Ch 28 Lecture Study Guide 1. List the characteristics of the reproductive system. Only organ system not essential to life Ensures continued existence of human species Produces, stores, nourishes, and transports male and female reproductive cells (gametes) Produces reproductive hormones 2. In what way are the male and female reproductive systems very different? Female produces 1 gamete/month Retains and nurtures zygote Male produces large quantities of gametes 500M/day! Begins at puberty and continues past age 70 3. What do the male gonads (testes) produce? Produce male gametes (spermatozoa, sperm) Produce hormones Male sex hormones (androgens, primarily testosterone) Inhibin 4. What is emission? Movement of mature spermatozoa move through male duct system, are mixed with secretions of accessory glands 5. What is semen? Sperm mixed with accessory gland secretions 6. What are the female gonads (ovaries) responsible for? Release 1 immature gamete (oocyte) each month Produce hormones Female sex hormones (estrogens, progestins) Inhibin 7. The uterine tube carries the oocyte to the uterus.
8. What happens if sperm reaches the oocyte in the uterine tube? Fertilization is initiated Oocyte matures into ovum 9. During sexual intercourse, ejaculation introduces ejaculation into the vagina. 10. What are the general course of events that occur in human reproduction once semen is introduced into the vagina? 1. Spermatozoa ascend female reproductive tract Seek out oocyte (generates heat, attracts sperm like heat seeking missile) 2. If fertilization occurs in uterine tube: sperm + ovum zygote 3. Zygote travels to uterus 4. Uterus encloses/supports developing embryo 5. Embryo grows into fetus and prepares for birth 11. Define gamete. Reproductive cells (spermatozoa or oocyte) that contain half the normal chromosome complement 12. Define gametogenesis. Formation of gametes 13. A female gamete is called an oocyte and is produced during development (before birth). 14. A male gamete is called a spermatozoa (sperm) and is produced during lifetime (begins at puberty and continues past age 70. 15. In males and females, gametogenesis involves mitosis and meiosis. 16. What is mitosis? What does it produce? Process of somatic cell division Produces 2 diploid daughter cells Have same number of (paired) chromosomes as parent cell, i.e., 46 (23 x 2)
17. What is meiosis? What does it produce? reduction division Special cell division involved in gamete production Produces 2 haploid daughter cells Have one half (unpaired) the number of chromosomes in the parent cell, i.e., 23 18. When does mitosis occur? What is mitosis not limited to? Mitosis occurs during division of somatic (body) cells and is not limited to gametogenesis 19. Meiosis is only involved in the production of sex cells. 20. What does meiosis involve? Involves two cycles of cell division Chromosomes (each with two chromatids) pair up = tetrad During first division, tetrads split During second division, chromatids split 21. What does meiosis produce? Produces gametes with one half the number of chromosomes, i.e., 23 22. Why is it okay that meiosis produces gametes with one half the normal number of chromosomes? Fusion of male gamete (sperm) and female gamete (oocyte) produces cell with correct number of chromosomes (diploid), i.e., 46 (23 from each parent) 23. What does each process of gametogenesis in males produce? (Gametogenesis begins with stem cells called spermatogonium). Mitotic division produces Primary spermatocyte + stem cell Meiosis I produces Secondary spermatocyte Meiosis II produces Spermatid (undifferentiated male gametes Spermiogenesis produces Spermatozoa (sperm)
24. What does each process of gametogenesis in females produce? (Gametogenesis begins with stem cells called oogonium). Mitotic division produces Primary oocyte Meiosis I produces Secondary oocyte + polar body Meiosis II produces Ovum + polar body (after fertilization) Spermiogenesis produces N/A females do not produce sperm 25. Define spermatogenesis. Process of spermatozoa (sperm) development 26. What 3 integrated processes are involved in spermatogenesis? 1. Mitosis 2. Meiosis 3. Spermiogenesis 27. Where does spermatogenesis occur? Occurs in seminiferous tubules (ST) in testes 28. Briefly describe what occurs during mitosis in spermatogenesis. Spermatogonium (stem cell) spermatogonium + primary spermatocyte Primary spermatocyte pushed toward lumen of ST On going throughout lifetime 29. Briefly describe what occurs during meiosis in spermatogenesis. Primary spermatocyte first division secondary spermatocytes second division spermatids = undifferentiated male gametes Each primary spermatocyte 4 spermatids 30. Define spermiogenesis. Last stage of spermatogenesis Begins with spermatids small, relatively unspecialized cells Physical maturation of spermatids Involves major structural changes Differentiate into mature spermatozoa Highly specialized cells
