Reproductive Behavior Chapter 9 Reproductive Behavior This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network preparation of any derivative work, including the extraction, in whole or in part, of any images any rental, lease or lending of the program. Copyright © 2008 Pearson Allyn & Bacon Inc.

Chapter 9 Outline Sexual Development Hormonal Control of Sexual Behavior Neural Control of Sexual Behavior Parental Behavior Copyright © 2008 Pearson Allyn & Bacon Inc.

Sexually _________________behavior Sexual Development Sexually _________________behavior A behavior that has different forms or that occurs with different probabilities or under different circumstances in _____________________. Courting behavior Mating behavior Parental behavior Aggression Copyright © 2008 Pearson Allyn & Bacon Inc.

Sexual Development Sexual development ______________: Sex chromosome: A mature reproductive cell; a sperm or ovum. __________: contains one member of a pair of ___ chromosomes Sex chromosome: The X and Y chromosomes, which determine an organism’s gender. Normally, females are XX and males are XY. Copyright © 2008 Pearson Allyn & Bacon Inc.

Gender is determined by the ___ chromosome in the sperm. Copyright © 2008 Pearson Allyn & Bacon Inc.

Development of the sex organs __________ Sexual Development Development of the sex organs __________ An ovary or testis. ____ The gene of the Y chromosome whose produce instructs the undifferentiated fetal gonads to develop into testes. Copyright © 2008 Pearson Allyn & Bacon Inc.

Natures impulse is to build a female body unless instructed to do otherwise. Exposure to sex hormones _________________ is responsible for sexual dimorphism. The immature gonad is capable of becoming female (ovary) or male (testes). Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

_____________effect (of hormone) Sexual Development Development of the sex organs: hormomes have both organizational and activational effects _____________effect (of hormone) The effect of a hormone on tissue differentiation and development. These effects are ___________. ______________effect (of hormone) The effect of a hormone that occurs in the fully developed organism; may depend on the organism’s prior exposure to the organizational effects of hormones. Copyright © 2008 Pearson Allyn & Bacon Inc.

The immature gonad has both a Müllerian and Wolffian system Sexual Development Internal sex organs: The immature gonad has both a Müllerian and Wolffian system _______________system The embryonic precursors of the female internal sex organs. ________________system The embryonic precursors of the male internal sex organs. Copyright © 2008 Pearson Allyn & Bacon Inc.

Anti-Müllerian hormone Sexual Development Internal sex organs Anti-Müllerian hormone A peptide secreted by the fetal testes that inhibits the development of the Müllerian system, which would otherwise become the ________________________. Defeminizing effect An effect of a hormone present early in development that reduces or prevents the later development of anatomical or behavioral characteristics typical of females. Copyright © 2008 Pearson Allyn & Bacon Inc.

_______________effect Sexual Development Internal sex organs _____________ A male sex steroid hormone. Testosterone is the principal mammalian androgen. _______________effect An effect of a hormone present early in development that promotes the later development of anatomical or behavioral characteristics typical of males. _______________ The principal androgen found in males. Copyright © 2008 Pearson Allyn & Bacon Inc.

____________________________ Sexual Development Internal Sex Organs Dihydrotestosterone An androgen, produced from testosterone through the action of the enzyme 5 reductase. ____________________________ A condition caused by a congenital lack of functioning androgen receptors; in a person with XY sex chromosomes, causes development of a female with testes but no internal sex organs. The external genitalia are _______________________________________. Copyright © 2008 Pearson Allyn & Bacon Inc.

Persistent Müllerian duct syndrome Sexual Development Internal sex organs Persistent Müllerian duct syndrome A condition caused by a congenital lack of anti-Müllerian hormone or receptors for this hormone; in a male, causes development of ________________________________________. The presence of the female anatomy disrupts the functioning of the male anatomy. ___________________ The presence of only one sex chromosome (X0); characterized by lack of ovaries but otherwise normal female sex organs and genitalia. (Usually the result of a defective sperm.) Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

_______________________________ Sexual Development _______________: The onset of puberty is governed by the hypothalamus by the initiation of the secretion of gonadotropin-releasing hormone. _______________________________ A hypothalamic hormone that stimulates the anterior pituitary gland to secrete gonadotropic hormone. ______________________hormone A hormone of the anterior pituitary gland that has a stimulating effect on cells of the gonads. Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

_______________________ Sexual Development Sexual maturation (2 gonadotropic hormones are secreted by the pituitary) _______________________ The hormone of the anterior pituitary gland that causes development of an ovarian follicle and the maturation of it as an ovum. __________________ A hormone of the anterior pituitary gland that causes ovulation and development of the ovarian follicle into a corpus luteum. In males these same hormones cause the ____________________________________________ Copyright © 2008 Pearson Allyn & Bacon Inc.

Sexual maturation (Female) _______________ Sexual Development Sexual maturation (Female) _______________ The principal estrogen of many mammals, including humans. ________________ A class of sex hormones that causes maturation of the female genitalia, growth of breast tissue, and development of other physical features characteristic of females. Copyright © 2008 Pearson Allyn & Bacon Inc.

