5.25	2.5-4.3
azotemia	22.8-38.6	13.7-24.5
creatininemia	0.7-0.9	0.5-0.7
CLcreatinine	88-128	120-160
AFP		increases up to pregnancy wk 32, then decreases unless NTD exist

• cardiac output increases by 30% (from 4.5-5 L/min to 6-6.5 L/min)
• mild reduction in systolic blood pressure (< 135-140 mmHg) and moderate reduction in diastolic blood pressure (< 90 mmHg) => increased differential arterial blood pressure
• increased tidal volume => minute volume = 10-11 L at end of pregnancy
• increased plasma renal flow, GFR and FF => glycosuria and increased CL_creatinine => decreased creatininemia, uremia and uricemia
• hyperorexia with preferences for some foods; sensation of abundant salivation and dysphagia; gastroesophageal reflux (decreased gastric secretion, tone and motility), constipation, hypercholesterolemia, and cholelithiasis
• reproductive immunology
• Homo sapiens developmental physiology section
• embryogenesis
• pregnancy-associated diseases
Genital phenomena :
• breasts : accentuation of subcutaneous venous network, hyperpigmentation of secondary areola and Montgomery tubercles (hypertrophic sebaceous glands); colostrum secretion since first weeks of pregnancy up to day 3-4 after delivery
• vagina : imbibition, cyanosis and leukorrhea
• uterus : lenght > 30 cm, wifth > 25 cm, depth > 20 cm => cavity volume increases by 1000-folds (expecially in fundus uteri) and weight increases from 50-60 g up to 1,000-1,500 g due to water retention, myometrial hypertrophy and hyperplasia due to estrogens and progesterone and (after pregnancy wk 10-12) also to increased endolumenal pressure. A rotation along the longitudinal axis places the left border anteriorly and the right border posteriorly. A mucous plug formed by secretions of the mucous glands of the cervix uteri closes the cervical canal during pregnancy. The cervix uteri, consisting mainly of fibrous connective tissue, supports mechanically the conceptus
• uterine sinuses : venous channels in the wall of the uterus in pregnancy
Fetal placement :
• situation : relationship between the longitudinal (longest) axes of fetus and uterus
• presentation : that portion of the fetus that is touched by the examining finger through the cervix or, during labor, is bounded by the girdle of resistance
• presenting part : 1. that portion of the fetus that is touched by the examining finger through the uterine cervix and, during labor, is bounded by the girdle of resistance.  2. that portion of the body of the fetus that is farthest forward in the birth canal or is closest to it.
• fetal attitude : head is flexed over trunk, forearm are flexed over arms and crossed in front of sternum, thighs are flexed over abdomen, and legs are flexed over thighs and crossed in front of the ventral plane, forming an ovoid. Variations in attitude are less frequent during last weeks of pregnancy
• position : situation of the fetus in the pelvis, determined and described by the relation of a given arbitrary point (point of direction / fetal or presentation index) in the presenting part to a given arbitrary point in the coronal plane of the maternal pelvis (maternal index)
• cephalic presentation
• vertex presentation (point of direction : lambdoid, occipital, posterior, smaller or triangular fontanelle; commonly occiput) (95%)
• left occipitoanterior (LOA) (left ileo-pectineal eminence) (60%)
• left occipitoposterior (LOP) (left sacroiliac symphisis) (3%)
• left occipitotransverse (LOT)
• right occipitoanterior (ROA) (right ileo-pectinal eminence) (6%)
• right occipitoposterior (ROP) (right sacral symphisis) (30%)
• right occipitotransverse (ROT)
• bregma presentation (point of direction : bregmatic, frontal or larger fontanelle)
• face presentation (point of direction : chin) (0.5%)
• left mentoanterior (LMA)
• left mentoposterior (LMP)
• left mentotransverse (LMT)
• right mentoanterior (RMA)
• right mentoposterior (RMP)
• right mentotransverse (RMT)
• brow presentation (point of direction : nose root)
• left frontoanterior (LFA)
• left frontoposterior (LFP)
• left frontotransverse (LFT)
• right frontoanterior (RFA)
• right frontoposterior (RFP)
• right frontotransverse (RFT)
• pelvic presentation (breech) (4%)
• complete breech presentation (25-30%, expecially in multiparae) : feet crossed and thighs flexed on abdomen; buttocks and feet against the outlet (point of direction : sacrum)
• left sacroanterior (LSA)
• left sacroposterior (LSP)
• left sacrotransverse (LST)
• right sacroanterior (RSA)
• right sacroposterior (RSP)
• right sacrotransverse (RST)
• incomplete breech presentation (30-35%) : same designations as above