31. Define spermiation. When spermatozoa: Detach from Sertoli cells Enter lumen of ST 32. How long does it take from spermatogonium to spermiation? From spermatogonium to spermiation in 9 weeks 33. Matching: YOU WILL USE THE SOME CHOICES BELOW MORE THAN ONCE. B Flagellum; provides motility A. Testosterone D Nurse cells B. Tail of spermatozoon A Maintains accessory glands and organs C. Middle piece of spermatozoon G Contains enzymes to dissolve oocyte wall D. Sustentacular cells F Large cells in interstitial spaces between ST E. Head of spermatozoon A Stimulates metabolism, esp. protein synthesis (m. growth) F. Interstitial (Leydig) cells A Stimulates spermatogenesis and spermatozoa maturation G. Acrosomal cap of spermatozoon D Extend between other cells from ST capsule to lumen H. Spermatozoon C Contains mitochondria for energy to move tail A Secreted by Interstitial (Leydig) cells F Stimulated by LH to produce androgens H Has no energy reserves; uses nutrients from surrounding fluids A Affects CNS, including libido (sex drive) F Responsible for production of androgens E Nucleus with chromosomes (DNA) D Sertoli cells A Establishes/maintains secondary sex characteristics D Surround developing spermatocytes & spermatids in ST H Loses all other organelles to make light weight 34. What are the interstitial (Leydig) cells? Large cells in interstitial spaces between ST responsible for the production of the androgen, testosterone. 35. List the functions of testosterone. 1. Stimulates spermatogenesis and spermatozoa maturation 2. Affects CNS, including libido (sexual drive) 3. Stimulates metabolism, especially protein synthesis, muscle growth 4. Establishes/maintains secondary sex characteristics, e.g., facial hair 5. Maintains male accessory glands and organs
36. What are the sustentacular cells? List AKAs. Nurse cells /Sertoli cells Extend between other cells from ST capsule to lumen Surround developing spermatocytes and spermatids in ST 37. List the 6 major functions of the sustentacular cells and briefly describe each. 1. Maintain blood testis barrier Cells joined by tight junctions Isolates STs 2. Support mitosis and meiosis Cells stimulated by FSH (and presence of T) Promote spermatogenesis 3. Support spermiogenesis Provide nutrients for development Phagocytize cytoplasm shed by spermatids 4. Produce inhibin Stimulated by factors released by developing spermatozoa Provides feedback control of spermatogenesis Inhibits (decreases) production of FSH by AP 5. Produce androgen binding protein (ABP) Stimulated by FSH Binds T in ST fluid, elevates levels 6. Secrete Mullerian inhibiting factor (MIF) Causes regression of fetal ducts that form uterine tubes and uterus 38. What are the functions of the epididymis? Monitors and adjusts composition of ST fluid Recycles damaged spermatozoa Stores/protects spermatozoa and facilitates functional maturation 39. Why is the epididymis important to the survival of spermatozoa? Spermatozoa in ST functionally immature Incapable of fertilization or locomotion Become mature in epididymis (but not motile)
40. What must a spermatozoa undergo to become motile? Explain. To become motile, spermatozoa must undergo capacitation Become motile when mixed with seminal vesicle fluid Capable of successful fertilization when exposed to female reproductive tract 41. What does capacitation mean? Sperm maturation 42. What are the functions of the ductus deferens? List any AKAs. Transport spermatozoa from epididymis to urethra Store spermatozoa (several months) In state of suspended animation Low metabolic rates 43. What is seminal fluid? Which accessory glands contribute to the production of seminal fluid? How much does each accessory gland contribute? A mixture of secretions from several glands including: Seminal vesicles (60%) Prostate gland (20 30%) Bulbourethral glands (10 20%) 44. List the accessory glands of the male reproductive system. 1. Seminal vesicles 2. Prostate gland 3. Bulbourethral glands 45. What do the secretions of the seminal vesicles contain? 1. High concentrations of fructose (easily metabolized by spermatozoa) 2. Prostaglandins stimulate smooth muscle contractions in male and female reproductive tracts 3. Fibrinogen forms temporary clot in vagina after ejaculation (seminal plug) 46. What is the primary source of energy for spermatozoa? Fructose
