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Preface to the Fifth Edition	p. xii
How to Use This Book	p. xiii
Acknowledgements	p. xiv
Figure Acknowledgements	p. xv
Sex	p. 1
The Genesis of Two Sexes Depends on Genetic Differences	p. 3
The genetic determinant of sex is on the Y chromosome	p. 3
The two gonads develop from a bipotential precursor through the differential action of SRY in males	p. 5
Primary hermaphrodites have both ovarian and testicular tissues	p. 7
The Differentiation of Two Sexes Depends on the Endocrine Activity of the Fetal Testis	p. 8
The male and female internal genitalia develop from different unipotential precursors through the actions of androgens and MIS	p. 8
The male and female external genitalia develop from a single bipotential precursor through the actions of androgens	p. 8
Secondary hermaphrodites have genitalia that are not of the sex expected from their gonads	p. 8
Pre- and Postnatal Growth of the Gonads is Slow Until Puberty	p. 11
The testes migrate to a scrotal position	p. 11
Testicular growth and activity are important for male development	p. 14
Most ovarian germ cells die before puberty and all of them enter meiosis	p. 14
The ovary is not essential for prepubertal development	p. 15
Summary	p. 15
Key Learning Points	p. 16
Further Reading	p. 16
Gender and Sexuality	p. 17
Gender is a System of Classification Based on Sex	p. 17
Gender Stereotypes and Gender Identities	p. 18
A gender stereotype is the set of beliefs about what it means to be a man and woman in a particular society	p. 19
Gender stereotyping provides a social shorthand for classifying people by sex	p. 19
Gender identity describes the personal concept of 'me as a man or a woman'	p. 19
Gender differences may not be as great as they first appear to be	p. 20
The Origins of Gender	p. 20
Hormones, the Brain and Behavioural Dimorphism	p. 20
In animals hormones condition sex differences in behaviour and brain structure	p. 20
Nonhuman primates show sex differences in behaviour which appear to be influenced by hormonal exposure early in life	p. 21
In humans there may be both sex and gender differences in brain structure but it is difficult to be sure whether there are any direct effects of hormones on the developing brain or on the expression of gender attributes	p. 22
Gender Development May Form Part of Social Learning in Humans	p. 24
Patterns of interaction between babies and those around them emphasize gender differences	p. 24
Gendered behaviour by babies may affect the way that they are treated	p. 25
Summary	p. 26
Gender and Reproduction	p. 26
Sexuality Involves the Erotic	p. 27
Sexuality can be classified by the stimulus of erotic arousal	p. 27
Genetics, brain anatomy, androgens and social learning have all been implicated in the formation of sexualities	p. 28
The relationship between sexuality and gender	p. 29
Summary	p. 30
Key Learning Points	p. 31
Further Reading	p. 31
Reproductive Messengers	p. 33
Hormones Can Act at Variable Distances From the Cells That Produce Them	p. 33
There are Three Main Classes of Hormone	p. 34
Lipids	p. 34
Proteins	p. 37
Monoamines	p. 42
Hormonal Actions Involve Receptors	p. 45
Hormone activity can be regulated by controlling receptor expression	p. 46
Receptor stimulation activates target cell transducer systems	p. 48
The Levels of a Hormone in Its Target Tissues Depend on Its Turnover	p. 48
Blood levels of hormones may fluctuate because their secretion may fluctuate	p. 48
Hormones can be metabolized as they pass round the body	p. 50
Levels of hormones can be affected by the presence of binding proteins	p. 50
Hormones may be metabolized in their target tissues	p. 51
Summary	p. 51
Key Learning Points	p. 52
Further Reading	p. 52
Testicular Function in the Adult	p. 53
The Testis is Divided Into Compartments	p. 53
Spermatogenesis has Three Main Phases	p. 55
Mitotic proliferation increases cell number	p. 55
Meiosis halves the chromosome number and generates genetic diversity	p. 55
Cytodifferentiation packages the chromosomes for delivery	p. 56
Genetic activity ceases as spermatogenesis progresses	p. 56
Spermatogenesis is Highly Organized Both Temporally and Spatially	p. 60
Spermatogenesis proceeds at a constant and characteristic rate for each species	p. 60
Rounds of spermatogenesis are initiated at time intervals that are constant and characteristic for each species	p. 60
The seminiferous epithelium cycles	p. 62