• buttocks variety (70%)
• incomplete variety with procidentia : one or more little parts (footling, knees) precede the buttocks
• shoulder presentation (point of direction : acromion) (< 0.5%)
• left scapuloanterior (LScA)
• left scapuloposterior (LScP)
• right scapuloanterior (RScA)
• right scapuloposterior (RScP)

Level of presented part : distance between te index point of the presented part and the plan of the ischiatic protuberances
• - : above the plan
• + : below the plan
• 0 : same level
• pelvic diameters
• fetal diameters :
• biparietal diameter (BPD) : 9.2 cm
• suboccipital bregmantic diameter : 9.5 cm
• small circumference = 30-32 cm
• occipital-frontal diameter : 11-11.5 cm
• middle circumference = 34 cm
• supraoccipital-mentonier diameter = 13.5-14 cm
• maximal circumference = 37 cm
• submental-bregmatic diameter = 9.5 cm
• bisacromial diameter = 11-12 cm
• bistrochanteric diameter = 11-12 cm
• synclitism / syncliticism : parallelism between the planes of the fetal head and those of the pelvis.
• asynclitism : lateral deflection of the fetal head in labor so that the sagittal suture is deflected anteriorly toward the symphysis or posteriorly toward the sacrum
• anterior asynclitism / Nägele's obliquity : the position of the fetal head in which the anterior parietal bone presents to the parturient canal, the biparietal diameter being oblique in relation to the brim of the pelvis
• posterior asynclitism / Litzmann's obliquity : inclination of the fetal head so that the posterior parietal bone presents to the parturient canal

• lightening : the sensation of decreased abdominal distention produced by the descent of the uterus into the pelvic cavity, usually occurring 2-3 weeks before labor begins.
• engagement : the entrance of the fetal head, or presenting part, into the superior pelvic strait and beginning descent through the pelvic canal so that its biparietal plane is below the plane of the pelvic inlet.
• labor / childbirth / delivery / parturition : the function of the female organism by which the product of conception is expelled or extracted from the uterus through the vagina to the outside world. Labor may be divided into 4 stages:
• prelabor stage : since engagement of the presented part
• prodromal stage : since onset of rhythmic and coordinate uterine contractions sensed as painful by the pregnant, lastinf on average 8 hrs in nullipara and 5 hrs in the multipara. Lumbosacral pain, pollakyuria and vesical tenesmus.
• the first (the stage of cervical dilatation) begins with the onset of regular uterine contractions and ends when the os is completely dilated (10 cm), lasting on average 4-5 hrs in nullipara and 2 hrs in multipara, ending with dilatation of the os uteri
• the second stage (stage of expulsion / expulsive stage) extends from the end of the first stage until the expulsion of the infant from the uterus and vagina is completed, lasting on average 1 hr in the nullipara and 20-30' in multipara
• the third stage (placental or secundation stage) extends from the expulsion of the child until the placenta and membranes (afterbirth / secundina / secundinae / secundines) are expelled from the uterus (spontaneously or artificially), lasting 20'-1 hr
• placental detachment : retraction isn't folowed by placental retraction as the latter lacks elastic tissue => detachment and hemorrhage
• central detachment (70%) => retroplacental hematoma => Schultze mechanism : expulsion of the placenta with the smooth, glistening, fetal surface appearing at the vulva
• peripheral detachment (30%) => metrorrhage => Duncan mechanism : expulsion of the placenta with the maternal, or rough, surface appearing at the vulva.
Progressive slow descent of umbilical cord out of external genitalia. The fundus uteri is at the level of the navel.
• transit of placenta in vagina and detachment of amniochorial membranes
• expulsion of placenta thanks to voluntary maternal contractions after stimulation of vagina. The fundus uteri is in the intermediate third between the navel and the pubis
Mechanical muscular hemostasis (15-20') => physiological thrombosis
• the fourth or post-partum stage denotes the hour or 2 after delivery, when uterine tone is established. Surveillance of pulse, temperature, pressure, bleedings, uterine contraction and retraction is recommended
• labor pains : the rhythmic pains of increasing severity and frequency, caused by contractions of the uterus during childbirth
• spontaneous labor : labor in which no artificial aid is required => spontaneous delivery : birth of an infant without any mechanical, pharmacologic, or medical assistance.
