Unit 3 Sex Hormone o Chemical secreted by an endocrine gland o Conveyed by the blood to other organs whose activities it influences o Many hormones have more than one target Hormone Classes o Sex hormones are in the Steroid Class o Steroid Class Sex Hormones o Two Classes Testosterone Androgens Estrogens o Activate Sex Limited Genes Primary estrogen is estradiol Effects are much stronger in one sex than the other Androgens stronger in males estrogens stronger in females o Organizing and Activating Effects Organizing Occurs way before birth Determine whether or not the brain and body will develop male or female characteristics Activating Occur after birth like during puberty Chromosomes o Female XX o Male XY SRYG Fetal Development Found on the Y chromosome Causes primitive sex organs to develop into testes o Testes begin to produce testosterone o Both males and females have sets of Mullerian Ducts MIH Y chromosome o Degradation of these ducts o For women develop into uterus and upper vagina Wolffian Ducts Y chromosome Differentiate into Seminal Vesicles and the Vas Deferens For women these ducts degenerate Also have primitive sex organs o All this occurs in Month 3 4 In females these develop into ovaries Male development Only occurs with a high level of testosterone Female sex is not the o Also see effects on the brain as a result of these hormones Hypothalamus Sexually Dimorphic Nucleus o Larger in males than females o Contributes to male sexual behavior Develops cyclical pattern of firing important for menstruation later on Hormones have functions other than sex o Testosterone May decrease pain and anxiety Increase memory o Estrogens Hormone Functions related to sex o Testosterone o Estradiol Increased sexual arousal Increase dendritic branching in the hippocampus High levels pre ovulation increases arousal o Oxytocin indirect Pair bonding Social behaviors Released during orgasms in both sexes Stimulates contractions when a women is going into labor Causes mammary glands to produce breast milk Only hormone important for parental behaviors Variations in Sexual Development and Orientation Some amphibians have the ability to change sex if one sex is scarce in order to reproduce Some individuals may be born with external genitalia that are somewhere between male and female genitalia o These people are referred to as Inter sex Individuals A long time ago people would attempt to remove the male genitalia to fix the problem Now best advice is to just wait until the child is old enough to tell the parents which sex it is o CAH o Androgen Insensitivity Insensitive to all androgens Leads to excessive testosterone secretion leading to a somewhat external male appearance Have an XY chromosome pair but have a complete female identity Will have the external genitalia of a female But have internal testes instead of uterus o Therefore infertile Develop breasts during puberty but do not menstruate Gender Most people acquire a gender identity that matches their external sexual appearance Gender identity is a human characteristic Based on gender roles in the community o Hormones are a big part of this process Sexual Orientation Homosexuality and Heterosexuality both exist in nature Most of what we know about homosexuals has been done about men Genetic Study Results o If you are a monozygotic twin of a gay male you have about a 30 chance of being gay yourself 50 in old study 10 in new study split the difference o If you are a dizygotic twin to a gay male the concordance rate is about 14 o For females the numbers are about the same but a little lower Neuroanatomical Study Results o Do see hemispheric differentiation In heterosexual males right hemisphere is larger than females and homosexual males has more neuronal connections in heterosexual males as opposed to o Right Amygdala heterosexual females and homosexual males o Anterior Commissure heterosexual males is larger in heterosexual females and homosexual males than in o SCN is larger and more elongated in heterosexual females and homosexual males than heterosexual males o Interstitial Nucleus 3 heterosexual females and homosexual males in hypothalamus is larger in heterosexual males than in Hormonal Study Results o Follows the same pattern with heterosexual males on one side and heterosexual females and homosexual males on the other side Myths o Stressful maternal pregnancy increases likelihood of homosexuality Testosterone is dampened when stressed o More likely to be born a gay male if one has an older brother Stress on developing fetus from antigens created by previous pregnancy Emotion James Lang Theory of Emotion o We re actually afraid because we re running not because the axe murderer has presented himself as a danger to us o I m running this must be happening okay I m afraid o Some evidence for it Used individuals with a complete sympathetic activation failure therefore cannot feel emotions except for very brief moments of anger More left hemisphere activity if someone is happy or angry More right hemisphere activity if someone is afraid or disgusted Most vigorous behaviors Fight or Flight o Attack o Escape o Corresponding negative emotions anger fight and fear flight Parts of the Brain important for emotion Insula Cortex Disgust only emotion localized to one area Limbic System Emotional center Amygdala in temporal lobe Fight or Flight Attack Behaviors Anger Emotion Monozygotic resemble each other more closely in relation to violent behaviors compared to dizygotic Adopted children appear to mirror their biological parents violent behaviors more than their adopted parents Interaction with environment o Older you get more likely to choose friends with similar violence behaviors o If you have a particular genetic form and a horrible horrible horrible horrible HORRIBLE childhood you will more likely be violent as an adult No gene for violence TIP o Lay down if you feel angry a lot more difficult to feel aggressive in a vulnerable position Real but weak correlation between testosterone and depression o Men fight more than women arrested for more violent crimes o 15 25 are the worst Testosterone levels are at its highest Chance to become angry more easily if already made angry within the past 20 Brain Areas Amygdala o Part of the limbic system emotion In temporal lobe o Priming aggressive behaviors minutes o activation will cause extreme anger Disorders Intermittent Explosive Disorder o Activation of amygdala causes Rabies Clover Buccy