SISTEMA REPRODUCTOR (LA IDEA FIJA) Copyright 2004 Pearson Education, Inc., publishing as Benjamin Cummings

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1 SISTEMA REPRODUCTOR (LA IDEA FIJA)

2 How male and female reproductive systems differentiate The reproductive organs and how they work How gametes are produced and fertilized Pregnancy, stages of development, birth & lactation Reproductive and developmental maturation and aging

3 Sex Determination: Overview Dimorphism: Males sperm Females eggs Chromosomes Autosomes Sex Chromosomes X - chromosome Y - chromosome Figure 26-1: Human chromosomes

4 Sex Determination: Overview Figure 26-2: Inheritance of X and Y chromosomes

5 Sexual Differentiation: Internal Embryonic Development Bipotential tissues: genes & hormones direct differentiation Gonad testis or ovary Wolffian duct Vas deferens, Mullerian duct oviduct

6 Sexual Differentiation: Internal Embryonic Development Figure 26-3a: Sexual development in the human embryo

7 Sexual Differentiation: External Genitalia Bipotential tissues: genital tubercle, urethral folds, urethral groove and labioscrotal swellings

8 Sexual Differentiation: External Genitalia Figure 26-3b: Sexual development in the human embryo

Determination of sex Determined genetically by two sex chromosomes: XY or XX. Y is dominant and contains the testis-determining gene product. Only one X is active.

9 Determination of sex Determined genetically by two sex chromosomes: XY or XX. Y is dominant and contains the testis-determining gene product. Only one X is active. The other X condenses to form the Barr body: Occasionally, more than one copy of X or Y occurs: XXX, XXY, XO or XX/XY mosaic being the four most common abnormalities.

10 Regulation of Reproduction: General Pathways Hypothalamus: pulse generator Gonadotropin releasing H (GnRH) Anterior Pituitary Lutenizing H (LH) Follicle stimulating H (FSH) Ovary: progesterone Estrogen, inhibin Testis: testosterone

11 Regulation of Reproduction: General Pathways Figure 26-7: General pattern of hormonal control of reproduction

12 Pathway for Sexual Development: Review for Genes to Organs Figure 26-4: Role of the SRY gene in male development

13 Hypothalamus-Pituitary-Gonadal Axis GnRH Hypothalamus GnRH Testosterone LH FSH Anterior Pituitary Oestrogen LH FSH Inhibin Inhibin Androgenic and anabolic effects Leydig Cells Sertoli Cells Testis Gonads Stimulatory Inhibitory Ovary Oestrogenic effects Theca interna Granulosa Androgens

19 Male Reproductive Anatomy and Physiology Testis Epididymis Vas deferens Seminal vesicle Prostate Bulbourethral Ejaculatory duct Urethra Penis

20 Components Testis => spermatozoa; testosterone production Epididymis => spermatozoa maturation & storage Ductus deferens & ampulla => transport & semen Accessory glands => semen a) Prostate gland b) Vesicular glands (seminal vesicles) c) Bulbourethral (Cowper s) gland d) Distal portion of ductus deferens (+/- ampulla) Urethra => transport Penis=> transport and ejaculation

21 Male Reproductive Anatomy and Physiology Figure 26-9a: ANATOMY SUMMARY: Male Reproduction

24 Spermatogenesis: Sperm Production in the Testis Seminiferous tubules Spermatids Spermatocytes Spermatozoa Sertoli cells Interstitial tissue Leydig cells Capillaries

25 Spermatogenesis: Sperm Production in the Testis Figure 26-9b-e: ANATOMY SUMMARY: Male Reproduction

26 Cells of Leydig S T Produce Androgens Interstitial cells mainly (of Leydig) Testosterone

27 Organization of Testis

28 Seminiferous Tubule and Interstitial Cells

29 Regulation of Spermatogenesis Figure 26-11: Hormonal control of spermatogenesis

30 Regulation of Spermatogenesis GnRH LH Leydig cells testosterone 2 0 sex charact. GnRH FSH Sertoli cells spermatoctye maturation Inhibin feedback FSH, testosterone short & long loops

31 Blood-Testis Barrier Adjacent sustentacular cells are joined by tight junctions Forms a diffusion barrier = controlled microenvironment for spermatogenesis Separates basal region from tubular compartment Spermatogonial cell division (mitosis) occurs in basal compartment Meiosis and spermiogenesis occurs in tubular compartment Blood-testis barrier prevents many substances from entering the tubular compartment Spermatocytes pass through the intercellular junctions to enter the tubular compartment

33 FSH RECEPTOR

34 Overview of Gametogenesis: Producing Eggs or Sperm Figure 26-5: Gametogenesis

35 Spermatozoa Structure and Functions in Review Head Acrosome: Nucleus: Midpiece Centrioles: Mitochondria: Tail: flagellum Microtubules: Figure 26-10: Sperm structure