• vaginal delivery : delivery of an infant through the normal openings of the uterus and vagina.
• complete birth : the complete separation of the infant from the maternal body (after cutting of the umbilical cord).
Phenomenology of delivery :
• maternal or dynamic phenomena
• expansion of lower uterine segment in the last 8-10 weeks of pregnancy
• dilatation of internal ostium => flattening of uterine cervix => dilatation of external ostium (Friedman's cervimetric curves plot diameter vs. time)
• incuneation of the fetal head in the lower uterine segment, the amnion is separated in a posterior bag (which is influenced by endouterine pressure) and an anterior bag (poorly influenced by endouterine pressure, preserving its integrity until labor; when incuneations is not perfect => premature rupture of membranes (PROM); on the other had rupture may occur after beginning of expulsive efforts and may lead to untempestive placental detachment)
• distention of vagina, perineum and vulva => laceration of hymen in the nullipara
• maternofetal or mechanic phenomena
• reduction and engagement of the presented part
• progression when the cervical canal is completely dilated (if earlier cervical laceration and hemorrhage may occur)
• internal rotation in the intermediate strictus of pelvis
• disengagement of the presented part (in vertex presentation, when occiput contacts the pubic symphysis)
• internal rotation of shoulders => external rotation or restitution of head
• total expulsion of fetus : after the head the right (or anterior) shoulder and then the left (or posterior) shoulder
• fetal or plastic phenomena
• caput succedaneum
• cephalohematoma
An uncomplicated delivery is associated with loss of 500 ml of blood.
• number of fetuses
• simple birth : the birth of a single offspring
• multiple or plurimous birth : the birth of 2 or more offspring produced in the same gestation period, the frequency of birth of viable offspring after such multiple pregnancy having been computed as follows: Hellin-Zeleny law : 1 in about 89 pregnancies ends in the birth of twins; 1 in 89 x 89, or 7921, of triplets; 1 in 89 x 89 x 89, or 704,969, of quadruplets.
• polytocous : giving birth to several offspring at one time.
• septuplet : one of seven offspring produced in one gestation period.
• number of pregnancies
• secundigravida : a woman pregnant for the second time; also written gravida II
• secundiparity : the condition of being a secundipara : a woman who has had 2 pregnancies which resulted in viable offspring; also written para II
• septigravida : a woman pregnant for the seventh time; also written gravida VII
• septipara : a woman who has had seven pregnancies which resulted in viable offspring; also written para VII or VII-para
Symptoms & signs : pregnancy signs
• presumption (extragenital) signs :
• sympathetic phenomena : nausea gravidarum and vomiting of pregnancy at morning, sensation of abundant salivation, pyrosis, and gastralgia, constipation, changes in appetite and taste since pregnancy week 5-6, attenuating since week 12 and disappearing after week 16; varices in lower limbs or vulva/perineum, pollakiuria, effort dyspnea, sciatalgia, cramps, paresthesias at extremities
• increased volume of abdomen due to meteorism (allowed by pregnant's intestinal hypomotility) or uterus hypertrophy after pregnancy wk 14-16


• encyopyelitis : dilatation of the ureters and/or renal pelvis during normal pregnancy with associated edema, but seldom with all the classical signs of inflammation
• cutaneous hyperchromia : melasma / chloasma / mask of pregnancy, striae gravidarum, linea nigra (a name given the tendinous mesial line of the abdomen (linea alba) when it has become pigmented in pregnancy)
• probability (genital) signs :
• amenorrhea (hemorrhages during nidation or abortion may mimick menstruations in 6-7% of all pregnancies)
• breast tenderness and volume increase after pregnancy wk 10, colostrum, hyperpigmentation of areolae, Montgomery's tubercles, secondary areola)
• uterus : raises in abdomen since pregnancy wk 10-12, up to xyphoid process at pregnancy wk 38, then lowered by 2-3 cm due to initial engagement of presented fetal part => supine hypotension syndrome and hydronephrosis
• vagina and vulva : cyanosis, hyperemia, leukorrhea
• Chadwick's sign : a dark bluish or purplish-red and congested appearance of the vaginal mucosa
• Gauss' sign : an increase in uterine mobility
• Goodell's sign : softening of the cervix uteri
• Hegar's sign : softening of the lower segment of the uterus
• ballottement : a palpatory maneuver to test for a floating object. The term is applied especially to a maneuver for detecting the existence of pregnancy by pushing up the head or breech of a fetus by fingers inserted into the vagina, so as to cause the fetus to rise and fall again like a heavy body in water
• abdominal or indirect ballottement : that which is effected by the finger applied to the abdominal wall : the head rebounds but the breech does not
• Hegar's sign : softening of the lower segment of the uterus
• Piskacek's sign :  asymmetrical enlargement of the corpus uteri due to enlargement of the pregnant uterus in the cornual region, usually over the site of implantation.
