Exam 3 Fundamentals of Human Reproduction Chapter 1 Reproductive System Anatomy Sexual Differentiation Prenatal in utero development of the male and female reproductive structures o MALE DIFFERENTIATION gonads neither male nor female initially to become testes Y Chromosome induces the indifferent This begins approximately during 6th 7th week of gestation Testes produce 2 types of hormones Androgens male hormones testosterone locally will act on the Wolffian duct system to induce internal male seminal vesicles vas deferens and epididymis reproductive structures and on the external genitalia to induce male external structures Mullerian duct inhibiting hormone MDIH will act on the mullerian duct system to cause them to degenerate Dihydrotestosterone DHT potent androgen causes the external genitalia to become male structures scrotum penis prostate gland The receptors only respond to testosterone and the cell changes the systemic testosterone in the blood to DHT o FEMAL DIFFERENTIATION no Y chromosome Androgens are absent and the Mullerian ducts will become the internal female reproductive structures oviducts uterus upper portion of vagina Androgens are absent so the female external structures will develop clitoris labia vagina Genetic Sex o Established at fertilization XX female XY male Internal Male Structures Ejaculatory Ducts lead to the urethra and junction of ducts of seminal vesicles and vas deferens Prostate Gland Cowpers Gland Homologous Structures It is clear that male and females are anatomically different but the reproductive strictures develop from the exact same tissues If androgens are present the tissues become male structures and without androgens they become female structures The structures are termed homologous structures Male Scrotum labia folded over Penis Cowpers Gland pre ejaculatory fluid Female Labia Majora Clitoris Bartholins s gland lubricant during sexual excitation Testes Ovaries Critical Role of the Y Chromosome We see that the y chromosome is necessary for the creation of the male reproductive structures Without a Y the default development will be female The androgens male hormones from the developing testes are critical Adrenogenital Syndrome AGS Can affect both genders roughly 1 in every 10 000 to 18 000 children are born with this condition The syndrome will cause Males excessive male hormones will cause quite a few things to occur o Go into puberty at an early age Females genitalia could look both male and female Treated by feminizing the genitalia SIDE NOTE Hormones and Sexual Differentiation of the Brain Males and females carry books differently Maybe because body posture and the way the limbs are held hip width hip shelf and arm length Most men have ring fingers that are longer than their index fingers but most women have longer index fingers than ring fingers o Digit ratio has been assumed to be related to the exposure of testosterone ICLICKER Answer C 1 If we prevented testosterone from being changed to DHT dihydrotesterone we would NOT find A epididymis B vas deferens C penis 2 The scrotum is homologous to the A Labia minora minor lips B Cowper s gland C Bartholin s glands D Clitoris E Labia majora major lips Answer E 3 If the theory about prenatal androgen exposure and digit length is true then we would expect to find in a person male or female with AGS A Ring finger longer than index finger B Index finger longer than ring finger 4 An individual with a genotype of XXY would have Answer A A Ovaries B Testes C Neither ovaries or testes Answer B Lecture 2 Sexual differentiation XY any time there is a Y testes will occur o H Y antigen will cause differentiation of testes o Testosterone will differentiate wollfian ducts into internal genitalia DIH will cause the external genitilia o MIH will inhibit mullerian ducts XX any time there isn t a Y an internal vagina will develop o Mullerian ducts will create the internal vagina structures o Absence of androgens will causes external female genitalia to develop Adrenogenital Syndrome genetic disorder from lecture 1 Androgen s coming from the a child s adrenal cortex and cause male external structures to develop Genetic sex is one thing but hormonal sex is another This syndrome illustrates the effects of male hormones androgens on the For Boys with XY chromosomes the excessive male hormones will cause development of a child quite a few things to occur o He might go into puberty at an early age have a deeper voice small testes an enlarged penis and a strong muscular system o He must be treated with steroids For girls XX the excessive male hormones will cause external genitalia to look like boy and girl because the genitalia develop at 12 weeks on outside and androgen bathes the outside o Inside she is completely o She would most likely surgery to reconstruct her genitalia feminization o Deficiency of hormones external the child on female undergo external surgery coritsol and aldosterone need to be treated with cortisone Just called hormone therapy Summary o Female with AGS will have ovaries oviduct uterus vagina be fertile and some masculinization of external genitalia Androgen insensitivity Syndrome AIS o All individuals have the genotype XY o 2 5 100 000 have this syndrome not always complete people could have mild form o Receptors are key to this syndrome the cells of the body will not respond to androgen from the abdominal testes o Wolffian ducts are insensitive to male hormones androgen so no male internal structures will develop and testes will remain in the abdomen o The Mullerian ducts however have regressed because the body does respond to MIH o They are female phenotypes but male genotypes External structures of the male o Penis o Erectile tissue erection is a vascular phenomenom Blood flows into the tissues gets trapped in the connective tissue and causes an erection Corpora cevernosa penis the spongy tissue that gets blood during an erection Corpus spongiosum penis more spongy tissue that gets blood during an erection Urethra also housed in a corpus spongiosum o Scrotum o Function to keep the testes about 5 degrees cooler ICLICKER 1 With the AGS XX would we find A Ovaries B Testes C Neither ovaries or testes Answer A 2 Will Mullerian ducts become internal female reproductive structures in an XX Answer A need MIH to prevent the internal female structures from developing and to get MIH you need testes 3 Will the Wollfian ducts become internal male structures in a XX AGS child AGS child A Yes B
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