Human Reproduction and Fetal Development PDF

Human Reproduction and Fetal Development Annie Nelson BSN RNC-MNN NUR 105 S25 North Country Community College, Ticonderoga Female Anatomy  Ovaries  X2  Thousands of follicles present at birth  Each has an egg!  Follicles also secrete estrogen  H...

Human Reproduction and Fetal Development Annie Nelson BSN RNC-MNN NUR 105 S25 North Country Community College, Ticonderoga Female Anatomy  Ovaries  X2  Thousands of follicles present at birth  Each has an egg!  Follicles also secrete estrogen  Hormone disorders often associated w/ infertility Internal organs Ovaries Fallopian tubes Uterus Vagina Two small glands about Provide a channel for A muscular triangle- A 4- to 6-inch elastic the size and shape of the sperm to travel to shaped organ that muscular tube that almonds that are on the egg and to transport provides the extends from the cervix either side of the uterus the fertilized egg into environment for fetal to the external vaginal slightly behind and the uterus growth opening below the fallopian Top portion: Fundus Tissue is composed of tubes Bottom portion: Cervix smooth muscle and Store approximately Provides a protective elastic connective one-half million eggs entrance to the uterus tissue, and lined with and secrete estrogen Very elastic and has stratified squamous and progesterone the ability to stretch to epithelium allow for childbirth Two main functions are 2 Coats: for sexual intercourse Muscular coat and childbirth Inner mucous membrane (rugae) Female reproductive cycle Begins on the first Hormones involved day of menstrual include the follicle- bleeding and ends stimulating on the first day of hormone, luteinizing the next menstrual hormone, estrogen, bleeding and progesterone  Anterior lobe of pituitary secretes follicle-stimulating hormone (FSH), which stimulates the development of a follicle in the ovary Follicular Maturing egg follicle secretes estrogen, which thickens the phase: endometrium to prepare for the implanting of the fertilized egg Elevated estrogen levels cause FSH to stop and luteinizing hormone (LH) is released by the pituitary gland Luteal phase: LH peaks on LH converts the approximately day 14 ruptured follicle into Begins on the day the of the cycle, causing the corpus luteum, egg is released ovulation or the which secretes release of the egg progesterone from the follicle Progesterone If egg is not fertilized, completes the the corpus luteum Uterine lining sheds development of the degenerates, dropping and menstrual cycle uterine lining in levels of progesterone begins again preparation for a and estrogen fertilized egg  External organs: Scrotum - made of two sacs that hold the testicles, the epididymis, and the beginning of a spermatic cord Penis - made of cavernous tissue that allows erection, and expels semen upon sexual climax (ejaculation) Internal organs: Testicles The reproductive glands of the male Male Testes Have cells that produce testosterone, which promotes the development of male reproductive organs and the secondary male characteristics Reproductiv Seminiferous tubules The site of germination and maturation of cells into spermatozoa Epididymis e System Facilitates sperm motility Vas deferens Ducts that transport mature sperm from the epididymis to the ejaculatory ducts Prostate gland Provides additional fluid to the sperm Seminal vesicles Two pouch-like sacs that create sugar-rich fluid to provide energy to the sperm Ejaculatory ducts Formed by the fusion of vas deferens and the seminal vesicles, and empty into the urethra Urethra Carries urine and semen out of the body  Fertilization Occurs when the sperm and the egg (gametes) meet in the same place at the same time after intercourse Fertilization occurs in the outer third portion of the fallopian tube Only one sperm will penetrate the egg’s outer layer and fertilize the ovum Upon fertilization, the zygote divides during mitosis and travels down the fallopian tube to implant in the uterine lining Estrogen and progesterone levels remain high Human chorionic gonadotropin (hCG) is produced to support the development of the embryo Elevated levels of hCG can be detected by a blood test 11 days after conception and in urine tests 12-14 days after conception Fertilization Embryo Blastocyst In blastocyst The stage of A maturing stage, embryo development embryo in which implants 7-10 between the some cell days after fertilized ovum differentiation has fertilization into and the fetus occurred the uterine endometrium Placenta  The most amazing organ there ever was!!  An organ that develops at the site of implantation to sustain the fetus during intrauterine life or the gestation period  Provides oxygen and nourishment  Connect indirectly with mother's blood vessels  Heavily involved in hormones  Progesterone - supports the endometrium; calms and quiets the uterine muscle  Estrogen - stimulates breast development for breastfeeding and the growth of the myometrium; improves blood flow between placenta and fetus  hCG - stimulates the corpus luteum for estrogen and progesterone production; used to determine pregnancy  Human placental lactogen - assists with milk preparation and increases the mother’s metabolism during pregnancy  Relaxin - maintains pregnancy together with progesterone; causes relaxation of pelvic ligaments Umbilical Cord Expectations Normal = 3 vessel cord, 2 arteries and 1 vein Not your “typical” arteries and veins Placental flow 2 vessel cords  IUGR (intrauterine growth restriction) Abnormalities generally discovered in utero https://www.youtub e.com/watch?v=-IR kisEtzsk Multiple Pregnancy  Multiple pregnancy occurs when the woman has two or more embryos in the uterus  Identical - embryos from the same egg  Fraternal - embryos from two or more eggs  Monozygotic twins - form when a single fertilized egg splits; separate amniotic sacs but share a placenta; always the same sex  Dizygotic twins - two eggs fertilized by two separate sperm; each embryo has its own amniotic sac and placenta; with similarities but will not have the exact same genetic material Multiple Pregnancy (continued)  Contributing factors for multiple pregnancy:  Older than age 35  African-American descent  Family history of twins  Undergone fertility treatment  Previous multiple births Effects of Teratogens on Fetal Development  Medications and substances can be harmful to the developing fetus  Use as little medication as possible during pregnancy  Teratogen  Any substance that may cause a birth defect  Most substances can cross the placenta from the mother and the fetus and cause abnormalities  Susceptibility depends on period of fetal development Fetus is very vulnerable to the effects of medications during the first trimester so it is crucial to verify the date of the woman’s last menstrual period. Any concern of pregnancy must be reported Fetal Developmen t First trimester (Week 1-12) Three germ layers A critical time of are created within 2 rapid changes to the weeks after fertilized cell; fertilization as development of foundation for the major organs and body tissues and structures organs 2nd and 3rd Trimesters Second Organs and structures develop trimester The woman becomes more aware (Week 13-28) of growing fetus Third The fetus gains weight, matures, trimester and prepares for life outside the (Week 29-40) uterus