47. What effect do secretions from the seminal vesicles have on functional spermatozoa? Secretions make functional spermatozoa motile (flagella begins beating) 48. When are secretions from the seminal vesicles discharged into the ejaculatory duct? Secretions discharged into ejaculatory duct at emission (due to contractions in ductus deferens, SVs, and prostate gland) 49. What does the prostate gland produce? Into what is it ejected? Produces prostatic fluid, which contains seminalplasmin = antibiotic that may help prevent urinary tract infections Ejected into prostatic urethra 50. What are the bulbourethral glands? List any AKAs. What functions do their secretions perform? Mucous glands Secretions Help neutralize urinary acids remaining in urethra Lubricate glans (tip of) penis 51. Define ejaculate. The volume of fluid released at ejaculation (usually 2 5 ml of semen) 52. What does the fluid, semen contain/what are the components of semen? 1. Spermatozoa Sperm count = 20 100 million/ml semen (ideally > 60 million/ejaculate) 2. Seminal fluid = mixture of glandular secretions from: SV (60%) Prostate (30%) Bulbourethral glands (5%) Sustentacular cells and epididymis (5%) 3. Enzymes Protease helps dissolve vaginal mucous secretions Seminalplasmin (from prostate) Prostatic enzyme converts fibrinogen to fibrin after ejaculation Fibrinolysin liquefies clotted semen
53. Explain the role that the hypothalamus plays in the male reproductive system. Hypothalamus GnRH ant pit Ant pit LH (ICSH) interstitial (Leydig) Cells testosterone (T) FSH Testosterone + FSH sustentacular cells Synthesis of ABP (Androgen binding protein binds androgens, primarily testosterone, in the fluid contents of the STs. Thought to be important in elevating concentration of androgens within the STs and stimulating spermatogenesis) Stimulation of spermatogenesis and spermiogenesis 54. How do the sustentacular cells (the target cells of FSH) regulate the production of FSH? Factors released by developing spermatozoa sustentacular cells inhibin inhibits (decreases) FSH production by AP 55. List the physiological effects of testosterone. 1. Stimulates spermatogenesis (with FSH) 2. Maintains male accessory glands and organs 3. Establishes/maintains secondary sex characteristics 4. Stimulates anabolic metabolism, especially bone and muscle growth, RBC formation 5. On CNS, including libido (sexual drive) 56. In males, why is there an narrow range of plasma FSH, LH and testosterone? In males, GnRH pulse frequency relatively steady narrow range of plasma FSH, LH, T 57. As testosterone secretion accelerates at puberty, what happens? T secretion accelerates at puberty Sexual maturation Appearance of secondary sex characteristics 58. How is testosterone production controlled? Negative feedback controls T production Inc T inhibits release of GnRH dec LH dec T 59. List the functions of the female reproductive system. 1. Produces gametes and reproductive hormones 2. Protects and supports developing embryo 3. Nourishes newborn infant
60. Define and describe oogenesis. Ovum production 61. Compare oogenesis to spermatogenesis. Before birth Mitotic divisions complete Oogonia (stem cells) primary oocytes (vs. ongoing throughout lifetime in males) Primary oocytes begin meiosis I Cytoplasm of oocyte unevenly distributed during 2 meiotic divisions; produces: One functional ovum (with most of original cytoplasm) 2 3 polar bodies = nonfunctional cells that later disintegrate (vs. primary spermatocyte 4 spermatozoa) Ovary releases secondary oocyte instead of mature ovum Meiosis not completed unless/until fertilization 62. List the characteristics of primary oocytes. Are daughter cells of oogonia (stem cells) Located in ovarian cortex in clusters (egg nests) Surrounded by follicle cells = primordial follicle 2 M primary oocytes at birth Meiosis I (primary oocyte secondary oocyte) Begins during fetal development Stops early in meiosis I (suspended development) Doesn t continue until after puberty (numbers reduced to 400,000 due to atresia) 63. What generally occurs during the ovarian cycle? 1. Formation of primary follicles 2. Formation of secondary follicles 3. Formation of tertiary follicle 4. Ovulation 5. Formation of corpus luteum 6. Formation of corpus albicans 64. When does the ovarian cycle begin? Why? Begins after puberty when groups of primordial follicles develop into primary follicles each month Process begins due to increased FSH at puberty