Spermatogenesis in adjacent regions of a seminiferous tubule appears to be phase advanced or retarded	p. 63
The Sertoli cell may control the temporal and spatial organization of spermatogenesis	p. 64
Summary	p. 64
Testicular Endocrine Activity and the Control of Spermatogenesis	p. 64
The testis produces hormones	p. 64
Spermatogenesis is dependent upon endocrine support	p. 66
Summary	p. 67
Key Learning Points	p. 67
Further Reading	p. 68
Adult Ovarian Function	p. 69
Fertility in the Adult Female is Episodic	p. 69
The Adult Ovary Consists of Follicles and Interstitial Tissue	p. 70
The Follicle is the Fundamental Reproductive Element of the Ovary	p. 70
Follicles grow and mature	p. 71
Ovulation	p. 77
The corpus luteum is the postovulatory 'follicle'	p. 78
The Number of Follicles Ovulating Depends on the Balance Between Gonadotrophin Levels and Their Follicular Receptors	p. 80
Follicular Development and the Ovarian Cycle	p. 81
The ovarian cycle is the interval between successive ovulations and comprises follicular and luteal phases	p. 81
The ovarian cycle of the human	p. 82
The ovarian cycles of the cow, pig, sheep and horse have a shorter follicular phase	p. 83
The ovarian cycles of the rat and mouse can have abbreviated follicular and luteal phases	p. 83
The ovarian cycle of the rabbit is reduced to an extended follicular phase	p. 83
Interstitial Glands	p. 84
Summary: the Oestrous and Menstrual Cycles	p. 84
Key Learning Points	p. 86
Further Reading	p. 87
The Regulation of Gonadal Function	p. 88
The Hypothalamic-Pituitary Axis Controls Gonadal Function	p. 89
The pituitary secretes gonadotrophins, prolactin and oxytocin	p. 89
The hypothalamus contains groups of neurons with specific functions	p. 89
The hypothalamus and pituitary have both neural and vascular connections	p. 90
Summary	p. 94
Ovarian Hormones Regulate Gonadotrophin Secretion in Females	p. 94
Oestradiol regulates FSH and LH secretion	p. 95
Progesterone also regulates FSH and LH secretion	p. 95
Inhibin also regulates FSH secretion	p. 96
Steroid hormone and inhibin feedback regulate the menstrual cycle	p. 97
Positive and negative feedback are mediated by the hypothalamus and pituitary	p. 98
Testicular Hormones Regulate Gonadotrophin Secretion in Males	p. 103
Testosterone regulates the pituitary-Leydig cell axis	p. 103
Inhibin regulates the pituitary-seminiferous tubule axis	p. 103
The Hypothalamic-Pituitary-Gonadal Axis May be Sexually Dimorphic	p. 104
Prolactin has Reproductive Functions	p. 105
The hypothalamus controls prolactin secretion	p. 105
Prolactin has diverse functions	p. 107
Hyperprolactinaemia suppresses fertility	p. 108
The Environment Influences Reproduction	p. 108
Daylight affects fertility	p. 109
Coitus affects fertility in some species	p. 111
Social interactions and stress can affect fertility	p. 111
Summary	p. 113
Key Learning Points	p. 115
Further Reading	p. 118
Puberty and the Maturation of the Hypothalamic-Pituitary-Gonadal Axis	p. 119
Puberty	p. 119
Growth hormone and sex steroids underlie the physical changes during puberty	p. 120
Gonadal activation underlies the development of secondary sexual characteristics	p. 120
Similar pubertal changes occur in other mammals	p. 121
There is a Distinctive Pattern of Hormonal Changes at Puberty	p. 121
Activation of Pulsatile Hypothalamic GnRH Secretion is a Key Event in the Onset of Puberty	p. 124
The gonadostat hypothesis emphasizes maturational changes in steroid feedback mechanisms	p. 125
Activation of hypothalamic GnRH secretion is the driving force behind pubertal development	p. 126
The Timing of Puberty is Linked to the Attainment of a Critical Body Weight	p. 128
There is a secular trend towards earlier puberty that may reflect the influence of environmental factors	p. 128
Cns Pathology May be Associated with Advanced or Delayed Puberty	p. 130
Key Learning Points	p. 131
Further Reading	p. 132
Actions of Steroid Hormones in the Adult	p. 133
Androgens Regulate the Functional Activity of the Male Reproductive System	p. 134
Oestrogens and Progestagens Cyclically Regulate the Functional Activity of the Female Reproductive System	p. 134
Oestrogen and progesterone affect gamete transport by actions on the oviduct (Fallopian tube)	p. 135
Oestrogen and progesterone cause cyclic changes in the uterus to support gamete transport and implantation	p. 136
