Sistema Reproductor Capítulo 40

Hueso púbico Vejiga urinaria uréter uretra recto pene próstata Vesícula seminal FIGURE 40-11 The human male reproductive tract The male testes hang beneath the abdominal cavity in the scrotum. Sperm pass from the testis to the epididymis, through the vas deferens and urethra to the tip of the penis. Along the way, fluids are added from the seminal vesicles, the bulbourethral glands, and the prostate gland. próstata vaso deferente epidídimo testis glándula bulbouretral Abertura uretral escroto Figure 40-11 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

(a) (b) vaso deferente epidídimo Túbulo testículo espermatogonia seminífero testículo espermatogonia (b) Células hijas spermatozoa FIGURE 40-12 Structures involved in spermatogenesis (a) A section of the testis, showing the seminiferous tubules, epididymis, and vas deferens. (b) Cross section of a seminiferous tubule. The walls of the seminiferous tubules are lined with nurturing Sertoli cells and spermatogonia undergoing meiosis. Mature sperm are freed into the central cavity. Testosterone is produced by interstitial cells. Células de Sertoli capilar Figure 40-12 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

Ocurre continuamente comenzando Espermatogénesis Ocurre continuamente comenzando en la pubertad. espermatogonia FIGURE 40-13 Sperm are produced by meiosis Spermatogonia grow and differentiate to produce spermatocytes, which undergo meiosis and further differentiation to produce haploid sperm. Although 4 chromosomes are shown for simplicity, in humans, the diploid number is 46 and the haploid number is 23. espermatocito primarrio espermatocitos secundarios Esperma- tozoides espermátidas Figure 40-13 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

Espermatozoide cabeza núcleo mitocondrias acrosoma Segmento inermedio flagelo Segmento inermedio mitocondrias núcleo acrosoma FIGURE 40-14 A human sperm cell A mature sperm is a cell equipped with only the essentials: a haploid nucleus, the acrosome (containing enzymes that digest the barriers surrounding the egg), mitochondria for energy production, and a tail (a long flagellum) for locomotion. Figure 40-14 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

Control Hormonal de la Espermatogénesis células Intersticia- les hypotálamo Pituitaria anterior LG FSH LH testículos = inhibits inhibina = stimulates espermatogénesis testosterona Células Sertoli Control Hormonal de la Espermatogénesis FIGURE 40-15 Hormonal control of spermatogenesis GnRH from the hypothalamus stimulates the anterior pituitary to release LH and FSH. LH stimulates the interstitial cells to produce testosterone. Testosterone and FSH stimulate the Sertoli cells and the spermatogonia, causing spermatogenesis. Sertoli cells release inhibin, which, along with testosterone, inhibits further release of FSH and LH, forming a negative feedback loop that keeps the rate of spermatogenesis and the concentration of testosterone in the blood nearly constant. Figure 40-15 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

Table 40-2 The Human Female Reproductive Tract Table 40-2 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

fimbria ovary uterus uterine tube endometrium (lining of uterus) urinary bladder cervix pubic bone vagina urethra FIGURE 40-16 The human female reproductive tract Eggs are produced in the ovaries and enter the uterine tube. Sperm and egg usually meet in the uterine tube, where fertilization and very early development occur. The early embryo embeds in the lining of the uterus, where development continues. The vagina receives sperm and serves as the birth canal. rectum clitoris anus labia Figure 40-16 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

fimbriae uterine tube ovary uterus FIGURE 40-17a The structures involved in oogenesis (a) External view of the ovary and uterine tube. uterus Figure 40-17a Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

fimbriae of 5 Ruptured uterine tube 4 Ovulated follicle secondary oocyte (egg) 6 Corpus luteum 7 Degenerating corpus luteum 3 Mature follicle with secondary oocyte ovary FIGURE 40-17b The structures involved in oogenesis (b) The development of follicles in an ovary, portrayed in a time sequence (clockwise from the lower right). (1) A primary oocyte begins development within a follicle. (2), (3) The follicle grows, providing both hormones and nourishment for the enlarging oocyte. (4) At ovulation the egg, surrounded by follicle cells, bursts through the ovary wall. (5), (6), (7) The remaining follicle cells develop into the corpus luteum, which secretes hormones. If fertilization does not occur, the corpus luteum disintegrates after a few days. 2 Developing follicles 1 New follicle containing primary oocyte Figure 40-17b Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

ovulating egg FIGURE 40-17c The structures involved in oogenesis (c) An egg is released from a follicle within the ovary. ovary Figure 40-17c Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

develops in fetus produced monthly beginning at puberty produced after fertilization egg secondary oocyte (egg) polar body oogonium primary oocyte FIGURE 40-18 Egg cells are formed by meiosis The oogonium undergoes mitosis and enlarges to form the primary oocytes. At meiosis I, most of the cytoplasm goes to the secondary oocyte, leaving a small polar body with chromosomes but little cytoplasm. At meiosis II, almost all the cytoplasm of the secondary oocyte goes to the egg, and a second small polar body discards the remaining "extra" chromosomes. The first polar body may also undergo the second meiotic division. In humans, meiosis II does not occur until a sperm penetrates the egg. polar body polar body polar body Mitosis Meiosis I Meiosis II Figure 40-18 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

Hypothalamic hormone level: 1 9 3 7 GnRH Pituitary hormone levels: 1 LH 4 FSH 7 In ovary 5 8 2 corpus luteum forms and matures corpus luteum degenerates follicle develops ovulation 3 Ovarian hormone levels 3 6 estrogen 9 FIGURE E40-1 Hormonal control of the menstrual cycle The menstrual cycle is generated by interactions among the hormones of the hypothalamus, the anterior pituitary, and the ovaries. The circled numbers correspond to those in the text. progesterone Uterine lining 1 menstruation 3 endometrial development 7 regeneration of endometrium 7 14 21 28 Figure E40-1 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

FIGURE 40-20b The secondary oocyte and fertilization (b) Sperm surround the oocyte, attacking its defensive barriers. Figure 40-20b Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

(a) Vasectomy (b) Tubal ligation Uterine tube is severed and ends are sealed Vas deferens is severed and ends are cauterized testis FIGURE 40-21 Sterilization (a) Vasectomy involves removing a short segment of the vas deferens and cauterizing the cut ends, blocking the transmission of sperm. (b) Tubal ligation involves removing a short segment of the uterine tube and blocking off the cut ends, preventing sperm from reaching the oocyte and the oocyte from reaching the uterus. ovary scrotum uterus Figure 40-21 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

Table 40-3 (part 1) Temporary Contraceptive Techniques Table 40-3 (part 1) Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

Table 40-3 (part 2) Temporary Contraceptive Techniques Table 40-3 (part 2) Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.

Identifique las partes del sistema reproductor masculino

Identifique las partes del sistema reproductorfemenino