chapter 10

qualities of hormones (vs. neurotransmitters)

wolffian ducts

precursors to male reproductive organs, develop into vas deferens and seminal vescicles, at early stage of prenatal development both male and female have set of M and W ducts

mullerian ducts

precursors to females oviducts, uterus and upper vagina

at early stage of prenatal development, both female and male have set of M and W ducts

SRY gene

Y chromosome includes SRY gene, causes primitive gonads to develop into testes, developing testes then produce androgens, feales lack SRY gene and gonads develop into ovaries

organizing effects of sex steroids

occurs at sensitive periods of development (before birth and at puberty), determine whether brain and body will develop male or female characteristics

activating effects of sex steroids

occur at any time of life and temporarily activates a particular response, ex - pregnancy, menstruation

distinction between the effects of sex steroids

not absolute, hormones early in life can exert temporary effects

during puberty, hormones can also induce long lasting structural changes

ways sex steroids exert their effects

contain 4 rings and exert in 3 ways

1. binding to membrane receptors like neurotransmitters

2. entering cells and activating certain kinds of proteins in cytoplasm

3. binding to chromosomes where they activate or inactivate certain genes

androgens

group of primarily male hormones, testosterone is most widely known

estrogen

most common is estradiol, progesterone, prepares uterus for implantation of fertilized ovum, promotes maintenance of pregnancy

do men have estrogen?

higher in women, but men have it too

do women have testosterone?

higher in men, but women have it too

how does sexual differentiation start?

begins with chromosomes, during early stage both male and female have set of m and w ducts

which sex steroid "completes" sexual differentiation?

testosterone - depends mostly on level during sensitive period, human sensitive period for genital formation occurs during first semester of pregnancy

absence of testosterone menas fetus will develop

female

presence of testosterone means fetus will develop

male

ways in which the hypothalamus is different between the sexes - medial preoptic area

more dendritic spines and synapses in males, caused by testosterone and estradiol increase production of prostaglandin e2

ways in which the hypothalamus is different between the sexes - ventromedial nucleus

more widely branched dendrites in males, estradiol activates p12 which increases glutamate release

ways in which the hypothalamus is different between the sexes - arcruat e nucleus and anteroventral periventricular nucleus

more dendritic spines and synapses in females, estradiol increases GABA production which acts on astrocytes to decrease dendritic branching

changes in emotional perception after administration of testosterone (for women)

many feel disconnect or conflict with being female

congenital adrenal hyperplasia (CAH) - intersex

most common cause is overdevelopment of adrenal glands from birth, caused by genetic defect, cortisol production leads to overstimulation of adrenal glands (leads to extra testosterone production)

congenital adrenal hyperplasia (CAH)

the overdevelopment of the adrenal glands from birth, brains of genetic females with CAH were exposed to higher levels of testosterone during prenatal/early postnatal life, during adolescence CAH girls showed interests in between those of typical males and females

androgen insensitivity

condition in which individuals with an XY chromosome pattern have the genital appearance of a female or smaller than average penis, many individuals develop and identify as female and don't realize they have insensitivity until puberty, lack androgen receptor that enables is to activate genes in a cell's nucleus

female rats face sex bias too