39 LH & FSH RECEPTOR MUTATIONS

41 Female Reproductive Anatomy and Physiology: Overview Ovary Fallopian tube Fimbriae Uterus Cervix Endometrium Vagina Clitoris Labia

42 Female Reproductive Anatomy and Physiology: Overview Figure 26-12b: ANATOMY SUMMARY: Female Reproduction

43 Ovary: Details of Histology & Physiology Follicle Oocytes Thecal cells Granulosa cells Estrogen Corpus luteum Corpus luteum Progesterone Inhibin

44 Ovary: Details of Histology & Physiology Figure 26-12d: ANATOMY SUMMARY: Female Reproduction

45 Ovary: Details of Histology & Physiology Follicle Oocytes Thecal cells Granulosa cells Estrogen Corpus luteum Corpus luteum Progesterone Inhibin

46 Follicular Structure

47 Menstrual Cycle: Egg Maturation, and Endometrial Growth Follicular phase Egg matures Ovulation Egg released Luteal phase Corpus luteum Endometrium Prep for blastocyst No Pregnancy Menses Figure 26-13: The menstrual cycle

48 Figure The Hormonal Regulation of the Female Reproductive Cycle Figure 28.26a-c

49 The Hormonal Regulation of Ovarian Activity Figure 28.25

Follicular Growth Regulation GnRH rises in response to a decline in inhibin and sex steroids GnRH stimulates rise in pituitary FSH & LH secretion.

50 Follicular Growth Regulation GnRH rises in response to a decline in inhibin and sex steroids GnRH stimulates rise in pituitary FSH & LH secretion. FSH stimulates new follicle growth LH induces thecal cell growth, vascularization & androgen synthesis FSH stimulates granulosa cell production of E2 & LH receptor

51 Follicular Growth Regulation 2 LH act on thecal & granulosa cells and FSH acts on granulosa cells Late follicular phase has elevated follicular fluid E2, P, FSH and LH but low androgens

52 Endocrine Control of Menstrual Cycle: Follicular Phase FSH stimulates follicular development Estrogen: + feedback, limits more follicles

53 Endocrine Control of Menstrual Cycle: Ovulation Estrogen LH "surge" & FSH spike egg release Inhibin pushes FSH down, new follicle development

54 Ovulation The stigmata, a coneshaped protrusion of the follicle wall, appears just before ovulation Preovulatory follicular fluid has elevated E2, P, FSH, LH, oxytocin, plasmin activity & collaginase activity Extensive follicular vascularization occurs immediately prior to ovulation

55 Endocrine Control of Menstrual Cycle: Follicular Phase and Ovulation Figure 26-14a,b: Hormonal control of the menstrual cycle

56 Endocrine Control of Menstrual Cycle: Luteal phase Granulosa cells form corpus luteum progesterone progesterone & estrogen maintain endometrium Inhibin continues to limit new follicular development

57 Corpus Luteum Development 1 LH stimulates thecal & granulosa cell invasion of follicular cavity LH induces the luteinization of both cell types P synthesis increases as number of luteal cell increase

58 Corpus Luteum Development 2 LH stimulates increased P & E secretion FSH has no direct role in corpus luteum (CL) maintenance CL function depends on adequacy of follicle development (adequate induction by FSH of E2, LH and LDL receptor levels) Failure of adequate CL function results in luteal insufficiency

59 Corpus Luteum Development 3 Estrogen induces luteolysis Luteolysis causes decreased E2 & P secretion leading to decreased plasma levels Luteolysis continues in the absence of a fertilized ovum

60 Endocrine Control of Menstrual Cycle: Late Luteal phase Pregnancy: maintain progesterone, estrogen & inhibin No pregnancy: progesterone, estrogen & inhibin Menses, FSH & LH new follicle development

61 Endocrine Control of Menstrual Cycle: Luteal phase and Late Luteal phase Figure 26-14c, d: Hormonal control of the menstrual cycle

62 The Uterine Cycle Figure 28.20

63 The Hormonal Regulation of the Female Reproductive Cycle

64 Menstrual Cycle: Egg Maturation, and Endometrial Growth Follicular phase Egg matures Ovulation Egg released Luteal phase Corpus luteum Endometrium Prep for blastocyst No Pregnancy Menses Figure 26-13: The menstrual cycle

65 Overview of the Menstrual Cycle

REPRODUCCIÓN. La idea fija. Copyright 2004 Pearson Education, Inc., publishing as Benjamin Cummings

REPRODUCCIÓN. La idea fija. Copyright 2004 Pearson Education, Inc., publishing as Benjamin Cummings REPRODUCCIÓN La idea fija How male and female reproductive systems differentiate The reproductive organs and how they work How gametes are produced and fertilized Pregnancy, stages of development, birth