The properties of the cervix show steroid-dependent changes during the cycle that affect gamete transport	p. 138
Oestrogen and progesterone cause cyclic structural changes in the vagina	p. 139
Other tissues	p. 139
Hormones Regulate Sexual Behaviour in Many Species	p. 140
Masculine sexual behaviour	p. 141
Feminine sexual behaviour	p. 143
Summary	p. 147
Sex Steroids Act in the Brain to Control Sexual Behaviour	p. 148
Testosterone or its metabolites act primarily within the medial preoptic area to control masculine sexual behaviour	p. 148
Oestradiol and progesterone act primarily within the ventromedial hypothalamus to control sexual behaviour in female nonprimates	p. 150
How do hormones affect behaviour?	p. 150
Summary	p. 151
Key Learning Points	p. 151
Further Reading	p. 152
Coitus and Fertilization	p. 153
The Transport of Spermatozoa to the Oocyte is Hazardous and Most Do Not Arrive	p. 153
Spermatozoa require a period of epididymal maturation	p. 154
Semen is made up of spermatozoa and seminal plasma	p. 155
Coition involves genital reflexes and sexual responses	p. 156
Semen is deposited in the vagina, cervix or uterus depending on the species	p. 160
Gametes are Transported Through the Female Genital Tract	p. 160
Spermatozoa are transported largely by their own activity	p. 160
Oocyte transport depends on the activity of the oviduct	p. 161
Fertilization is a Protracted Process Taking many Hours for Completion	p. 161
Spermatozoa gain their full fertilizing capacity in the female tract: capacitation	p. 161
The acrosome reaction is essential if spermatozoa are to bind to and penetrate the zona pellucida	p. 162
Gamete fusion may involve integrins and stimulates Ca[superscript 2+] release in the oocyte	p. 165
Oocytes can be activated in the absence of a spermatozoon (parthenogenesis) but cannot develop to term	p. 168
Reproductive cloning	p. 169
Summary	p. 170
Key Learning Points	p. 170
Further Reading	p. 171
Implantation and the Establishment of the Placenta	p. 173
The Conceptus Must Convert the Maternal Reproductive Pattern From Cyclic to Pregnant	p. 173
The Preimplantation Conceptus	p. 174
The control of development switches from mother to conceptus soon after fertilization	p. 174
Early differentiative events are mostly concerned with establishing extra-embryonic supporting tissues for the future embryo and fetus	p. 175
The Timing and Spatial Organization of the Implantation Events Affect the Form that the Placenta will Ultimately Take	p. 177
Invasive implantation occurs in the human, all primates except lemurs and lorises, the dog, cat, mouse and rabbit	p. 179
Noninvasive implantation occurs in the pig, sheep, cow and horse	p. 180
The Ovary, Uterus and Conceptus Engage in Complex Conversations to Control the Process of Implantation	p. 181
Implantation depends on ovarian steroid support	p. 181
The molecular language used by the communicating endometrium and conceptus at attachment and implantation is being decoded	p. 183
Summary	p. 184
The Change From Histiotrophic to Haemotrophic Support	p. 185
The extra-embryonic membranes give rise to the fetal membranes	p. 185
The placental interface is organized to facilitate exchange between maternal and fetal circulations	p. 185
Blood flow in the placenta	p. 189
Summary	p. 191
Key Learning Points	p. 192
Further Reading	p. 192
Maternal Recognition and Support of Pregnancy	p. 194
Maternal Recognition of Pregnancy Requires that Luteal Life be Prolonged	p. 194
Chorionic gonadotrophin prolongs luteal life in primates	p. 194
Suppression of luteolytic activity prolongs luteal life in large domestic animals	p. 195
Pregnancy Hormones are Required for the Support of Pregnancy	p. 196
The human conceptus synthesizes steroid hormones	p. 197
Different strategies achieve the endocrine support of pregnancy in other species	p. 200
Summary	p. 201
Key Learning Points	p. 201
Further Reading	p. 202
The Fetus and its Preparations for Birth	p. 203
Both Fetal and Maternal Factors Determine Fetal Growth and Well-being During Pregnancy	p. 203
Fetal Metabolism Depends Critically Upon Placental Transport of Essential Nutrients	p. 205
Oxygen and carbon dioxide	p. 205
Glucose and carbohydrate	p. 207
Amino acids and urea	p. 208
Fatty acids	p. 208
Water and electrolytes	p. 209
Iron	p. 209
Calcium	p. 209
Vitamins	p. 209
Bilirubin	p. 210
Amniotic Fluid is Derived from Maternal and Fetal Fluids	p. 211
Fetal Systems Develop and Mature in Preparation for Postnatal Life	p. 212