• Béclard's sign : a sign of the maturity of the fetus consisting of a center of ossification in the lower epiphysis of the femur.
• Leopold's maneuvers : 4 maneuvers in palpating the abdomen for ascertaining the position and presentation of the fetus.
• 1st maneuver : both hands are placed with the ulnar border over the abdomen and the upper uterine border is defined by measuring its distance from the upper border of pubic symphisis
• 2nd maneuver (determines situation) : hands are placed on both sides of abdomen and they can be made nearer only in longitudinal situation
• 3rd maneuver (determines engagement of presented part) : the presented part is kept between thumb and index and middle finger. It is mobile only when it is not engaged yet
• 4th maneuver (determines presented part and confirms engagement) : the fingertips of both hands are slipped craniocaudally through the border of the pelvic inlet
• McDonald maneuver : measurement of the contour of the abdomen to calculate the duration of pregnancy
• vaginal exploration in gynaecological position : the free hand pushes the uterus and adnexa toward the exploring fingers. Asepsis is required only if membranes are ruptured, so that the once-preferred rectal exploration is discouraged. Until pregnancy wk 12-14, it detects increased uterine volume, since pregnancy wk 6-7 it detects softening of the portio vaginalis (first sign of Hegar); uterine contractions may be global or (expecially in the first trimester) partial, causing sensation of rugosity (second sign of Hegar). Active and passive dilatation of the cervical canal and shortening of the cervix uteri allows contact with the presented part in the days preceeding the labor
• certainty signs :
• positive radioimmunological tests
• echography : visualization of gestational bag or parts of embryo or fetus
• perception of active fetal movements since pregnancy wk 18-20
• detection of embryonic or fetal heartbeat instrumentally (since pregnancy wk 8-9 with real-time or doppler echography) or acoustically (since pregnancy wk 20-22 according to abdominal thickness, amniotic fluid volume, wall of nidation, fetal situation and position)
Laboratory examinations : pregnancy tests
• early pregnancy test : a do-it-yourself immunologic test for pregnancy performed in the home as early as 1 day (usually 5 days) after menstruation was expected (missed period); a variety of tests exist, all based on an increase in urinary levels of b-hCG after fertilization
• xenodiagnosis
Although there are marked individual variations and methodological biases and differences among empirical studies, pregnancy appears to be usually accompanied by a decrease in sexual desire, coital frequency, and orgasm. Sexual behavior in pregnancy has been traditionally restricted and is currently poorly defined. Sexual proscriptions may precipitate sexual frustration and marital estrangement. Abortion is only rarely caused by coitus. The relationship of coitus and orgasm to prematurity and distress of the fetus and newborn has not been clearly established. Coitus can indirectly result in maternal, fetal, and neonatal morbidity and mortality through the spread of sexually transmitted diseases. Deaths from air embolism in pregnancy associated with cunnilingus and vaginal insufflation have been reported^ref.
