Psych 2210 1st Edition Lecture 13 Outline of Last Lecture I. Experimental Techniques: Causal MeasuresII. The Sexual BrainIII. Chromosomal and Hormonal FactorsOutline of Current Lecture I. Structural Sexual DimorphismsII. Behavioral Sexual DimorphismsIII. Fetal Hormones and Sexual OrientationIV. Male ProcessV. Steps in Female PhenotypeVI. Clinical cases Current LectureI. Structural Sexual Dimorphismsa. Differences in brain regions between males and femalesi. Provided by organizational effects of prenatal hormonesb. Sexually dimorphic nucleus of the POA (SDN-POA)i. Larger in male ratsc. Lesions in this area disrupt ovulatory and copulatory behaviorsII. Behavioral Sexual Dimorphismsa. Male vs. female rats have stereotypical mating behaviorsb. Tend to mount femalesc. Female arches back and accepts male (iorodosis) d. Determined by prenatal hormonesIII. Fetal Hormones and Sexual Orientationa. Theories about sexual orientationThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.i. Nurture: result of social experiences during childhoodii. Freudian view: “distant father”, over-attachment, identification with motheriii. Social constructivism: sexual orientation is learned, influenced by societal norms, if a child looks male and is raised like a male then that child will inevitably develop a male sexual identityiv. Implications: baby as sexually neutral at birth, homosexuality as result of improper interactions with parents or faulty learning v. Evidence: no evidence for Freudian views, children of lesbian parents generally heterosexual despite prediction that orientation is learned. vi. Nature: biology, process during developmentvii. Working hypothesis: sexual orientation is a sexually differentiated behavioral feature influenced by the prenatal hormonal environmentviii. Predictions: low prenatal testosterone: attraction to males, high prenatal testosterone: attraction to femalesix. Genital tubercle: can form external male or female structuresx. Wolffian ducts: can form male internal organsxi. Mullerian ducts: can form female internal organsIV. Male processa. SRY gene: sex determining region on the y chromosome, turns on b. Development of testes: develops from gonad, caused by SRY genec. Testosterone production: produced by testes, directs rest of sexual differentiationd. Masculinization: testosterone promotes the development of the Wolfian systeme. Defeminization: anti-mullerianf. Testosterone also masculinizes other structures (the prostate gland, scrotum, andpenis) g. 5-reductasei. If an enzyme that converts testosterone into the more powerful dihyrotestosterone (DHT)ii. Necessary to form external male genitalia V. Steps in Female Phenotypea. SRY gene: not present in XXb. Ovaries: develop from gonad if no SRY gene presentc. No testosterone present: rest of differentiationd. De-masculinization: wolfian system atrophies, since no testosterone presente. Feminization: mullerian system develops since no anti-mullerian hormones are presentVI. Clinical Casesa. Congenital adrenal hyperplasia (CAH) i. Adrenal glands provide excessive adrenal hormones (androgens) prenatally b. XX fetus: exposed to androgens before