The cardiovascular system	p. 212
The respiratory system	p. 213
The gastrointestinal system	p. 215
The renal system	p. 215
The nervous system	p. 215
Summary	p. 216
Fetal and Neonatal Neuroendocrine Systems Co-Ordinate Many Aspects of Fetal Development and Preparations for Birth	p. 216
The anterior pituitary	p. 216
The thyroid gland	p. 217
The parathyroid glands and calcium-regulating hormones	p. 217
Glucagon and insulin	p. 217
The adrenal gland	p. 217
The Fetus Survives Maternal Immune Rejection Through Several Mechanisms	p. 218
Antigenicity of the conceptus	p. 218
Protective immunological barrier	p. 218
Maternal immune responsiveness	p. 219
Summary	p. 220
Summary	p. 220
Key Learning Points	p. 220
Further Reading	p. 222
Parturition, 223
The Myometrium and Cervix are Tissues Critically Involved at Parturition	p. 223
Contractility of the myometrium depends upon changes in intracellular calcium regulated by prostaglandins and oxytocin	p. 224
Prostaglandins can induce softening of the uterine cervix but nitric oxide may also be involved physiologically	p. 225
Prostaglandin, Oxytocin and Nitric Oxide Actions at Parturition are Regulated by Steroids	p. 225
Prostaglandin and nitric oxide activities are regulated by changing oestradiol/progesterone ratios	p. 225
Oxytocin is released from the posterior pituitary by stimulation of the uterine cervix and by myometrial contractions at parturition	p. 226
Summary	p. 227
Adrenal Glucocorticoids Exert Major Controls on the Timing of Onset of Parturition	p. 227
Parturition in goats follows luteal regression induced by fetal glucocorticoid-induced increases in PGF[subscript 2[alpha]]	p. 227
Fetal glucocorticoids alter placental steroid and PGF[subscript 2[alpha]] secretion to induce parturition in sheep	p. 227
The endocrine mechanisms causing parturition in women are poorly understood	p. 228
Summary	p. 229
Relaxin is a Pregnancy Hormone that May Influence Parturition	p. 229
The corpus luteum is a major source of relaxin	p. 229
Relaxin influences cervical softening and mammary development in nonprimate species	p. 229
Labour Has Three Stages	p. 230
Fetal Monitoring Can Reveal Fetal Distress During Labour and Indicate the Need for Caesarian Section	p. 231
Hiv Can be Transmitted During Pregnancy, at Parturition and in Breast Milk	p. 231
Summary	p. 232
Key Learning Points	p. 232
Further Reading	p. 232
Lactation and Maternal Behaviour	p. 234
Lactation Provides A Primary Source of Nutrition for the New-Born	p. 234
The breast develops during pregnancy under the influence of several hormones	p. 235
Breast milk is a rich source of nutrients and energy	p. 237
A changing oestrogen/progesterone ratio and prolactin initiate and maintain milk secretion	p. 238
Summary	p. 238
The Milk Ejection Reflex Enables A Suckling Infant to Remove Milk from the Breast	p. 239
The MER is a neurosecretory mechanism engaged by suckling	p. 239
Babies express milk from the nipple or teat during suckling	p. 240
Summary	p. 241
Fertility is Reduced During Lactation	p. 242
Cessation of Lactation May be Achieved Pharmacologically or Naturally	p. 242
Lactation can be suppressed by dopamine receptor agonists	p. 242
The breast involutes when lactation ceases	p. 242
Maternal Behaviour Appears Promptly Around Parturition and is Critical for Survival of the New-Born	p. 242
Patterns of maternal behaviour change with time and vary with the state of maturity of the new-born	p. 243
In nonprimates both exposure to young and sex hormones influence maternal behaviour	p. 243
In primates, mother-infant interaction changes dynamically	p. 246
In humans, attachment behaviour secures a bond between mother and infant	p. 248
Summary	p. 248
Key Learning Points	p. 249
Further Reading	p. 249
Fertility	p. 251
Fertility, Fecundibility and Fecundity	p. 252
Age, Senescence and Reproductive Capacity	p. 252
Women	p. 253
Men	p. 254
Social Constraints on Fertility	p. 255
Artificial Control of Fertility	p. 255
Sterilization	p. 256
Contraception	p. 256
Abortion	p. 264
Risks versus effectiveness	p. 264
Infertility and Subfertility	p. 265
Disorders of the female tract	p. 265
Disorders of ovulation	p. 266
Oligospermia	p. 268
Spontaneous pregnancy loss	p. 269
Summary	p. 271
Reproduction, Sexuality, Ethics and the Law	p. 271
Conclusion	p. 272
Key Learning Points	p. 273
Further Reading	p. 273
Index	p. 275
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