65. What are the 2 phases of the ovarian cycle? Involves 2 phases Follicular (preovulatory) phase Luteal (postovulatory) phase 66. What generally occurs during the follicular phase of the ovarian cycle? List aka for follicular phase. Aka: preovulatory phase Formation of primary follicles Formation of secondary follicles Formation of tertiary follicle primary oocyte completes meiosis I (just before ovulation) Primary oocyte undergoes (meiotic division) producing secondary oocyte and polar body Secondary oocyte enters meiosis II Secondary oocyte and surrounding granulosa cells lose connections with follicular wall 67. What occurs in the formation of primary follicles in the follicular phase? Every month AP FSH some primordial follicles (with primary oocyte) primary follicles (with primary oocyte) 68. What is the zona pellucida? Glycoprotein layer around primary oocyte 69. What are granulosa cells? Rounded, larger follicle cells outside zona pellucida 70. What are thecal cells? Layer of follicle cells adjacent to ovarian stroma 71. What do the granulosa and thecal cells work together to produce? Estrogen (continues in all follicles) 72. What happens during the formation of secondary follicles during the follicular phase? Each month, only a few (1 3) primary follicles become secondary follicles Primary oocyte increases in size Follicle wall thickens Granulosa cells secrete follicular fluid Follicle enlarges rapidly as follicular fluid accumulates
73. What happens during the formation of tertiary follicles during the follicular phase? 8 10 th day after start of ovarian cycle, ovaries usually contain 1 secondary follicle On 10 14 th day, forms large tertiary (Graafian) follicle Tertiary follicle spans cortex bulge on surface of ovary Oocyte projects into antrum (central chamber of follicle) 74. What happens at the end of tertiary follicle development? Increasing LH causes the primary oocyte to Complete meiosis I (just before ovulation) Primary oocyte (meiotic division) secondary oocyte and polar body 75. What happens when a secondary oocyte enters meiosis II? Meiosis stops and is not completed unless fertilization occurs 76. What happens on day 14 of a 28 day cycle? Day 14 (of 28 day cycle), secondary oocyte and surrounding granulosa cells (corona radiata) lose connections with follicular wall (in preparation for ovulation) 77. What occurs during ovulation? 1. Tertiary follicle (ovarian) wall ruptures 2. Secondary oocyte released into pelvic cavity 3. Sticky follicular fluid keeps corona radiata attached to ovary surface Comes in contact with fimbriae, or Fluid currents transfer secondary oocyte to uterine tube 4. Marks end of ovarian follicular phase and start of luteal phase 78. What generally occurs during the luteal phase of the ovarian cycle? List aka for luteal phase. Aka: Postovulatory phase Formation and degeneration of corpus luteum (CL) 79. What does the luteal phase involve? Involves formation and degeneration of corpus luteum (CL) Empty tertiary follicle collapses, ruptured blood vessels leak into antrum corpus hemorrhagicum (bloody body) LH stimulates remaining granulosa cells proliferate corpus luteum (CL, yellow body)
80. What does the corpus luteum (CL) produce? Progesterone = principle ovarian hormone after ovulation Small amount of estrogen (principle hormone before ovulation) 81. What is the primary function of progesterone? What does progesterone stimulate? Primary function is to prepare uterus for pregnancy Stimulates: Development of uterine lining (endometrium) Secretions of uterine glands 82. Describe what happens in the absence of fertilization. CL begins to degenerate 12 days after ovulation Estrogen and progesterone levels fall Fibroblasts invade corpus luteum corpus albicans (white body) Disintegration (involution) of corpus luteum marks end of ovarian cycle FSH new cycle and new follicular phase Another group of primordial follicles form primary follicles 83. Describe the uterine tube. A hollw muscular tube lined with mucosal membrane that produces mucus. The mucosa is surrounded by layers of smooth muscle 84. The oocyte is transported from the infundibulum to the uterine cavity, which normally takes 3 4 days. 85. Secondary oocyte transport involves ciliary movements and peristaltic contractions. 86. Where does fertilization occur and when must it happen? Occurs near boundary between ampulla and isthmus Must happen during first 12 24 hours 87. What is the nutrient supply for the spermatozoa and developing oocyte? Lipids and glycogen