Water births have become popular among mothers and midwives because the buoyancy and warmth of the water promotes natural labour while providing a non-invasive safe and effective form of pain management^ref. In 1992 the House of Commons Select Health Committee's report on maternity services recommended that all hospitals should provide women with the "option of a birthing pool where this is practicable." A subsequent surveillance study of all NHS maternity units between 1994 and 1996 found that 0.6% of all deliveries in England and Wales occurred in water^ref. Practitioners and parents should remember, however, that birthing pools pose potential risks for the baby :
• respiratory distress due to water aspiration after an underwater birth and subsequent pulmonary oedema^ref. Some researchers have suggested that "babies can only drown when submerged, only if they are already severely compromised and literally at their `last gasp,' as water stimulates vagal inspiration receptors causing glottic closure."^ref In lambs, however, inhibitory mechanisms that prevent breathing until the lamb is in contact with cold air can be overridden by sustained hypoxia^ref. Likewise, in a birthing pool, some babies with unrecognised hypoxia may gasp underwater. Indeed, the 1994 to 1996 survey cited 2 reports of water aspiration^ref, and similar cases have been documented in the literature^{ref1, ref2}. Although such events seem uncommon, this may be the result of under-reporting. Respiratory distress immediately after birth is common and has various aetiologies. Thus, unless a careful history is taken, the cause the respiratory distress may be misdiagnosed^ref. Support for causality due to aspiration of water is the fact that the infant developed symptoms soon after birth, with resolution by 48 hours. In addition, there were no risk factors for infection or indeed any bacterial infection identified. Infection after water birth has been described^{ref1, ref2, ref3}. When the baby is delivered after spontaneous labour at term, transient tachypnoea of the newborn is unlikely; indeed, the chest radiograph is consistent not with that diagnosis but with aspiration.
• water intoxication
• hyponatraemia
• hypoxic ischaemic encephalopathy
• cord rupture with neonatal haemorrhage
• pneumonia^{ref1, ref2}
A systemic review of randomised trials has shown that immersion during labour is associated with significant reductions in the use of epidural, spinal, or paracervical analgesia and in women's reports of pain, but highlighted there were insufficient data to determine the outcome from randomised trials of birth in water for women or their infants^ref. Women who have water births are usually considered to be "low risk," and so they and their infants should have an excellent prognosis. Practitioners and parents need to be aware of these potential risks so that mothers can make a fully informed decision about place of delivery^ref.
Web resources : Comparative Placentation for > 140 mammal species from Kurt Benirschke
• puerperium : the period from the end of the third stage of labor until involution of the uterus is complete, usually lasting 3 to 6 weeks. Cyclic ovarian activity begins within 6-8 weeks. In women who don't lactate menstruation appear within 40-50 days (caput partum), while in lactating females amenorrhea lasts on average 67 days. At puerperium day 10-12 the uterine fundus is no longer palpable (the weight reduces by 50% in the first week) over the pubic symphysis and volume comes back normal at week 6. In the first days the puerpera may have lumbosacral pain duet to uterine contractions, expecially during lactation. Exudates causes uterine discharges termed loci (lociation), with a blood component disappearing at day 6-7, while discharge disappears at week 5-6
Web resources : The Female Reproductive System
• male reproductive apparatus
• internal male genital organs / organa genitalia masculina interna : the various organs in the male that are concerned with reproduction
• seminal vesicles / vesicula seminalis / glandula seminalis / seminal gland / glandula vesiculosa (see also diseases of seminal vesicles) : either of the paired, sacculated pouches attached to the posterior part of the urinary bladder; the duct of each joins the ipsilateral ductus deferens to form the ejaculatory duct
• ductus excretorius glandulae vesiculosae / excretory duct of seminal gland / ductus excretorius glandulae seminalis / ductus excretorius vesiculae seminalis : the duct that drains the seminal vesicle and unites with the ductus deferens to form the ejaculatory duct
Coats :
• tunica muscularis glandulae vesiculosae / tunica muscularis glandulae seminalis / tunica muscularis vesiculae seminalis : the muscular coat of the seminal gland (seminal vesicle)
• tunica mucosa glandulae vesiculosae / tunica mucosa glandulae seminalis / tunica mucosa vesiculae seminalis : the mucous coat of the seminal gland (seminal vesicle)
