Module 12: Reproductive PYSO PDF

Module 12: Reproductive PYSO Created @December 6, 2024 9:01 AM Class PYSO001 Reviewed Biological Sex A complicated answer that often involves chromosomal sex and gonadal sex Even when loo...

Module 12: Reproductive PYSO Created @December 6, 2024 9:01 AM Class PYSO001 Reviewed Biological Sex A complicated answer that often involves chromosomal sex and gonadal sex Even when looking at the science of it, there ii no perfect all inclusive answer yet It all starts with Gametes gamete: the reproductive cell for each cell Oocyte / egg cell: female gamete Sperm: male gamete Zygote: is the fertilized egg, which eventually becomes an embryo then a fetus Sex Organs Sex organs help to produce the gametes are gonads, which include testes and ovaries Internal genitalia - accessory glands that help to connect the gonads to the external environment Module 12: Reproductive PYSO 1  Gonads Males testes produces sperm (gamete) and testosterone (hormone) Females ovaries produce eggs or oocytes (gamete) and estradiol and progesterone (hormones) *all cells start out as undifferentiated germ cells, precursor cells that will become the sex cells that produce eggs and sperm Sperm Production up until puberty, the male boy has only developed germ cells, during puberty, an uptake in hormone secretion from the hypo, spermatogonia will undergo meiosis to create sperm cells Egg Production egg production is also known as oogenesis It’s the secondary oocyte that gets released during ovulation Stages of Oogenesis 1. Oocytogenesis during fetal development, start at week 10 and completes around brith Module 12: Reproductive PYSO 2  Results in the formation of primary oocytes (which will later develop into secondary oocyte) When a female is born, she has the primordial follicle that will create her children 2. Ootidogenesis results in the formation of secondary oocytes 3. Formation of Ovulm Sex Determination each uncleared cell in the body, except sperm and eggs, contains 46 chromosomes, diploid cell 22 pairs of autosomal chromosomes (hair color, blood type, etc) Sex Chromosomes Determines the genetic/chromosomal sex of that individual Chromosomal female: XX Chromosomal male XY Variations in Sex monosomy: a type of nondisjunction Module 12: Reproductive PYSO 3  nondisjunction: is failure for the chromosomes to separate properly during meiosis The offspring is only receiving one sex chromosome instead of two Turner Syndrome: a case where the offspring only receives the X chromosome from the mother Polyploidy the incomplete separation of homologous during meiosis results in a zygote with too many chromosomes There are more variations with this, XXY ( 47 chromosomes) Klinefelter syndrome XYY Jacob’s Syndrome: symptoms include being way above average height and below standard intelligence milestones XXX (Trisomy X) individual appear as a normal female, undistinguishable, except for by karyotype Differentiation of Reproductive Structures First 6 weeks of development are the same, then at week 7 Bipotential Gonad, is the stage of development the fetus is in at this time. It’s a stage where you are in a middle stage where you can go either way Medulla, Cortex, and two ducts, Mullerian duct, Wolffian duct If the embryo has the SRY gene, the bipotential gonad will be triggered to develop into testes and if it isn’t present then will later be developed into ovaries SRY Gene Module 12: Reproductive PYSO 4  the driving force in influencing the biopotential gonad into developing into testes The absence of this gene on the X chromosome causes the gonads to develop into ovaries Male Embryonic Development the SRY gene will trigger the medulla so it will develop into testes Anti Mullerian hormone will cause the Müllerian duct to disappear through degeneration, leaving behind the Wolffian duct. Wolffian duct will later develop into the vas deferens, the epididymus, DHT is a strong androgen and responsible for the regulation of the development of the male external genitalia If little DHT, the prostate and external genital don’t develop during these stages The Testes will start to make 3 hormones (around week 7) testosterone Dihydrotestosterone (DHT and is a more potent form of testosterone) Anti Mullerian Hormone Female Embryonic Development no SRY gene At around week 7, that will be the signal that the cortex will develop into the ovary Module 12: Reproductive PYSO 5  Since the ovary isn’t producing testosterone in this stage, the Wolffian duct disappears/degenerates The duct that further develops is the Mullerian Duct, and develops into more female structure such as the vagina, uterus, and the fallopian tubes The Ovary produces 2 hormones estradiol + progesterone Bipotential Stage genital tubercle, urethral groove, urethral fold, anus, labioscrotal swelling DHT regulates the development of external genital. DHT is only produced by the testes Hormones impact external genitalia in the bipotential phase of the fetus Intersex Individuals The general term used for a variety of situations in which a person has variation in HPG - AXIS starts in the hypothalamus and releases the GnRH (gonadal releasing hormone) - then to the Anterior Pituitary Gland releasing LH and FSH - Follicle Stimulating Hormone will tell the gonad will create gamete production - Lutenizing Hormone affect the endocrine cells Module 12: Reproductive PYSO 6  Female HPG - Axis The female HPG axis controls the required physiological changes occur in both the ovaries and uterus every month during the menstrual cycle Menstrual Cycle approx 28 days Begins