Chapter 26b Reproduction and Development

Male Reproductive Structures External genitalia Penis and scrotum Common passageway Urethra Accessory glands and ducts Prostate gland Seminal vesicle Bulbourethral gland

Figure 26-8 (1 of 2) Male Reproductive Structures - Overview

Figure 26-8 (2 of 2) Male Reproductive Structures - Erectile Tissues

Male Reproductive Structures Testes (sperm production) Seminiferous tubules Epididymis (sperm maturation) Vas deferens (aka “ductus deferens”, a passageway into abdomen and delivery to the urethra)

Figure 26-9a Male Reproductive Structures - Sagittal View Urethra Scrotum Testis Rectum Ureter Urinary bladder Prostate gland Ejaculatory duct Bulbourethral gland Vas deferens Pubic symphysis Epididymis Seminal vesicle Penis (a) ANATOMY SUMMARY THE MALE REPRODUCTIVE SYSTEM

Figure 26-9b Male Reproductive Structures - Scrotal Structures Head of epididymis Seminiferous tubule Vas deferens Epididymis Scrotal cavity (b) ANATOMY SUMMARY THE MALE REPRODUCTIVE SYSTEM

Figure 26-9c Seminiferous Tubule - Cross-Section Spermatogonium Capillary Leydig cell (c) Sertoli cell ANATOMY SUMMARY THE MALE REPRODUCTIVE SYSTEM

Spermatogenesis in the Testes Seminiferous tubules Sertoli cells surround and support developing sperm Spermatogonia divide and produce all sperm cells Primary and secondary spermatocytes Spermatids Spermatozoa Interstitial tissues support spermatogenesis Leydig cells  testosterone Capillaries deliver nutrients and remove wastes

Figure 26-9d Seminiferous Tubule - Detail Sertoli cells Spermatozoa Spermatids Secondary spermatocyte Primary spermatocyte Spermatogonium Leydig cells Capillary Fibroblast Basal lamina Lumen of seminiferous tubule (d) Tight junction between Sertoli cells ANATOMY SUMMARY THE MALE REPRODUCTIVE SYSTEM

Figure Spermatozoa Structure Tail (flagellum) Mid piece Head Microtubules Mitochondrial spiral Centrioles Nucleus Acrosome contains enzymes

Regulation of Spermatogenesis Hormones control the production of sperm GnRH stimulates the release of LH and FSH LH  Leydig cells  testosterone FSH  Sertoli cells  cell products

Figure Regulation of Spermatogenesis LH GnRH Hypothalamus Anterior pituitary Inhibin Testes Leydig cells Testosterone (T) To body for secondary effects FSH Sertoli cell Cell products Second messenger Sertoli cell ABPT Androgen-binding protein (ABP) Spermatogonium Spermatocyte

Accessory Glands Contribute to Semen Accessory glands contribute 99% of semen volume, as well as the following Seminal vesicles – fructose, vitamin C, prostaglandins Prostate gland – buffers, citric acid, enzymes Bulbourethral gland – mucus, buffers

Table 26-3 Accessory Glands Contribute to Semen

Female Reproductive System Female reproduction is a cyclic process Hormones from the hypothalamus and anterior pituitary stimulate the ovaries The ovaries release estrogen and progesterone in varying patterns during each cycle Ovulation releases a mature oocyte monthly Estrogen and progesterone prepare the uterus for possible pregnancy

Female Reproductive Structures External genitalia (aka vulva, or pudendum) Labia majora Labia minora Clitoris Vagina Hymen Urethral opening is inside the labia minora

Figure 26-12a Female Structures - External Genitalia Vagina Hymen (stretched) Anus Labium majora Labium minora Clitoris Urethral opening THE FEMALE REPRODUCTIVE SYSTEM ANATOMY SUMMARY (a)

Female Structures - Internal Organs Vagina Uterus Cervix Endometrium and myometrium Fallopian tube Fimbriae Ovary

