Reproductive System Diploma Prep PDF

Reproductive System Study Guide Male Reproductive System Female Reproductive System Identify the structures of the male reproductive system Identify the structures of the female reproductive and describe their functions (epididy...

Reproductive System Study Guide Male Reproductive System Female Reproductive System Identify the structures of the male reproductive system Identify the structures of the female reproductive and describe their functions (epididymis, testes, system and describe their functions (ovaries, scrotum, vas deferens, prostate gland, Cowper’s gland, fimbriae, oviducts, uterus, endometrial lining, cervix, seminal vesicle, ejaculatory duct, urethra, penis) vagina) Distinguish developing sperm cells from their supporting Distinguish developing egg cells from their structures (seminiferous tubules, interstitial cells, Sertoli supporting structures (follicle cells, corpus luteum) cells, spermatogonia) Describe important features of egg cells (zona Describe important features of sperm cells (acrosome pellucida, corona radiata) cap, flagellum) Identify primary and secondary sex characteristics Identify primary and secondary sex characteristics of of females males STIs Explain how sexually transmitted infections can interfere with fertility and reproduction  Study Guide Hormonal Regulation Fertilization and Development Differentiate between chromosomal and anatomic sex Evaluate practical solutions to decreased fertility and describe Describe chromosomal factors and hormonal physiological or mechanical basis of different reproductive technologies. influence on formation of the gonads and reproductive Describe process of fertilization to produce a diploid zygote organs in male and female embryo and fetus. Describe processes of cleavage and implantation of blastula Identify principal reproductive hormones in males Explain role of hCG in maintaining corpus luteum post-implantation (GnRH, testosterone, FSH, LH) and explain how they Describe process of gastrulation and identify major tissues & organs that maintain male reproductive system through negative arise from development of the ectoderm, mesoderm, and endoderm. feedback Describe process of neurulation to form notochord. Identify principal reproductive hormones in females Identify and outline function of structures that support embryo (FSH, LH, estrogen, progesterone) and explain their (placenta, amniotic fluid, amion, chorion, yolk sac, allantois) interactions in maintenance of the menstrual cycle. Graph changes in estrogen, progesterone, FSH and LH Trace processes of embryonic and fetal development throughout first, levels in blood of a female through a single menstrual second, and third trimesters. cycle. Explain processes of parturition and lactation, and describe role of Explain how birth control pills act to prevent pregnancy. hormones in controlling these events (oxytocin & prolactin) Describe influence of environmental factors on embryonic and fetal development. Unit Exam Potential Breakdown of Questions ~12 questions ~3 male ~4 female ~5 embryology  Notes: pg. 2 - 5 Textbook: pg. 478 - 481 The Male Reproductive System Reproductive Systems are characterized by: - Gonads: gamete producing organs (testes vs ovaries) - Sex hormones: testosterone vs estrogen - Gametes: sex cells (sperm vs eggs) - Primary sex characteristics: reproductive organs - Secondary sex characteristics: features of the sexes not directly related to reproduction The Male Reproductive System SG: Spermatogonia - undifferentiated germ cells →the starting point for spermatogenesis. SC: Sertoli Cells - supporting cells in seminiferous tubules → provide nourishment and structural support and regulate spermatogenesis. M: Mature Spermatozoa - Fully developed sperm cells located near centre of seminiferous tubules, ready to be released into the ductal system. LS: Late Spermatids - nearly mature germ cells in later stages of spermiogenesis, located closer to the lumen than earlier stages. PS: Primary Spermatocytes - germ cells in first meiotic division→ found further from outside than spermatogonia but before secondary spermatocytes. IC: Interstitial Cells (Leydig Cells) - cells located in interstitial spaces between seminiferous tubules, responsible for producing testosterone. Testes: 2 Main Tissue Types 1. Interstitial cells: produce testosterone (aka Leydig cells) - testosterone: stimulates male secondary sex characteristics and control sperm production - testosterone release stimulated by luteinizing hormone (LH) Testes: 2 Main Tissue Types 2. Seminiferous Tubules: long coiled tubes in each testes that produce sperm - Sertoli cells: provide metabolic support for developing sperm - spermatogenesis stimulated by follicle-stimulating hormone (FSH) Spermatogenesis: - Sperm begin developing in walls of seminiferous tubules as spermatogonia - Developing sperm supported by Sertoli cells - Mature sperm transported to epididymis (duct) - Epididymis connects to vas deferens (storage duct) - Vas deferens leads to ejaculatory duct Best temp for