Sexual maturation (Male) ____________________ Sexual Development Sexual maturation (Male) ____________________ The principal androgen of many mammals, including humans. ______________ A class of sex hormones that causes maturation of the male genitalia, growth of facial and body hair, lowering of the voice, muscle development, and development of other physical features characteristic of males. Copyright © 2008 Pearson Allyn & Bacon Inc.

Hormonal Control of Sexual Behavior Hormonal control of female reproductive cycles __________________ The female reproductive cycle of most primates, including humans, characterized by growth of the lining of the uterus, ovulation, development of a corpus luteum, and (if pregnancy does not occur) menstruation. Copyright © 2008 Pearson Allyn & Bacon Inc.

Hormonal Control of Sexual Behavior Hormonal control of female reproductive cycles _________________ The female reproductive cycle of mammals other than primates. ___________________ A cluster of epithelial cells surrounding an oocyte which develops into an ovum. Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

Hormonal Control of Sexual Behavior Hormonal control of female reproductive cycles Menstrual or estrus cycles ____________________ A cluster of cells that develops from the ovarian follicle after ovulation; secretes estradiol and progesterone. ______________________ A steroid hormone produced by the ovary that maintains the endometrial lining of the uterus during the later part of the menstrual cycle and during pregnancy. Copyright © 2008 Pearson Allyn & Bacon Inc.

The surge in LH causes _____________. FSH stimulates the growth of an ovarian follicle (a sphere of cells surrounding each ovum). The follicle secretes estradoil which in turn causes the pituitary to secrete LH. The surge in LH causes _____________. Following ovulation the ruptured follicle becomes the corpus luteum which secretes progesterone and estradiol which promote pregnancy. Copyright © 2008 Pearson Allyn & Bacon Inc.

Hormonal Control of Sexual Behavior of Laboratory Animals Males Intromission, pelvic thrusting, ejaculation ________________ A period of time after a particular action (for example, an ejaculation by a male) during which that action cannot occur again. ___________________ The restorative effect of introducing a new female sex partner to a male that has apparently become “exhausted” by sexual activity. Copyright © 2008 Pearson Allyn & Bacon Inc.

Hormonal Control of Sexual Behavior of Laboratory Animals Females ______________ A sexual spinal reflex seen in many four-legged animals. Female mammals; arching of the back in response to approach of a male or to the touch of the flanks, which elevates the hindquarters. In the absence of this reflex intromission is no possible. No recreational (non-reproductive) mating behavior. Copyright © 2008 Pearson Allyn & Bacon Inc.

Castrated at birth Copyright © 2008 Pearson Allyn & Bacon Inc.

____________________ Organizational Effects of Androgens on Behavior: Masculinization and Defeminization Effects of pheromones __________________ A chemical released by one animal that affects the behavior or physiology of another animal; usually smelled or tasted. ____________________ The slowing and eventual cessation of estrous cycles in groups of female animals that are housed together; caused by a pheromone in the animal’s urine. Copyright © 2008 Pearson Allyn & Bacon Inc.

____________________ Organizational Effects of Androgens on Behavior: Masculinization and Defeminization Effects of pheromones ____________________ The synchronization of the menstrual or estrous cycle of a group of females, which occurs only in the presence of a pheromone in a male’s urine. ________________________ The earlier onset of puberty seen in female animals that are housed with males; caused by a pheromone in the male’s urine. Copyright © 2008 Pearson Allyn & Bacon Inc.

_________________________ Organizational Effects of Androgens on Behavior: Masculinization and Defeminization Effects of Pheromones ___________________ Termination of pregnancy caused by the odor of a pheromone in the urine of a male other than the one that impregnated the female. _________________________ A sensory organ that detects the presence of certain chemicals, especially when a liquid is actively sniffed; mediates the effects of some pheromones. Copyright © 2008 Pearson Allyn & Bacon Inc.

____________________ Organizational Effects of Androgens on Behavior: Masculinization and Defeminization Effects of pheromones ____________________ A neural structure located in the main olfactory bulb that receives information from the vomeronasal organ. Copyright © 2008 Pearson Allyn & Bacon Inc.

Menstrual synchronization Essence of Genieve Pheromones in humans Menstrual synchronization Essence of Genieve May function to ____________________ Androstadienone (AND) in male sweat induces alertness and _________________in women, but not in men. Could play a role in bonding, mate attraction and mate recognition. Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

Female initiation promotes conception Copyright © 2008 Pearson Allyn & Bacon Inc.

Neural Control of Sexual Behavior Prenatal androgenization of genetic females _______________________________ (CAH) A condition characterized by hypersecretion of androgens by the adrenal gland; in females, causes masculinization of the external genitalia. Increase in bisexual and homosexual orientation. Increase play with male-typical toys. Copyright © 2008 Pearson Allyn & Bacon Inc.