88. What is the function of the uterine wall? Provides for developing embryo (weeks 1 8) and fetus (week 9 through delivery) with: Protection Nutritional support Waste removal 89. List the 3 layers of the uterine wall. 1. Perimetrium 2. Myometrium 3. Endometrium 90. Describe the Perimetrium. Serous membrane that covers outer surface of uterus Continuous with peritoneal lining of abdominopelvic cavity 91. Describe the Myometrium. Thick layers of smooth muscle Longitudinal, circular, oblique layers Provides force needed to move fetus out of uterus and into vagina Arteries Arcuate radial arteries (in myometrium) straight spiral (endometrium) 92. Describe the Endometrium. Thin glandular, vascular layer Lines surface of uterine cavity Supports physiological demands of (potential) fetus Under influence of estrogen Uterine glands, blood vessels, and epithelium change with phases of monthly uterine cycle Has 2 zones 93. What are the 2 zones of the endometrium? 1. Basilar 2. Functional
94. Describe the basilar zone of the uterine wall. Outer zone, adjacent to myometrium Attaches endometrium to myometrium Contains Terminal branches of uterine glands Straight arteries Structure remains constant over time 95. Describe the functional zone of the uterine wall. Closest to uterine cavity; thickest Contains most of uterine glands Blood supply provided by spiral arteries Undergoes cyclical changes in response to sex hormones Degeneration, sloughing menses 96. What is the uterine/endometrial (menstrual) cycle? Repeating series of changes in structure of endometrium that occur in response to the ovarian hormones (E and P) and whose average length is 28 days (range 21 35) 97. What are the 3 phases of the uterine/endometrial cycle and when does each occur? 1. Menses occurs during early follicular phase of ovarian cycle 2. Proliferative phase occurs during later follicular phase of ovarian cycle 3. Secretory phase corresponds to luteal phase of ovarian cycle 98. What does menses mark the beginning of? Marks beginning of uterine cycle (Day 1) 99. Define menses. Degeneration and loss of entire functional zone of endometrium where blood cells and degenerated tissues break away and enter uterine lumen, vagina 100. What causes the degeneration and loss of the entire functional zone of the Endometrium? Caused by constriction of spiral arteries reduced blood flow to endometrium no O2 or nutrients Secretory glands deteriorate Arterial walls rupture
101. What is menstruation? How long does it last? How much blood is lost during menstruation? endometrial sloughing Lasts 1 7 days Lose small amount of blood (35 50 ml) 102. What is dysmenorrheal? What is its cause(s)? Painful menstruation Due to uterine inflammation and contraction (due to prostaglandins) Other conditions of pelvic structures 103. Describe the proliferative phase of the uterine (menstrual) cycle. After menses (Days 8 14) Increase in basilar uterine gland cells Further growth and vascularization restoration of functional zone Occurs at same time as enlargement of primary and secondary follicles in ovary (follicular phase) Phase stimulated and sustained by E from ovarian follicles 104. Describe the secretory phase of the uterine (menstrual) cycle. Begins at ovulation (Day 14) Lasts as long as CL (14 days) Occurs in response to CL P and E Endometrial glands enlarge Arteries elongate and spiral through functional zone Secretory activities peak 12 days after ovulation CL stops producing P and E Glandular activity declines over next 1 2 days Uterine cycle ends (Day 28, 14 days after ovulation) 105. A new menses cycle (day 1) begins with the disintegration of the functional zone followed by menses. 106. When does ovulation occur? Day 14 107. What is menarche? First uterine cycle at puberty (approx age 11 12)
108. What does amenorrhea mean? List the 2 types. Amenorrhea = no menses 2 types: Primary amenorrhea Secondary amenorrhea 109. What is primary amenorrhea? What is it caused by? Failure to initiate menses; no menarche Caused by: Developmental abnormalities (e.g. nonfunctional ovaries, absence of uterus) Endocrine or genetic disorder Malnutrition 110. What is secondary amenorrhea? What is it caused by? Menses interrupted for > 6 months Caused by: Physical stresses (e.g., drastic weight loss, anorexia nervosa, intensive physical training (marathon runners)) Emotional stresses (e.g., severe depression, grief) 111. The female reproductive tract is under the control of the pituitary and the ovaries. 112. The female reproductive tract is more complicated than in males because both ovarian and uterine cycles have to be coordinated. If they are not coordinated, what happens and why? If not coordinated, infertility results: Uterus normal but do not ovulate Ovulate but uterus abnormal 113. Explain the role that the hypothalamus plays in the female reproductive system. GnRH from Hth regulates reproductive function in females (like males) But, GnRH amount and release frequency changes throughout ovarian cycle (constant in males) GnRH FSH and/or LH depending on pulse frequency and amount secreted Change in GnRH controlled by estrogen and progesterone