Uterus Ovary Urinary bladder Fallopian tube Rectum Cervix Anus Clitoris Labium majora Labium minora Vagina Urethra THE FEMALE REPRODUCTIVE SYSTEM ANATOMY SUMMARY (b) Figure 26-12b Female Structures - Sagittal View

Ovaries: Cells and Tissues Follicle - structure where oocytes develop Granulosa cells Oocyte Thecal cells surround all follicles Corpus luteum

Figure 26-12c–e Structure of the Uterus and Ovary

Figure 26-12c, f Structure of the Uterine Wall

Phases of the Ovarian Cycle Follicular phase Proliferation of granulosa cells Development of antrum Maturation of oocyte Ovulation Ripened follicle bursts, releasing oocyte Luteal phase Ruptured follicle develops into corpus luteum

Figure (1 of 2) The Ovarian Cycle

Endometrial Lining: the Uterine Cycle Menses (occurs if pregnancy is not achieved) Bleeding from uterus as endometrium is shed Proliferative phase Endometrium grows in preparation for pregnancy Secretory phase Endometrial secretions promote implantation

Figure (2 of 2) The Uterine Cycle

Figure (1 of 4) DAYS /0 Follicular Phase Phases of the Uterine Cycle Phases of the Ovarian Cycle Basal body temperature (–C) Uterine cycle Ovarian hormone levels Ovarian cycle Gonadotrophic hormone levels Primary follicle Theca MENSES Inhibin Estrogen LH FSH Progesterone Follicular Phase and Menses

Figure (2 of 4) DAYS /0 Follicular Phase Phases of the Uterine Cycle Phases of the Ovarian Cycle Basal body temperature (–C) Uterine cycle Ovarian hormone levels Ovarian cycle Gonadotrophic hormone levels Primary follicle Theca MENSES PROLIFERATIVE PHASE Inhibin Estrogen Antrum LH FSH Progesterone Follicle Maturation and the Proliferative Phase

DAYS /0 Follicular Phase Ovulation Luteal Phase Phases of the Uterine Cycle Phases of the Ovarian Cycle Basal body temperature (–C) Uterine cycle Ovarian hormone levels Ovarian cycle Gonadotrophic hormone levels Primary follicle Theca Ovulation Corpus luteum formation MENSES PROLIFERATIVE PHASE SECRETORY PHASE Inhibin Estrogen Antrum LH FSH Progesterone Figure (3 of 4) Ovulation, Luteal Phase, and Secretory Phase

DAYS /0 Follicular Phase Ovulation Luteal Phase Phases of the Uterine Cycle Phases of the Ovarian Cycle Basal body temperature (–C) Uterine cycle Ovarian hormone levels Ovarian cycle Gonadotrophic hormone levels Primary follicle Theca Ovulation Corpus luteum formation Mature corpus luteum Corpus albicans Progesterone MENSES PROLIFERATIVE PHASE SECRETORY PHASE Inhibin Estrogen Antrum LH FSH Figure (4 of 4) Corpus Luteum Degenerates and Ceases Hormone Production

Complex Hormonal Control of Two Cycles Ovarian and uterine cycles are controlled by several hormones, which display complex interactions Extra-ovarian hormones GnRH from the hypothalamus FSH and LH from the anterior pituitary Ovarian hormones Estrogen Progesterone

Figure LHFSH GnRH Androgens Estrogens (a) Early to mid-follicular phase Follicle Granulosa cells Thecal cells (b) Late follicular phase and ovulation (d) Late luteal phase FSHLH New follicles begin to develop Corpus luteum dies Tonic secretion resumes Corpus luteum Progesterone Ovum LH FSH Follicle Estrogen and progesterone FSHLH Corpus luteum (from ovulated follicle) Estrogen Progesterone Inhibin GnRH secretes (c) Early to mid-luteal phase Estrogen Inhibin Follicle Granulosa cells Thecal cells Inhibin High estrogen output Small amount of progesterone Androgens LHFSH GnRH Pituitary Hypothalamus Hormonal Control of the Menstrual Cycle