with the removal of the endometrium (uterine lining) Ovarian Cycle development of the ovarian follicle Production of hormones by the ovary to prepare the oocyte to be released (ovulation) and prepare the uterus for potential implantation if fertilization occurs The release of the oocyte during ovulation day Uterine Cycle begins with the removal of the endometrium Begins the preparation for the potential implantation of the embryo Three phases of the Ovarian Cycle 1. Follicular Phase 2. Ovulation Phase 3. Didn’t get it Graph of the Menstrual Cycle Module 12: Reproductive PYSO 7  Day 0 - Day 28 On Day 14, LH and FSH increase, with LH with a sharp increase What is the relationship between FSH, LH + and Estradiol, Progesterone? FSH and Estradial have a negative feedback loop relationship Feedback Loop: Regulated Variable: levels of Estradiol There is a negative feedback loop Negative Feedback: Slide 30 Positive Feedback Loop just prior to ovulation there is a switch to a positive feedback loop of the female HPG axis High levels of estradiol trigger a switch to positive feedback, where High levels of Estradiol trigger the hypothalamus to release GnRH The surge in LH and estradiol facilitates the release of the second oocyte Ovulation Neural Progesterone: triggers GnRH release from the hypothalamus → more LH to be secreted from the anterior pituitary → more estradiol produced by Module 12: Reproductive PYSO 8  the ovary Across the Ovarian Cycle The ovarian cycles refers to the growth and maturation of an oocyte in preparation for fertilization Follicular Phase Days 1 - 14 Is marked by an increased for FSH secretion by the Anterior Pituitary Gland We start off with the primary (primordial follicle), then one is selected to undergo the maturation process During this phase both the follicular cells (the grainy cytoplasm also known as the follicle) and egg(secondary oocyte) are developing. Ovulation Phase Day 14 Marked by a surge or dramatic increase in LH , triggering the release of the secondary oocyte The secondary oocyte once it is released by the ovary, now is able to be fertilized If the secondary oocyte becomes fertilized, then the left over follicle, is now a corpus luteum, and will mature into a mature corpus luteum. The corpus luteum will die if there is no fertilization, and becomes corpus albicans Across the Uterine Cycle Module 12: Reproductive PYSO 9  Uterus Anatomy Review uterus is made up of three layers, endometrium, myometrium, perimetrium (From innner to outer) The myometrium is thick tissue that is also contractile, thickest and majority of the uterine wall The perimetrium, in the last thin layer The Uterine Cycle the uterine cycle refers to the preparation of the uterine lining for pregnancy Menses (lasts approx 7 days) the shedding of the uterine lining called the endometrium, from the previous menstrual cycle Proliferative Phase estrogen levels increase, causing the uterine wall, to thicken and prepare for another potential egg to implant itself after ovulation Secretory Phase the longest of the three phases, lasting from day 14 - 28 Progesterone stimulated by LH is the dominant hormone during this phase to prepare the corpus luteum and the endometrium for possible fertilized ovum plantation What happens of Fertilization Occurs? uterine endometrium (lining) will be maintained by Module 12: Reproductive PYSO 10  Release of progesterone from the corpus luteum Followed by the release of hCG (human chorionic gonadotropin) which maintains the corpus luteum until the 7th week of development - hCG is what is tested during a pregnancy test Placenta produces its own Hormones From week 7 and beyond - the placenta itself will produce progesterone, which maintains the endometrium placenta produces estradiol and progesterone which at high levels will block the GnRh secretion from the hypothalamus Placenta also produces hPL (human placental lactogen) Birth What changes occur to prepare for delivery of the fetus ? increasing levels of corticotropin-releasing hormone from the placenta a few weeks prior to delivery During delivery progesterone levels decrease Oxytocin levels increase Inhibin levels increase oxytocin and inhibin will trigger the increased stretch of the cervix which triggers additional increases the stretch of the cervix (positive feedback) Male Reproductive System Module 12: Reproductive PYSO 11  accessory glands prostate Bulbo urethrol gland Seminal vesicles Male Reproductive Physiology Gonads (testes) Testes produces sperm Leydig cells are the cells within the testicles that produce and secrete testosterone and DHT Sertoli cells receive that testosterone in over to mature sperm Sertoli Cells produce hormones and paracrine molecules involved with control of hypothalamus-pituitary-gonad axis and the testes directly Anti Mullerian Hormone + Inbhin / Activin + Androgen Binding Protein Leydig Cells produce androgens Such as testosterone and dehydroepiandrosterone (DHEA) Which both of these increase sperm production Module 12: Reproductive PYSO 12  Male HPG Axis Start with Hypothalamus secreting GnRH → Follicle Stimulating Hormone + LH from the AP are released → LH triggers the Leydig cells Testosterone for to the Sertoli cells FSH enters the sperm cella and binds to the Sertoli cell, and leads to the creation of the Androgen Binding Protein (keep test local to the testes) Male Reproductive Physiology Job of the accessory glands is to secrete seminal fluid (99% of semen) Components of seminal fluid mucus Water Nutrients Buffers Enzymes Prostaglandins Zinc Module 12: Reproductive PYSO 13