spermatogenesis is 35°C → a bit colder than body temp! Spermatozoa - Acrosome (head): contains enzymes needed to dissolve protective layer around ovum allowing sperm to penetrate - Flagellum: allows sperm to propel themselves through female reproductive system - Mitochondria present along flagellum providing energy for mobility Pathway of Sperm Upon Ejaculation Testes (seminiferous tubules)→ epididymis → vas deferens → prostate → urethra Male Ejaculate Contributions (semen) Structure Contribution % of Ejaculate Testes Sperm 2% Seminal Vesicles Fructose (nourishment) 60% Prostate Gland Alkaline mucus (lubricate & neutralize 35% acids) Cowper’s Gland Alkaline mucus (lubricate, neutralize 3% acids) Male Hormone Feedback Loop - At puberty: hypothalamus produces GnRH which stimulates the anterior pituitary to release FSH & LH - FSH: stimulates seminiferous tubules to start producing sperm - LH: stimulates interstitial cells to produce testosterone - Testosterone: stimulates sperm production & secondary sex characteristics - Hormones regulated via negative feedback The Female Reproductive System Male vs Female: Gamete Production Males: Females: - Produce sperm cells daily starting at - Born with all oocytes present puberty (declines during andropause) (~ 400 000 immature eggs) - Produce several million per day - After puberty about 1 ova matures every 28 days until menopause - Approx. 400 mature ovum per lifetime (ovulation) Female Gonads: Ovaries - Site of oogenesis - Ova can survive in the fallopian tube/oviduct for 24 hours - No fertilization = endometrial lining is shed (menstruation)  Oogenesis: Ovum Production - Location: follicle cells of the ovaries - Once ovum is released, surrounding follicle cells form the corpus luteum - Corpus luteum = secretes hormones required for pregnancy but degenerates if ova isn’t fertilized A Mature Ovum: Two Key Layers: 1. Corona radiata: supplies vital proteins to the cell 2. Zona pellucida: protective coating only able to be penetrated by acrosome enzymes from a sperm cell Ovum = non-motile  Ovulation - Location = oviducts/fallopian tubes - Fimbriae sweep ova into duct, cilia move ova through the oviduct to the uterus - Fertilization occurs in fallopian tubes, if successful the fertilized egg moves to the uterus for implantation Uterus - Site of embryo maturation into fetus - 2 layers: - Myometrium: outer muscle layer, contracts for birth - Endometrium: inner glandular lining, provides nourishment for embryo - Shed during menstruation if no fertilization occurs Female Sex Hormones: Role of FSH & LH - Puberty begins when the hypothalamus triggers the release of LH and FSH from the pituitary gland. - FSH = stimulates development of female sex organs and follicle development within ovaries - Follicle releases estrogen as it develops - LH = triggers ovulation (signals egg maturation) Menstrual Cycle: 4 Phases 1. Flow phase (days 0-7) - Endometrium sheds - Low levels of all hormones 2. Follicular phase (days 7-14) - GnRH stimulates FSH release from pituitary → follicle in ovary matures - As follicle matures, estrogen is released → endometrium develops - Increasing estrogen → FSH release inhibited Menstrual Cycle: 4 Phases 3. Ovulatory phase (day 14) - Estrogen triggers increase in LH → signals release of mature ovum from follicle - After follicle release, estrogen levels decline - Follicle begins to form the corpus luteum  Menstrual Cycle: 4 Phases 4. Luteal phase (days 14-28) - Corpus luteum secretes estrogen and progesterone - Estrogen = promotes development of endometrium - Progesterone = stimulates endometrium development and inhibits LH (prevents further ovulation & firms cervix) - No fertilization = corpus luteum degenerates - Hormone secretion stops - Endometrial lining shed  Notes: pg. 12 - 14 Textbook: pg. 508 - 511 Fertilization & Implantation If fertilization occurs: sex determination Chromosomal sex - determined at fertilization If fertilization occurs: sex determination Anatomic sex - determined at ~ 7 weeks (Y chromosome encodes for testosterone) Fertilization: joining of male & female gametes (23 c) to form a zygote (46 c) - Occurs in the fallopian tube - Recall: zona pellucida protects the ovum  Fertilization Steps: 1. Sperm encounters corona radiata = begins secreting acrosome enzymes  Fertilization Steps: 1. Sperm encounters corona radiata = begins secreting acrosome enzymes 2. Sperm cells digest a path towards the plasma membrane of the egg (may have multiple sperm involved)  Fertilization Steps: 1. Sperm encounters corona radiata = begins secreting acrosome enzymes 2. Sperm cells digest a path towards the plasma membrane of the egg (may have multiple involved) 3. Once a sperm enters the egg, the plasma membrane depolarizes, preventing others from entering Fertilization Steps: 1. Sperm encounters corona radiata = begins secreting acrosome enzymes 2. Sperm cells digest a path towards the plasma membrane of the egg (may have multiple involved) 3. Once a sperm enters the egg, the plasma membrane depolarizes, preventing others from entering 4. Nuclei of the sperm