Anatomia De Aparato Reproductor

Reproductive System and Organs (Female) |[pic]  [pic]  [pic] | | |[pic]
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| |Female reproductive system (human) Summary |[pic] | |


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Principio del formulario[pic][pic][pic][pic][pic][pic][pic]
Final del formulario
Reproductive System and Organs (Female)
In both male and female embryos, primordial undifferentiated gonads form on the medial wall of the urogenital ridges. Two pair of ducts initially develop in the gonad, the mesonephric duct (Wolffian duct), and the paramesonephric (Mullerian) duct. The [pic]primordial [pic]undifferentiated germ cells then migrate from theyolk sac to the urogenital ridge during the fourth to eighth week of gestation, where they are required for development of the gonads (testes and ovaries). In the absence of a testicular differentiation factor from the Y chromosome, which directs the production of Mullerian inhibiting substance (MIS) by four to six weeks [pic]gestation in males, the germ cells differentiate into primitive oogoniathat begin mitosis at about six weeks. The first meiotic division is initiated at about 15 weeks, signaling the transformation of oogonia to oocytes. This meiotic division is then arrested at the first prophase until [pic]primordial follicles are formed. Medullary structures infiltrate the ovarian cortex and surround the oocytes to invest each one with a single layer of [pic]primordial granulosacells at about 20 weeks of [pic]gestation, thereby beginning the formation of [pic]primordial follicles. At birth, the human ovary is filled with approximately one million [pic]primordial follicles. In females, the Wolffian duct almost completely disappears.
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In the female, the Mullerian duct starts to develop at six weeks of [pic]gestation as invaginations of the mesonephric kidney. Theinvagination forms a tube for each duct. The tubes on the cranial end open into a celomatic cavity (future peritoneal cavity), while the caudal segments fuse (8 weeks of [pic]gestation) into a Y-shaped uterovaginal primordium. From the cranial portion of each tube arises the fallopian tubes. The caudal (fused) portion becomes the uterus and part of the vagina.
At nine weeks of [pic]gestation,external sexual [pic]differentiation begins. In females, the genital tubercle develop into the clitoris, the urogenital folds form the labia minora, and the labioscrotal swellings become the [pic]labia majora.
The perineum is defined as the region of pelvic outlet below pelvic floor. A diamond shaped area, the perineum is separated into two triangles (the anterior urogenital triangle and theposterior anal triangle) by an imaginary line between the two ischeal tuberosities. The vulva rests on the urogenital triangle diaphragm. The vulva contains the mons pubis, the [pic]labia majora, the labia minora, the clitoris, and the vestibule.
The [pic]labia majora are folds of skin with underlying adipose tissue; they are fused anteriorly with the mons pubis and posteriorly with the perineum. Theskin of the [pic]labia majora contains hair follicles and sebaceous and sweat glands. The labia minora merge anteriorly with the prepuce and frenulum of the clitoris and posteriorly with the labia majora and perineum. The labia minora contains sweat and sebaceous glands, but not hair follicles and adipose tissue. The clitoris is the embryologic equivalent of the penis. It consists in two crura (theequivalent of corpora cavernosa in the male). The vestibule lies between labia minora and is bounded anteriorly by the clitoris and posteriorly by perineum. The urethra and vagina open into the vestibule in the midline. The ducts of Skene(parauretral) glands and Bartolino's glands also empty into vestibule.
The vagina is a muscular tube that extends from above the inferior extent of the cervix...