Sexual Orientation Sexual orientation refers to a person’s preference for emotional and sexual relationships with individuals of the same sex, other sex and/or either sex; an enduring sexual attraction toward members of either one’s own gender (homosexual orientation) or the other gender (heterosexual orientation) Homosexual Bisexual Heterosexual Revision 2006 PSB

Sexual Preference About 4% of the adult population is homosexual – sexual behavior is directed towards members of one’s own gender. Neuronal factors: LeVay (1991) found that one region of the hypothalamus was two times larger in hetersexual males compared to that for homosexual males. In male monkeys the surgical destruction of these cells reduced the monkeys interest in females, but did not reduce _____________. Revision 2006 PSB

Sexual Motivation Origins of Homosexuality Identical twins have highest concordance (similarity) rates for sexual orientation compared to fraternal twins and adoptive siblings. Same pattern exists for males and females. This suggests that sexual orientation is influenced by genes. Figure 8.8 from: Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall. Sources: Bailly, J. M., & Pillard, R. C. (1991). A genetic study of male sexual orientation. Archives of General Psychiatry, 48, 1089-1096. Bailly, J. M., Pillard, R. C., Neale, M. C., & Agyei, Y. (1993). Heritable factors influence sexual orientation in women. Archives of General Psychiatry, 50, 217-223. Revision 2006 PSB

Bailey & Pillard (1991; 1992) Male homosexuality concordance rates: 52% identical twin 22% fraternal twin 11% adopted brother Female homosexuality concordance rates: 48% identical twin 16% fraternal twin 6% adopted sister Revision 2006 PSB

Origins of Sexual Orientation Homosexuality is more likely to be based on biological factors like differing brain centers, genetics, parental hormone exposure, than _________________________________. OBJECTIVE 15| Discuss the research on environmental and biological influences on sexual orientation. Cynthia Johnson/ Time magazine Homosexual parents Revision 2006 PSB

The Homosexual Man’s Brain The size of the anterior hypothalamus is smaller (LeVay, 1991) and anterior commissure is larger (Allen & Gorski, 1992) in homosexual men. Anterior Commissure http://www.msu.edu Anterior Hypothalamus Revision 2006 PSB

Hormones & Sexual Orientation Prenatal hormones affect sexual orientation during _______________ of fetal development. Animals: Testosterone exposure to fetus results in females (sheep) showing homosexual behavior. Humans: Female hormone exposure to male or female fetus (human) results in attraction to males. Heterosexual male Homosexual Heterosexual female Revision 2006 PSB

Sexual Orientation Recent data suggests that male homosexuality is more common among the male relatives of the men’s _________ side of the family. The gene for sexual orientation is located on the x chromosome – the only chromosome inherited exclusively from one’s __________. Area Xq28 is believe to most strongly influence sexual orientation. Revision 2006 PSB

Changing Attitudes Revision 2006 PSB

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Neural Control of Sexual Behavior Males ___________________ (MPA) An area of cell bodies just rostral to the hypothalamus; plays an essential role in male sexual behavior. Copyright © 2008 Pearson Allyn & Bacon Inc.

Neural Control of Sexual Behavior Males Sexually dimorphic nucleus (SDN) A nucleus in the preoptic area that is much larger in males than in females; first observed in rats; plays a role in male sexual behavior. The size of this nucleus appears to depend on ________________________________________. Copyright © 2008 Pearson Allyn & Bacon Inc.

Neural Control of Sexual Behavior Males Nucleus paragigantocellularis (PGi) A nucleus of the medulla that receives input from the medial preoptic area and contains neurons whose axons form synapses with motor neurons in the spinal cord that participate in sexual reflexes in males. The PGi inhibits sexual reflexes by releasing serotonin on spinal nuclei. The MPA pathway must act to suppress PGi inhibition for sexual reflexes to occur. SSRI drugs emulate PGi inhibition and depress ________________. Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

Neural Control of Sexual Behavior Females ____________________________________(VMH) A large nucleus of the hypothalamus located near the walls of the third ventricle; plays an essential role in female sexual behavior. Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

Pair bonding Increase levels of vasopressin and oxytocin are observed in_____________, relative to polygynous ones, and injections of vasopressin can transform polygynous rodents into _____________pair bonding. Biologically fitness is determined by procreation, and parental behavior is critical for reproductive success. Maternal behavior is established by a hormonal sequence associated with reproduction. Copyright © 2008 Pearson Allyn & Bacon Inc.

Copyright © 2008 Pearson Allyn & Bacon Inc.

Virgin females injected with hormones that duplicates this sequence will rapidly begin to display maternal care for pups. Pair bonding between mother and offspring appear to involve ___________________. fMRI studies show that when mothers are shown photos of their infants that brain centers that contain receptor sites for vasopressin and oxytocin are activated, as well as brain regions involved in ________________. Copyright © 2008 Pearson Allyn & Bacon Inc.

Male and female behaviors are not simply the result of socialization. Summary Male and female behaviors are not simply the result of socialization. The case of Brenda described by Carlson suggests that the infant’s brain was masculinized by early exposure to androgens and Brenda was unable to adjust to the female body and role expectations that had been surgically and chemically constructed for her. Copyright © 2008 Pearson Allyn & Bacon Inc.