Reproductive Anatomy

The ovary has no tubules like the testis, but has fluid-filled vesicles called [1], each housing a single egg. When an egg is released, it travels down a duct called the [2] to reach the uterus. The uterus has a thick muscular wall called the [3], covered on the outer surface with a serosa called the [4] and lined internally with a mucosa called the [5]. The lower end of the uterus is a necklike constriction called the [6], which protrudes into the vagina. Vaginal spaces called the anterior, posterior, and lateral [7] surround it. In childhood, the vagina has a simple cuboidal epithelium, but in puberty this changes to [8], which is better adapted to the future stresses of intercourse and childbirth. All the external female genitals are collectively called the [9]. This area is bordered laterally by thick folds called the [10] with pubic hair on their lateral surfaces. Thinner, hairless folds medial to these are called the [11], and the area between these, which receives the vaginal and urinary orifices, is the [12]. At the anterior margin of this area, the skinfolds (11) meet and form a hoodlike [13] over the glans of the [14]. This organ is structured much like a miniature penis except that the urethra does not pass through it and it lacks one of the erectile tissues, the [15].

Beneath the surface of the vulva are accessory glands and erectile tissues. A pair of small [16] glands, homologous to the male bulbourethral glands, open into the lower vagina and provide lubrication during intercourse. A pair of [17] glands, homologous to the male prostate, lie alongside the urethra and secrete into the vestibule. A pair of erectile tissues, the [18], border the vagina like parentheses and become engorged during sexual arousal.

The breast consists of a pendulous body and, near the armpit, a/an [19]. It is suspended from the skin and pectoralis major muscle by fibrous [20]. The nipple is surrounded by a colored zone called the [21] and often exhibits little papillae called the [22], whose secretions keep the rea from drying and cracking, especially in a nursing mother. Behind the nipple are 15 to 20 [23] ducts.

 1._________________________13._________________________

 2._________________________14._________________________

 3._________________________15._________________________

 4._________________________16._________________________

 5._________________________17._________________________

 6._________________________18._________________________

 7._________________________19._________________________

 8._________________________20._________________________

 9._________________________21._________________________

10._________________________22._________________________

11._________________________23._________________________

12._________________________

Puberty and Menopause

In girls, puberty is triggered by rising levels of GnRH, FSH, and LH as it is in boys, but the gonadotropins have different effects. FSH causes the [24] to secrete estrogens, which stimulate development of the reproductive tract and many of the secondary sex characteristics. Development of the breast buds, called [25], is soon followed by [26], the appearance of pubic and axillary hair. Later comes the first menstrual period, or [27], but this depends on a girl's percent [28] and may therefore be delayed until the mid- to late teens in very lean girls, such as some dancers and athletes. For the first year of menstruation, a girl does not produce eggs, so her cycles are described as [29]. In middle age, women undergo climacteric just as men do, but as part of this they also go through cessation of the menses, or [30], which by definition is unique to women. Unlike men, women are no longer fertile after climacteric.

24._________________________28._________________________

25._________________________29._________________________

26._________________________30._________________________

27._________________________

Oogenesis and the Sexual Cycle

Oogenesis begins with diploid cells called [31], some of which differentiate into [32] and begin meiosis by the time of birth. Most of these undergo a degenerative process called [33] during fetal development and in childhood. Meiosis I resumes in adolescence under the influence of the hormone [34]. In contrast to spermatogenesis, the two daughter cells produced in oogenesis are of unequal size–a large [35] and a small [36]. The latter cell serves only to discard extra chromosomes. The former does not go through meiosis II unless it is [37].

