Chapter 22 Structure and Function of the Reproductive

Chapter 22 Structure and Function of the Reproductive Systems Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 1

Development of the Reproductive Systems Dependent on sex hormones Ø Males—testosterone • 6 to 7 weeks’ gestation, male embryos differentiate under the influence of testes-determining factor (TDF) Ø Females—estrogen, FSH, and LH • Gonads produce estrogen; in the absence of testosterone, • • • there is a loss of the wolffian system, and the two gonads develop into ovaries Gonadotropin-releasing hormone (Gn. RH) produced in the hypothalamus by 10 weeks’ gestation controlling the production of the gonadotropins LH and FSH levels rise until 28 weeks, stimulating estrogen and progesterone production Gonadostat-negative feedback mechanism controls Gn. RH Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 2

Development of the Reproductive Systems Sexual differentiation in utero Homologous structures Ø Gonads Ø Ducts • Mesonephric • Paramesonephric Ø Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 3

Development of the Reproductive Systems Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 4

Development of the Reproductive Systems Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 5

Development of the Reproductive Systems Puberty Exact trigger unknown Ø Females • Dehydroepiandrosterone (DHEA) and its sulfate (DHAS) • Begins with thelarche (breast development) in females Ø Adrenarche Ø Gonadarche Ø Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 6

Development of the Reproductive Systems Puberty Accelerated growth followed by thelarche • 9 years of age in white girls • 8 years of age in black girls Ø Early puberty in girls linked to: • Obesity • Increased levels of leptin (a hormone secreted from adipose Ø tissue); regulates appetite Ø Leptin levels increase until puberty, then decrease as puberty advances • Contributes to increased adipose tissue, allowing maturation to occur Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 7

Development of the Reproductive Systems Puberty Ø Males—testes begin to produce mature sperm • Male puberty complete with the first ejaculation that contains mature sperm Ø Females—ovaries begin to release mature ova • Female puberty complete at first ovulatory menstrual period Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 8

Development of the Reproductive Systems Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 9

Female Reproductive System External genitalia (vulva) Mons pubis Ø Labia majora Ø Labia minora Ø Clitoris Ø Vestibule Ø Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 10

Female Reproductive System External genitalia (vulva) Introitus Ø Hymen Ø Urinary meatus Ø Lesser vestibular glands (Skene glands) Ø Greater vestibular glands (Bartholin glands) Ø Perineum Ø Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 11

External Genitalia (Vulva) Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 12

Internal Genitalia Vagina Uterus Fallopian tubes Ovaries Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 13

Internal Genitalia Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 14

Uterine Position Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 15

Internal Genitalia Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 16

Ovary Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 17

Follicle Development Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 18

Female Sex Hormones Estrogens Estradiol Ø Estrone Ø Estriol Ø Progesterone Androgens Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 19

Menstrual Cycle Menarche Menopause Phases Menstruation (menses) Ø Follicular/proliferative phase Ø Luteal/secretory phase Ø Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 20

Menstrual Cycle Ovarian cycle Uterine phases Vaginal response Body temperature change Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 21

Menstrual Cycle Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 22

Male Reproductive System Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 23

Male Reproductive System External genitalia Ø Testes • Essential organs of reproduction Produce gametes Produce sex hormones (androgens, testosterone) Suspended outside the pelvic cavity – Sperm production requires an environment that is 1° or 2° C cooler than body temperature Epididymis Ø Scrotum Ø Penis Ø Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 24

Male Reproductive System Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 25

Male Reproductive System Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 26

Male Reproductive System Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 27

Male Reproductive System Internal genitalia Seminal vesicles Ø Prostate gland Ø Bulbourethral glands Ø Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 28

Male Internal Genitalia Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 29

Spermatogenesis Spermatogonia Primary spermatocytes Secondary spermatocytes Spermatids Sertoli cells Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 30

Spermatogenesis Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 31

Male Reproductive System Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 32

Male Sex Hormones Androgens Primary androgen—testosterone Ø Produced mainly in Leydig cells of the testes Ø Testosterone • Sexual differentiation • Urogenital system development • Nervous and skeletal tissue development • Sex drive Ø Dihydrotestosterone and prolactin Ø Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 33

Male Sex Hormones secreted at each level of the hypothalamic-pituitary-testicular (H-P-T) axis Control and coordinate testicular function Ø Positive and negative feedback signals • Sex steroids inhibit hypothalamic Gn. RH secretion and pituitary LH responsiveness to Gn. RH • Testicular inhibin that inhibits pituitary FSH and, possibly, circulating estrogens Disruption along the H-P-T axis may lead to hypogonadism or infertility Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 34

Structure and Function of the Breast Modified sebaceous glands on the ventral surface of the thorax Female breast Ø Ø Ø Nipple Areola Glands of Montgomery Male breast Ø Ø Until puberty, male and female development is similar Without sufficient influence of estrogen and progesterone, male breast does not develop any further Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 35

Structure and Function of the Breast Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 36

Structure and Function of the Breast Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 37

Tests of Reproductive Function Infection and cancer tests Culture Ø Serologic testing Ø Tissue biopsy Ø Needle biopsy Ø Papanicolaou (Pap) test Ø Mammography Ø Fertility tests Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 38

Aging and the Female Reproductive System Menopause Perimenopause Vasomotor symptoms Ø Vasomotor flush • Associated with fluctuation in estrogen levels not just estrogen loss Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 39

Aging and the Male Reproductive System Reproductive capacity longer than woman’s No event comparable to menopause Decreased erectile and ejaculatory function Testes atrophy, decrease in weight, and soften Decreased levels of gonadotropins and testosterone Mosby items and derived items © 2010, 2006 by Mosby, Inc. , an affiliate of Elsevier Inc. 40