114. In the female reproductive system, how is the role of GnRH similar to and different than its role in the male reproductive tract? 1. GnRh amount and release frequency varies during ovarian cycle in females, it is constant in males 2. GnRh pulse frequency variable in women, so FSH and LH secretion varies, it is constant in males 3. Similarity: GnRH stimulates FSH secretion and LH synthesis in males and females 115. FSH stimulates the monthly development of monthly development of some primordial follicles into primary follicles. 116. What is the function of FSH females and males? Females promotes egg and follicle development in ovaries Males promotes sperm development in testes (STs) 117. What happens to FSH levels as secondary follicles develop? As secondary follicles develop, FSH decreases due to negative feedback effects of inhibin (produced by granulosa cells) 118. As follicular development /maturation continues it is supported by FSH, estrogen and LH. 119. What two types of cells work together to produce estrogens? Follicle and thecal cells 120. What are the follicle cells around the oocyte in the ovary responsible for? The production of estrogen and inhibin 121. What is the dominant hormone prior to ovulation? Estrogens (E) 122. What happens to the estrogen levels as the tertiary follicle begins forming? Estrogens rise sharply as tertiary follicle begins forming
123. List the physiological effects of estrogen. 1. Stimulates endometrial growth and secretion 2. Maintains accessory glands and organs 3. Establishes/maintains female secondary sex characteristics Body hair distribution, fat deposits 4. Stimulates bone and muscle growth 5. Affects CNS (esp. Hth E inc sex drive) 124. A sudden surge of LH is released in response to high estrogen levels. 125. What does a sudden surge in LH trigger? Sudden surge triggers: Completion of meiosis I by primary oocyte (in tertiary follicle) secondary oocyte Rupture of follicular wall Ovulation (9 hours after LH peak) 126. What does LH promote in females? Ovarian secretion of progesterone 127. What does LH promote in males? Testicular secretion of testosterone 128. By what ovarian structure is progesterone secreted and what is it secreted in response to? Secreted by CL in response to LH peak 129. What is the dominant hormone after ovulation? Progesterone is the dominant hormone after ovulation (as P inc, E dec) 130. What is the primary function of progesterone in female reproduction? To prepare uterus for possible pregnancy
131. What happens to the progesterone levels at and after LH reaches its peak? Increases endometrium functional zone Growth Secretion Blood supply Remains high for 7 days Declines as CL degenerates (when pregnancy doesn t occur) Decreased P and E initiates menses and increasing GnRH stimulates FSH, etc. 132. Inhibin is secreted by follicular cells and inhibits FSH production and secretion (causes a of FSH and possible GnRH in both males and females). 133. What is the relationship between hormones and body temperature? Monthly hormonal fluctuations affect core body temperature Basal body temp lower during follicular phase, when E dominant hormone Decreases basal body temperature (BBT) at ovulation Large increase during luteal phase, when P dominates Use to plan/avoid fertilization 134. What coordinates sexual function? Coordinated by complex neural reflexes 135. In order for the male reproductive system to function successfully, what must occur? Sperm count must be adequate Semen must have correct ph and nutrients Erection and ejaculation must function properly 136. What is impotence? The inability to achieve or maintain an erection 137. In order for the female reproductive system to function successfully, what must occur? Ovarian and uterine cycles must coordinate properly Ovulation and oocyte transport must occur normally Environment of reproductive tract must support: Survival and movement of sperm Fertilization of oocyte Maintenance of pregnancy Embryonic and fetal development
138. What must the environment of the reproductive tract support so that the function of the female reproductive tract is successful? 1. Survival and movement of sperm 2. Fertilization of oocyte 3. Maintenance of pregnancy 4. Embryonic and fetal development 139. List characteristics of menopause. Occurs at age 45 55 Time when ovulation and menstruation cease No primordial follicles left to respond to FSH E and P decrease GnRH, FSH, LH increase Accompanied by variety of physiological effects (p. 1066 1067) 140. List characteristics of male climacteric (andropause) Occurs at age 50 60 Period of declining reproductive function T decreases FSH and LH increase Sperm production continues (into 80s) but sex drive reduced