Oogenesis occurs in a monthly sexual cycle of parallel changes in the ovaries and uterus. The first 14 days of the average cycle are called the [38] phase because they are dominated by the growth of the follicles, but this in turn is subdivided into a [39] phase (days 1 - 5) and a [40] phase (days 6 - 14). A primary oocytes is enclosed in a [41] follicle, consisting of a single layer of squamous cells around the egg. FSH causes these cells to enlarge, divide, and stratify, producing a [42] follicle. Small pools of fluid begin to appear amid the granulosa cells of this follicle and soon merge to form a single cavity, the [43]. The follicle is now called a [44] follicle. This follicle has a mound of cells, the [45], over the egg; a wall of [46] cells around the rest of the follicle; a fibrous capsule called the [47]; and a clear layer of gel, the [48], around the egg. As the follicles are developing, cells of the endometrium are undergoing rapid mitosis and rebuilding the stratum [49] lost in the previous menstrual period. From the uterine standpoint, this period is therefore known as the [50] phase. Endometrial cells also develop [51] receptors during this time in preparation for events to come. By day 14, one follicle has outpaced the others and become a mature, or [52], follicle up to 2.5 cm in diameter.

On day 14, over the course of 2 or 3 minutes, [53] occurs and releases an egg into the uterine tube. This is partly a consequence of the secretion of [54] by the pituitary. This hormone causes hyperemia in the ovaries, swelling of the mature follicle, and secretion of the enzyme [55], which weakens the ovarian wall over the follicle. A nipplelike [56] forms, oozes follicular fluid for a minute or two, and then ruptures.

Days 15 - 28 of the sexual cycle are the [57] phase. The first 12 days of this, the [58] phase, are dominated by the [59], a yellowish mass that develops from the ruptured follicle. This structure secretes a large amount of progesterone, stimulating the endometrium to produce [60] and [61] and grow still thicker. If pregnancy does not occur, the 59 begins to degenerate in about 10 days. The spiral arteries of the endometrium constrict, reducing blood flow and inducing the [62] phase of the uterine cycle. This results in necrosis of the endometrium and the accumulation of [63], a mixture of blood and dead tissue, in the uterus. The day that this fluid is first discharged vaginally marks day 1 of the next cycle.

31._________________________48._________________________

32._________________________49._________________________

33._________________________50._________________________

34._________________________51._________________________

35._________________________52._________________________

36._________________________53._________________________

37._________________________54._________________________

38._________________________55._________________________

39._________________________56._________________________

40._________________________57._________________________

41._________________________58._________________________

42._________________________59._________________________

43._________________________60._________________________

44._________________________61._________________________

45._________________________62._________________________

46._________________________63._________________________

47._________________________

Female Sexual Response

During the excitement phase of female sexual response, the vaginal walls are moistened by a serous filtrate called [64], the [65] glands secrete a lubricating fluid near the vaginal orifice, the lower end of the vagina constricts to form the [66], and the uterus stands up more vertically and withdraws its cervix from the vagina, a process called the [67] effect. There are few nerve endings in the vagina; most erotic stimulation is centered instead on the [68]. During orgasm, the 66 strongly contracts a few times, the [69] exhibits peristaltic contractions, and the [70] secrete a fluid similar to the male's prostatic secretion. In the [71] phase, the uterus returns to its normal position and, if semen is present, the cervix may dip into it. The postorgasmic [72] period present in the male is usually not present in the female.

64._________________________69._________________________

65._________________________70._________________________

66._________________________71._________________________

67._________________________72._________________________

68._________________________

Pregnancy and Childbirth

Pregnancy, or [73], lasts an average of 270 days from conception, but to make events more predictable, the date of birth is projected to be 284 days (40 weeks) after the first day of the woman's [74]. All the products of conception (fertilization) are collectively called the [75]–that is, the embryo or fetus plus the fetal membranes and placenta. The developing individual is called a/an [76] for most of the first two weeks, an embryo through week [77], and a fetus from then until birth. Early in pregnancy, the placenta secretes [78], a hormone that sustains and stimulates the corpus luteum in the ovary, stimulates the development of a male fetus, and serves as a basis for pregnancy tests. [79] stimulates maternal and fetal tissue growth, development of the mother's mammary ducts, and softening of the pelvic joints. [80] acts with 79 to inhibit the release of FSH during pregnancy, and it suppresses uterine contractions and stimulates development of the mammary acini. The most abundant hormone of pregnancy is [81]. It seems to act somewhat like growth hormone, it mobilizes fats for fuel, and it antagonizes the effect of insulin in the mother.