• tunica adventitia glandulae vesiculosae / tunica adventitia glandulae seminalis / tunica adventitia vesiculae seminalis : the adventitious coat of a seminal gland (seminal vesicle)
Cell types :
• seminal vesicle cell (seminal fluid components-secreting, Frc included)
• seminal vesicle duct cell
Lallemand-Trousseau bodies / Bence Jones cylinders : cylindrical gelatinous bodies forming the contents of the seminal vesicles
• prostate (gland) / prostata / glandula prostatica (see also diseases of prostate)

The prostate is made up partly of 30-50 compound tubuloalveolar glands, and partly of muscular fibers that encircle the urethra and contract before ejaculation
• ductus or ductuli prostatici / ducts or ductules of prostate gland / prostatic ducts : minute ducts from the prostate gland that open on either side into or near the prostatic sinuses on the posterior wall of the urethra
Cell types :
• prostatic gland acinar epithelial cells (seminal fluid components-secreting)
• prostasomes are membranous vesicles exocyted by acinar cells into the prostate lumen, and they contain large amounts of cholesterol, sphingomyelin, calcium, cathelicidin antimicrobial peptide (CAMP), and several enzymes. Prostasomes are involved in a number of biological functions. At ejaculation, these prostasomes are expelled with prostate secretions and are to be found in the seminal plasma as seminal prostasomes, which facilitate sperm viability and vitality in various ways
• corpora amylacea
• prostatic gland duct cylindric cells
• in periurethral ducts urothelium replaces cylindric cells
• basal cubic cells are stem cells expressing high-molecular weight cytokeratins
• neuroendocrine cells
Anatomy : surrounds the neck of the bladder and the urethra. The so-named "capsule" is a fibrous area without cleavage plans : it lacks at the basis and at the apex, while it is more developed anteriorly. The prostate is often artificially subdivided into lobes :
• median lobe
• Albarrún's gland : that part of the median lobe of the prostate underneath the uvula vesicae.
• Albarrún's tubules : small branching tubules in the cervical part of the prostate gland
• 2 lateral lobes
... but actually only MacNeal zones can be distinguished :
• transitional zone (TZ) (5%) around proximal prostatic urethra
• central zone (CZ) (25%) at both sides of urethra, from the basis to the seminal colliculus
• peripheral zone (PZ) (75%) is the remaining zone

Oblique coronary section along ejaculatory ducts :

Sagitall section :

Oblique coronary section along premontanal urethra :

The rectovesical septum / septum rectovesicale / Denonvilliers fascia is a membranous partition separating the rectum from the prostate and urinary bladder.
Ducts empty into the prostatic portion of the urethra via prostatic or urethral utricle / utriculus prostaticus (the remains of the lower part of the paramesonephric duct in the male; it is a small blind pouch arising in the prostatic substance and opening onto the seminal colliculus, crest, or hillock / colliculus seminalis / caput gallinaginis / verumontanum (VM), a prominent portion of the urethral crest on which are the opening of the prostatic utricle and, on either side of it, the orifices of the ejaculatory ducts. The prostate contributes to the seminal fluid a secretion containing prostate-specific acid phosphatase (PSAP), citric acid, and proteolytic enzymes (including prostate-specific antigen (PSA)) that account for the liquefaction of the coagulated semen
• prostatic sinus / sinus prostaticus : the posterolateral recess between the seminal colliculus and the wall of the urethra
The volume is estimated by TRUS using a variation of the prolate ellipse formula : V = (longitudinal axis) x (transverse axis) x (anteroposterior axis) x h/6^ref
• Cowper's bulbourethral glands / bulbocavernous gland / anteprostatic gland / glandula bulbourethralis : either of 2 glands embedded in the substance of the sphincter of the male urethra, just posterior to the membranous part of the urethra; they are homologues of the greater vestibular glands in the female
• ductus glandulae bulbourethralis / duct of bulbourethral gland / cowperian duct : a duct passing from the bulbourethral gland through the urogenital diaphragm into the bulb of the penis and entering the spongy part of the urethra
Cell types : bulbourethral gland cell (mucus-secreting)
• Littrè's glands / Morgagni's glands / glandulae urethrales urethrae masculinae / urethral glands of male urethra : mucous glands in the wall of the male urethra

Cell types : Littrè gland cell (mucus-secreting)
• exocrine testes / gemellus (see also endocrine testes) are located within scrotum

Organogenesis : around week 7-8 of fetal life differentiation of genital tract and gonads occurs according to sexual chromosomes. Renal descent at month 2, transabdominal descent (driven by AMH) down to inguinal region at month 3, descent through inguinal canal (driven by DHT) down to scrotum at month 8, posteriorly to peritoneo-vaginal duct.