Hormonal Control of the Menstrual Cycle: Follicular Phase FSH stimulates follicular development Maturation to secondary and tertiary follicles Granulosa cells produce estrogen Negative feedback decreases FSH and LH secretion Positive feedback allows continued estrogen production LH stimulates thecal cells to produce androgens Aromatase converts androgens into estrogens Antrum fills with fluid

LHFSH GnRH Androgens Estrogens (a) Early to mid-follicular phase Follicle Granulosa cells Thecal cells Corpus luteum Progesterone Ovum LH FSH Follicle Estrogen Inhibin Pituitary Hypothalamus Figure (1 of 4) Hormonal Control of the Menstrual Cycle: Follicular Phase

Hormonal Control of the Menstrual Cycle: Late Follicular Phase and Ovulation Late follicular phase Secretion of inhibin and progesterone begins Estrogen changes from negative to positive feedback Enhanced secretion of LH - the LH surge Meiosis resumes in developing follicles Ovulation Mature follicle secretes collagenase Inflammatory reaction produces prostaglandins Follicle ruptures releasing mature oocyte Theca and granulosa cells change into luteal cells

LHFSH GnRH Androgens Estrogens (a) Early to mid-follicular phase Follicle Granulosa cells Thecal cells (b) Late follicular phase and ovulation Corpus luteum Progesterone Ovum LH FSH Follicle Estrogen Inhibin Follicle Granulosa cells Thecal cells Inhibin High estrogen output Small amount of progesterone Androgens LHFSH GnRH Pituitary Hypothalamus Figure (2 of 4) Hormonal Control of the Menstrual Cycle: Late Follicular Phase and Ovulation

Hormonal Control of the Menstrual Cycle: Early to Mid-Luteal Phase Corpus luteum develops and secretes progesterone and estrogen Progesterone and estrogen exert negative feedback on hypothalamus Effects of progesterone Endometrium develops further Cervical mucus thickens

LHFSH GnRH Androgens Estrogens (a) Early to mid-follicular phase Follicle Granulosa cells Thecal cells (b) Late follicular phase and ovulation Corpus luteum Progesterone Ovum LH FSH Follicle FSHLH Corpus luteum (from ovulated follicle) Estrogen Progesterone Inhibin GnRH secretes (c) Early to mid-luteal phase Estrogen Inhibin Follicle Granulosa cells Thecal cells Inhibin High estrogen output Small amount of progesterone Androgens LHFSH GnRH Pituitary Hypothalamus Figure (3 of 4) Hormonal Control of the Menstrual Cycle: Early to Mid-Luteal Phase

Hormonal Control of the Menstrual Cycle: Late Luteal Phase If no implantation Corpus luteum undergoes apoptosis after 12 days Lack of progesterone leads to death of endometrium Menses = sloughing of the dead endometrium FSH and LH secretion resumes Following implantation hcG maintains corpus luteum Corpus luteum secretes progesterone and estrogen

LHFSH GnRH Androgens Estrogens (a) Early to mid-follicular phase Follicle Granulosa cells Thecal cells (b) Late follicular phase and ovulation (d) Late luteal phase FSHLH New follicles begin to develop Corpus luteum dies Tonic secretion resumes Corpus luteum Progesterone Ovum LH FSH Follicle Estrogen and progesterone FSHLH Corpus luteum (from ovulated follicle) Estrogen Progesterone Inhibin GnRH secretes (c) Early to mid-luteal phase Estrogen Inhibin Follicle Granulosa cells Thecal cells Inhibin High estrogen output Small amount of progesterone Androgens LHFSH GnRH Pituitary Hypothalamus Figure (4 of 4) Hormonal Control of the Menstrual Cycle: Late Luteal Phase

Female Secondary Sex Characteristics Secondary sexual characteristics are traits, other than genitalia, that distinguish males from females Characteristics controlled by estrogen Breast development Distribution of body fat Adrenal androgens control some female traits Growth of pubic and axillary hair Sex drive (libido)