Some authorities think the unpleasant side effect of early pregnancy, [82], is a mechanism to protect the developing embryo from dietary toxins, but in some women it leads to [83], such severe vomiting that it may require hospitalization. Later in pregnancy, the metabolic rate and appetite increase, and while some pregnant women greatly overeat and gain excessive weight, the average healthy weight gain is about [84]. Among the important nutritional supplements a pregnant woman should take, [85] is needed for extra hemoglobin synthesis, [86] helps prevent hemorrhage in the baby during birth, and [87] helps prevent neurological disorders of the fetus such as spina bifida. By full term, the growing uterus may reach nearly to the [88] of the sternum. The pressure this produces on the diaphragm may cause breathing difficulty, or [89], until the last month when the fetus drops lower in the pelvic cavity. Increased melanocyte activity in the skin commonly causes darkening of the areolae, a temporary dark line called the [90] on the abdomen, and in some women, temporary blotchy darkening of the face, called [91].

Some women go prematurely to the hospital with "false labor," or [92] contractions. The increasing contractility of the uterus in late gestation may result from the rising level of [93] from the ovaries. Close to term, the posterior pituitary secretes [94] and the uterus develops receptors for it. In true labor contractions, this hormone stimulates strong peristaltic waves in the uterine muscle. According to the [95] theory of labor, this pushes the baby's head against the cervix, stimulating stretch receptors, and transmitting signals to the central nervous system which result in even more secretion of 94. That hormone also indirectly stimulates uterine contractions by triggering the release of [96]. In first-stage labor, two major processes occur in addition to labor contractions: [97], or widening of the cervical canal, and [98], or thinning of the cervical tissue. Second-stage labor begins when the baby's head enters the [99] and ends when the baby is completely expelled. Third-stage labor is the expulsion of the [100]. In the [101], the first six weeks postpartum, the uterus shrinks by a process of self-digestion, or [102], producing a vaginal discharge called [103]. [104] promotes uterine shrinkage by inhibiting estrogen secretion and stimulating oxytocin secretion.

73._________________________ 89._________________________

74._________________________ 90._________________________

75._________________________ 91._________________________

76._________________________ 92._________________________

77._________________________ 93._________________________

78._________________________ 94._________________________

79._________________________ 95._________________________

80._________________________ 96._________________________

81._________________________ 97._________________________

82._________________________ 98._________________________

83._________________________ 99._________________________

84._________________________100._________________________

85._________________________101._________________________

86._________________________102._________________________

87._________________________103._________________________

88._________________________104._________________________

Lactation

For the first 2 or 3 days postpartum, the mammary glands do not secrete milk but [105], a thin yellowish fluid with about one-third less [106] than milk. This fluid provides the infant with [107], giving it a degree of passive immunity to infection. Although the hormone [108] is secreted in pregnancy, it has little effect on the mammary glands as long as the placental steroid levels are high. Once the placenta is shed at birth, this hormone begins to stimulate milk synthesis, but it is a different hormone, [109], that causes the milk to flow down the mammary ducts while an infant is suckling. That hormone works by stimulating [110] cells that enmesh each mammary acinus. Cow's milk is a poor substitute for human breast milk, among other reasons because it contains far higher levels of [111] and [112] and is harder to digest. Milk output by a nursing mother eventually becomes as high as [113] per day.

105._________________________110._________________________

106._________________________111._________________________

107._________________________112._________________________

108._________________________113._________________________

109._________________________

Copyright ©1998 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use and Privacy Policy.
McGraw-Hill Higher Education is one of the many fine businesses of The McGraw-Hill Companies.
For further information about this site contact mhhe_webmaster@mcgraw-hill.com.