and egg fuse resulting in a zygote  Textbook: pgs. 511 - 518 Notes: pg. 15 - 17 Gastrulation Cleavage: cell division without enlargement - Rapid cleavage results in a 16 cell zygote = morula - Occurs in fallopian tube - Morula reaches the uterus ~ 3-5 days after fertilization Morula enters the uterus: - Morula fills with fluid = blastocyst (two layers, trophoblast and inner cell mass) - Days 5 - 7 = blastocyst attaches to endometrium (implantation) - If successful by days 10 - 14 = officially “pregnant”  Post-Implantation - Trophoblast secretes human chorionic gonadotropin (hCG) - Maintains corpus luteum (continues secreting progesterone & some estrogen → maintains endometrium and prevents menstruation) - hCG declines after second month of pregnancy - Placenta able to secrete enough estrogen & progesterone to maintain endometrium Gastrulation : blastocyst → gastrula - Blastocyst changes during week 2 following implantation: - Amniotic cavity forms between trophoblast and inner cell mass (site of fetus development) - Inner cell mass flattens into 3 layers: ectoderm (outer), mesoderm (middle) and endoderm (inner) Pg 513 in Textbook - gastrula - Gastrulation = beginning of morphogenesis (formation of distinct structures) - Cell differentiation = cells develop to a particular shape and perform specific functions different from one another (different for each germ layer) Organ Formation Timeline Week 3 = formation of notochord and neural tube (will become brain and spinal cord through neurulation★), primitive “heart beat”, allantois forms (will become umbilical cord)  ★ Neurulation = folding of germ layers to form neural tube (will develop into brain and spinal cord) - Notochord sends signals to make the neural tube - Requires folic acid (absence may lead to spina bifida) Organ Formation Timeline Week 3 = formation of notochord (will become brain and spinal cord through neurulation), primitive “heart beat”, allantois forms Week 4 = formation of blood cells, lungs and kidneys begin to form, primitive arms/legs appear, head is visible Week 5 = eyes open (no eyelids/irises), brain cells undergo rapid differentiation Week 6 = brain continues to develop, limbs lengthen, gonads produce sex determining hormones Week 7 = organs and skeleton almost formed, external genitalia beginning to form, nervous system begins coordinating activity Week 8 = embryo the size of a paperclip, ~ 90% of organs established 4 Structures supporting the embryo 1. Amnion: filled with amniotic fluid, protecting the embryo during development and allowing movement (prevents limbs from sticking) 4 Structures supporting the embryo 2. Yolk sac: forms the digestive tract and produces the first blood cells and future gametes. In humans, it serves no nutritional purpose (shrinks after week 8) 4 Structures supporting the embryo 3. Allantois: foundation of the umbilical cord. Degenerates during second month, remnants become part of the bladder 4 Structures supporting the embryo 4. Chorion: outermost layer, forms the fetal portion of the placenta Functions of the Placenta Nutritional - Transports nutrients from mother to fetus - Stores nutrients Excretory - Transports waste from fetal blood to mothers blood Respiratory - Transports O2 from the mother to the fetus and CO2 from the fetus to the mother Endocrine - Secretes hormones (estrogen, progesterone and hCG) Immune - Transports antibodies from the mother to the fetus (passive immunity) Teratogens = substances resulting in fetal abnormalities (not filtered by the placenta) Eg. Alcohol: affects fetal nervous Eg. Thalidomide: used to treat morning system and brain development and sickness in the 1960s but caused birth physical development (FASD) defects Trimester 1 (weeks 1-12) - Embryonic period: weeks 1-8 - Chorion (placenta) secreting hCG → corpus luteum secretes progesterone - Fetal period: weeks 9-12 - Placenta, not corpus luteum now secreting most progesterone directly Trimester 2 (weeks 13-24) - Stronger heartbeat - Rapid brain growth, nervous system begins to function - Mother begins to feel movement - Fetus unlikely to survive birth at this point Trimester 3 (weeks 25-38) - Rapid brain development and organ maturation - Fetus nearly doubles in size Hormones During Pregnancy hCG: thickens endometrium, prevents menstruation, promotes fetal organ growth and differentiation Estrogen: maintains endometrium, promotes breast development for future lactation Progesterone: maintains endometrium, prevents premature labour, inhibits lactation Childbirth = Parturition - Contractions regulated through positive feedback mechanisms - Relaxin (from placenta) promotes cervix dilation and loosens ligaments - After birth, placenta is expelled and uterus contracts to (almost) normal size Post Birth: Lactation - Pituitary secretes prolactin → stimulates milk production - Pituitary secretes oxytocin → contraction within mammary lobules causing lactation - Stimulated by infant suckling motions through nerve endings - Breast milk provides infant with antibodies - Infant immunity underdeveloped for the first 6 months