Free Gender Inequalities Essays and Papers - 123HelpMe
CONTOH JUDUL SKRIPSI SASTRA INGGRIS | Bunda …
The United Nations sees gender equality as an important goal, as four of the eight Millennium Development Goals for lowering poverty levels are directly related to women.
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Many structures in the female reproductive system are homologous to the male structures already studied (homologous means similar in structure, position, and origin but not necessarily function). The ovaries are homologous to the testes, labia majora are homologous to the scrotum, the clitoris is homologous to the penis, the bulb of vestibule is homologous to the corpora spongiosum & bulb of penis, the paraurethral glands are homologous to the prostate, and the greater vestibular glands are homologous to the bulbourethral glands.
Females go through puberty as do males, but there is a distinct nutritional component to the onset of puberty in females. Nutrition is more important for puberty in girls than in boys (although puberty is delayed when either is malnourished) since approximately 140,000 calories are required to support 9 months of fetal growth and 3 months of lactation. The onset of puberty correlated with body weight & fat (about 16 kg fat needed for menarche). Young women athletes, who typically have less adipose, often experience menarche around age 16. After menarche, extreme weight loss or rigorous athletic training may lead to absence of menstruation or amenorrhea. In Europe & U.S., better nutritional standards over past 200 years have caused average age of menarche to drop from 17 to 13 years; poorly nourished women (New Guinea, !Kung tribeswomen) may not experience until age 18 and may not conceive until age 25. In females, growth spurt accompanied by a "fat spurt"; 11 kg fat gained in female-specific areas: neck, posterior arm, mammary, abdominal, prepubic, thigh, flank, and calf; some of these deposits completely mask her underlying muscle.
The synthesis of the female gametes, the ova, is called oogenesis. Around the 3rd month (of fetal development, oogonia develop to larger cells known as primary oocytes; each primary oocytes enter prophase of Meiosis I where they halt development until puberty. Each primary oocyte is surrounded by epithelial (follicular) cells known as the primordial follicle; these nourish the oocyte. Around 7 million potential oocytes in fetal ovary at 5 months; this is reduced to 1 million at birth and few hundred thousand at puberty. Each month after menarche, several primordial follicles respond to FSH causing them to become primary follicles. In these primary follicles, the primary oocytes complete the first round of cell division (Meiosis I). This cell divides into to produce a second oocyte and a 1st polar body which contains little more than discarded material. The secondary oocyte contains most cytoplasm and remains in secondary follicle (now several layers of cuboidal and columnar [granulosa] cells). This cell proceeds to metaphase of Meiosis II and then stops. At ovulation, the secondary oocyte, the first polar body, and some supporting cells are discharged and these enter the Fallopian tube.
If fertilization is to occur, the secondary oocyte must encounter sperm within the first 12-24 hours after ovulation. If fertilized, the secondary oocyte completes Meiosis II which produces a second polar body and an ovum (mature egg). The 1st polar body may also divide and all polar bodies then disintegrate in last part of fallopian tube or uterus (unfertilized secondary oocytes) disintegrate in the same area).
Thus there are a number of differences in gametogenesis between males and females: