la idea fija - unq.edu.arcronos.unq.edu.ar/fisgen/reproduccion 2014.pdf · copyright © 2004...

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 & lactation

• Reproductive and developmental maturation and aging


Sex Determination: Overview

• Dimorphism:

• Males sperm

• Females eggs

• Chromosomes

• Autosomes

• Sex Chromosomes

• X - chromosome

• Y - chromosome Figure 26-1: Human chromosomes


Sex Determination: Overview

Figure 26-2: Inheritance of X and Y chromosomes


• Bipotential tissues: genes & hormones direct differentiation:

Sex-determining Region Y Testis Determining Factor

• Gonad testis or ovary

• Wolffian duct Vas deferens,

• Mullerian duct oviduct

Sexual Differentiation: Internal Embryonic Development


Sexual Differentiation: Internal Embryonic Development

Figure 26-3a: Sexual development in the human embryo


Pathway for Sexual Development: Review for Genes to Organs

Figure 26-4: Role of the SRY gene in male development


• Bipotential tissues: genital tubercle, urethral folds, urethral groove and labioscrotal swellings

Sexual Differentiation: External Genitalia


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 codifies the testis-determining gene product.

• Only one X is active. The other X condenses to form the Barr body.


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, inhibin


Regulation of Reproduction: General Pathways

Figure 26-7: General pattern of hormonal control of reproduction


Hypothalamus-Pituitary-Gonadal Axis

GnRH GnRHHypothalamus

Androgenicand anabolic

effects

Oestrogeniceffects

Testis Ovary

Stimulatory

Inhibitory

AnteriorPituitaryLH LH

FSH FSH

LeydigCells

Thecainterna

SertoliCells

Granu-losa

Inhibin Inhibin

Testosterone Oestrogen

Androgens

Gonads


Male Reproductive 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

• Urethra => transport

• Penis=> transport and ejaculation


Male Reproductive Anatomy and Physiology

Figure 26-9a: ANATOMY SUMMARY: Male Reproduction

Seminal

vesicles


Semen


Spermatogenesis: Sperm Production in the Testis

• Seminiferous tubules

• Spermatids

• Spermatocytes

• Spermatozoa

• Sertoli cells

• Interstitial tissue

• Leydig cells

• Capillaries


Spermatogenesis: Sperm Production in the Testis

Figure 26-9b-e: ANATOMY SUMMARY: Male Reproduction


Interstitial cells

(of Leydig)

Cells of

Leydig

Produce

Androgens—

mainly

Testosterone


Seminiferous Tubule and Interstitial Cells


Regulation of Spermatogenesis

Figure 26-11: Hormonal control of spermatogenesis


• GnRH LH Leydig cells testosterone 20 sex charact.

• GnRH FSH Sertoli cells spermatoctye maturation

• Inhibin feedback – FSH, testosterone – short & long loops

Regulation of Spermatogenesis


Female Reproductive Anatomy and Physiology: Overview

• Ovary

• Fallopian tube

• Fimbriae

• Uterus

• Cervix

• Endometrium

• Vagina

• Clitoris

• Labia


Female Reproductive Anatomy and Physiology: Overview

Figure 26-12b: ANATOMY SUMMARY: Female Reproduction


Ovary: Details of Histology & Physiology

• Follicle

• Oocytes

• Thecal cells

• Granulosa cells

• Estrogen

• Corpus luteum

• Corpus luteum

• Progesterone

• Inhibin



Figure 26-12d: ANATOMY SUMMARY: Female Reproduction



• Follicle

• Oocytes

• Thecal cells

• Androgens

• Granulosa cells

• Estrogens

• Corpus luteum

• Corpus luteum

• Progesterone

• Inhibin

Folículos ováricos

Región medular Región cortical


Follicular Structure


Menstrual Cycle: Egg Maturation, and Endometrial Growth

Figure 26-13: The menstrual cycle

• Follicular phase

• Egg matures

• Ovulation

• Egg released

• Luteal phase

• Corpus luteum

• Endometrium

• Prep for blastocyst

• No Pregnancy

• Menses

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 28.26a-c

Figure 28.26 The Hormonal Regulation of the Female Reproductive Cycle

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 28.25

The Hormonal Regulation of Ovarian Activity

ovulación


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


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


• FSH stimulates follicular development

• Estrogen: + feedback, limits more follicles

Endocrine Control of Menstrual Cycle: Follicular Phase


• Estrogen LH "surge" & FSH spike egg release

• Inhibin pushes FSH down , new follicle development

Endocrine Control of Menstrual Cycle: Ovulation


Ovulation

• The stigmata, a cone-shaped 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


• Granulosa cells form corpus luteum E2, progesterone

• progesterone & estrogen maintain endometrium

• Inhibin continues to limit new follicular development

Endocrine Control of Menstrual Cycle: Luteal phase


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



• 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



• Estrogen induces luteolysis

• Luteolysis causes decreased E2 & P secretion leading to decreased plasma levels

• Luteolysis continues in the absence of a fertilized ovum


• Pregnancy: maintain progesterone, estrogen & inhibin

• No pregnancy: progesterone, estrogen & inhibin

• Menses, FSH & LH new follicle development

Endocrine Control of Menstrual Cycle: Late Luteal phase


Endocrine Control of Menstrual Cycle: Luteal phase and Late Luteal phase

Figure 26-14c, d: Hormonal control of the menstrual cycle


Menstrual Cycle: Egg Maturation, and Endometrial Growth

Figure 26-13: The menstrual cycle

• Follicular phase

• Egg matures

• Ovulation

• Egg released

• Luteal phase

• Corpus luteum

• Endometrium

• Prep for blastocyst

• No Pregnancy

• Menses


Overview of the Menstrual Cycle

la idea fija - unq.edu.arcronos.unq.edu.ar/fisgen/reproduccion 2014.pdf · copyright © 2004...

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