The dydimus or testicle has a tunica albuginea testis or limitating that thickens into the testicular mediastinum / mediastinum testis, from which septula testis / septa of testis (connective tissue lamellae from the inner surface of the tunica albuginea, which unite to form the mediastinum testis) arise that divide the cavity into lobule, each occupied by 3-4 convoluted seminiferous tubules arising from sex cords, among which mesenchymal androgenic Leydig's interstitial cells are found. Each convoluted tubule is covered externally by connective tissue and myoid cells whose cortex actin undergoes peristaltic movements. Inside the testis, from the wall into the lumen, successive stages of spermatogenesis occur, and germ cells are nourished by supporting Sertoli's cells. Convoluted seminiferous tubules confluite into 1 straight seminiferous tubule per lobule
• descensus testis : the descent of the testis from its fetal position in the abdominal cavity to the scrotum; it normally occurs during the 28th week of fetal life and is essential to spermatogenesis

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Coats :
• tunica albuginea testis : the dense, white, inelastic tissue immediately covering the testis, beneath the visceral layer of the tunica vaginalis testis.
• tunica dartos / dartos muscle : the thin layer of subcutaneous tissue underlying the skin of the scrotum, consisting mainly of nonstriated muscle fibers (musculus dartos, which is sometimes used to refer to the entire tunica dartos)
• tunica propria tubuli testis : the proper coat of the seminiferous tubules
• seminiferous tubules : channels in the testis in which the spermatozoa develop and through which they leave the gland
• column of Sertoli : an elongated Sertoli cell in the parietal layer of the seminiferous tubules.
• tubuli seminiferi contorti / convoluted seminiferous tubules : the numerous delicate, contorted canals within each lobule of the testis; its epithelial lining contains Sertoli's cells and germ cells.
• tubuli seminiferi recti / straight seminiferous tubules : the straight terminal portion of the seminiferous tubules; they join to form the rete testis.
Cell types :
• spermatogenesis : the process of formation of spermatozoa, including spermatocytogenesis and spermiogenesis.
• spermioteleosis : the progressive development of the spermatogonium through the successive changes necessary for becoming a mature spermatozoon.
• spermatocytogenesis : the first stage of formation of spermatozoa in which the spermatogonia develop into spermatocytes and then into spermatids.
• spermatogenic cell / androgone : a cell that produces sperm
• spermatogonium / spermatophore / spermatospore / spermospore / spermatogonial cell : an undifferentiated germ cell of a male, originating in a seminiferous tubule and dividing into 2 primary spermatocytes
• type A or primary spermatogonia : sized 12-19 mm with dark nucleus. They begin to undergo mitoses at the onset of puberty.
• Al
• A-dark
• A-pale
• Ac
• intermediate spermatogonia : sized 10-12 mm with clear nucleus and evident nucleolus
• type B or secondary spermatogonia / primary spermatocyte / spermiocyte : sized 7-8 mm. Due to incomplete cytodieresis these diploid cells are joined into syncitia by intercytoplasmic bridges. They undergo meiosis I :
• zygotene spermatocyte
• preleptotene spermatocyte
... each creating 2 secondary spermatocytes / prespermatids : they in turn undergo meiosis II giving origin to ...
• ... 4 haploid spermatids / spermatoblasts, developing into a spermatozoon
• spermatoblast : a term originally applied to the supporting cells of Sertoli, but now used with the same meaning as spermatid
• spermoplasm : the protoplasm of the spermatids
• acroblast : Golgi material in the spermatid from which arises the acrosome
• acroblastic remnant : the peripheral part of the acroblast which recedes into the protoplasm of the spermatid and later disintegrates
• spermiogenesis / spermiohistogenesis : the second stage in the formation of spermatozoa in which the spermatids transform into spermatozoa. The cycle of seminiferous epithelium constitutes a repetition of stages of cell associations, that all together form the wave of seminiferous epithelium, lasting on average 16 days. Specific cell associations that define the stages of the cycle of the seminiferous epithelium are present within distinct regions that exhibit differential light absorption patterns. In mice there are 12 designated stages and each has a reliable repertoire of germ cells. The germ cells are organized in concentric layers in the tubules beginning with the spermatogonia at the outermost layer, followed by spermatocytes, round spermatids and then the most mature spermatids, the elongating spermatids. The position of the elongating spermatids in relation to the Sertoli cell nucleus (shown in gray) varies throughout the cycle and reflects the organization of these cells as bundles, which are represented by groups of three elongating spermatids in the schematic.