Fundamentals of Human Reproduction 03 20 2013 Prenatal in utero development of the male and female reproductive structures The physical difference between male and female reproductive structures 2 27 13 Sexual Differentiation Genetic sex Established at fertilization o XX female o XY male Finger Length back to Sexual Differentiation become testes The testes produce hormones structures and epididymis Male Sexual Differentiation Most men s ring finger is longer than index the opposite is true for women The Y chromosome induces the indifferent gonads neither male or female to Androgens reproductive structures and on the external genitalia to induce male external will act on the Wolffian duct system to induce internal male Wollfian ducts respond to androgens to form seminal vesicles vas deferens The internal ejaculatory ducts lead to Urethra Junction of ducts of seminal vesicles External genitalia in the male respond to a potent androgen called dihydrotestosterone to become male structures including Srotum Penis Prostate gland Receptors only respond to testosterone Female Sexual Differentiation If androgens are absent the Mullerian ducts will develop into internal female The external female structures develop into this occurs with no hormone reproductive structures Oviducts Uterus Upper portion of the vagina involvement Clitoris Labia Rest of the vagina Homologous Structures It is clear that males and females are anatomically different but the reproductive structures develop from the exact same tissues If androgens are present the tissues become male structures and w o androgens they become the female structure Srotum Labia Majora Penis Clitoris Cowper s glands Bartholin s glands Testes Ovaries They come from the same tissues and serve the same function The Critical Role of Y Chromosomes It is the androgens from the developing testes that are critical Andrenogenital Syndrome Affects both genders and roughly 1 in every 10 000 to 18 000 children Causes an excess of male sex hormone to be produced Male characteristics will form 03 20 2013 For boys has a Y For girls no Y Basically an enhancement in puberty Genitalia could look like both genders o Ambiguous genitalia Treatment for AGS Feminization of external genitalia Treated with cortisone hormones and electrolytes Summary of AGS A female with AGS Ovaries Oviduct Uterus Vagine Is fertile Has some masculinization of external genitalia Androgen Insensitivity Syndrome 03 20 2013 Wolffian ducts are insensitive to male hormones so no male internal structures form 2 5 out of 100 000 births All individuals will have the genotype of XY The cells of the body do not respond to androgens except testes which remain in the abdomen No female internal organs But has the body build of a female External Structures of Male Penis Erectile tissue o Corpora cavernosa penis o Corpus spongiosum penis Urethra Scrotum 03 20 2013 3 4 14 Male Circumcision Numerous studies in Africa found that male circumcision MC significantly reduced the incidence of male HIV infection No protective effect of MC on females and HIV transmission Circumcision lowers risk of STDS Internal Structures of Male Testes produce male hormones androgens Leydig cells Seminiferous tubules Both of these are under the control of the anterior pituitary hormones sperm production Epididymis sperm mature here Vas deferens storage area for sperm cells Seminal vesicles thick mucus secretion essential for motility of sperm cells Ejaculatory ducts lead to urethra and junction of ducts of seminal vesicles and vas Prostate gland thin milky fluid helpful in sperm motility and buffers sperm cells while deferens in female tract Cowper s gland pre ejaculatory emission External Structures of Female 03 20 2013 o Forms protective hood over clitoris Called the vulva Labia majora Labia minora Clitoris Internal Structures of Female Vestibule of the vagina Urethral orifice Vaginal orifice Hymen thin membrane that covers vaginal orifice to varying degrees 03 20 2013 3 6 13 Bartholin s glands Mons pubis Ovaries egg and hormone production Fallopian tubes fimbriae cover surface of ovary Uterus Perimetrium outer layer Myometrium muscular layer Endometrium inner layer Vagina extends from vaginal orifice up to cervix Reproductive Phsiology Endocrinology targets surface system The study of ductless glands and their secretions called hormones Hormones are released directly into blood stream and have very specific A gland with a duct would be a sweat gland with sweat released on skin Neuroendocrinology the study of how the nervous system controls the endocrine Hypothalamus neurosecretory cells are located here and produce neurohormones Posterior pituitary attached to the hypothalamus via NERVE CELLS stores neurohormones made in hypothalamus 03 20 2013 Anterior pituitary gland attached to the hypothalamus via BLOOD VESSELS and make its OWN HORMONES and the release is controlled by neurohormones from Neurohormones from hypothalamus are called releasing hormones or releasing hypothalamus factors Gonadotropin hormone releasing hormone GnRH is a releasing factor from hypothalamus that controls Follicle Stimulating Hormone FSH and Luteinizing Hormone LH from anterior pituitary gland Gonadotropins FSH and LH allow sperm and egg production to occur Negative Feedback System The hypothalamus anterior pituitary gonadal system or axis Talk about AC Set point 67 degress Furnace Controller Comparator Sensor furnace what to do Now biological system The sensor senses the temp comparator compares to set point controller tells the 03 20 2013 Hypothalamus cid 223 GnRH Anterior Pituitary cid 223 FSH cid 223 LH Ovaries In a convent ovaries stop functioning Levels of estrogen and progesterone drop Hypothalamus boosts GnRH which causes the anterior pituitary to pour out FSH and LH 03 20 2013 3 18 13 Answer No Clicker Question Frank is using Viagra Will this influence testicular hormone levels Viagra just increases blood flow to the penis Reproductive Physiology Male reproductive physiology compared to female reproductive system Male is tonic constant vs female which is cyclic Menstrual Cycle Menarche onset of first menstrual flow Menopause the termination of menses Menstruation the monthly buildup and sloughing off of the endometrium LH and FSH peak in the middle of the cycle Day 1 is the day of the first flow Estrogen and progesterone peak before menstruation The 1st half of the cycle is dominated by estrogen Progesterone predominates at the 2nd
View Full Document
Unlocking...