1. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Reproduction, Early Development, Pregnancy l 1. From 2 cells …a 3-layer embryo …a yolk sac, amniotic cavity, chorionic cavity …a placenta l 2. Pregnancy and Childbirth Changes to female anatomy Labor and birth

2. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Ovulation l 1o oocytes arrested in Meiosis I in female fetus l After puberty, 1 primary oocyte/month completes Meiosis I as follicle matures l Follicle ruptures-- ATTENTION--CELL LOOSE IN CELOM l Oocyte enters Fallopian tube l If fertilization occurs, Meiosis II occurs and oocyte becomes ovum

3. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Ovulation and Meiosis Fig. 24.15

4. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Spermatogenesis l Sperms form in walls of seminiferous tubules l Spermatogenic cells within sustentacular cells l Meiosos proceeds as spermatocytes move towards lumen (4 sperm from each spermatocyte) l Seminiferous tubule  rete testis  head/body/tail epididymis  vas deferens (through spermatic cord around bladder)  urethra Seminiferous tubule  rete testis  head/body/tail epididymis  vas deferens (through spermatic cord around bladder)  urethra Fig. 24.3

5. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Sustentacular cells l Form thick epithelial lining of seminiferous tubules l Tight junctiones between keep sperm proteins from entering bood l Produce testicular fluid which helps move sperm l Concentrate testosterone to stimulate sperm production l Produce inhibin which slows sperm production Fig. 24.4

6. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy First week of development Oocyte  (fertilization)  zygote  4-cell stage (2 days)  morula (ball)  blastocyste  inner cell mass (embryo) Trophoblast (extraembronic membranes) From oocyte to blastocyst Fig. 3. 3

7. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy

8. Implantation l Endometium ready for implantation l Blastocyst implants with ICM against uterine wal l Ectopic pregnancy--implantation outside built-up endometrium (potential for bleeding since embryo stimulates vascularization)

9. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Endometrium l Two layers –Stratum basalis –Stratum functionalis l Stratum functionalis builds up each month in response to ovarian hormones l Uterine glands secrete glycoproteins--nutrients for potential zygote--into uterine cavity l At menstruation, functional layer self-digests, spiral arteries kink and constrict so cells die. l Just before menstrual flow starts, spiral aa. Open wide, capillaries burst and functional layer sloughs off. Fig. 24.18

10. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Endometrium and menstrual cycle Fig. 24.19

11. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Endometrium and menstrual cycle l Menstrual Phase (Days 1-5): Sloughed Functional layer of endometrium expelled through vagina as menstrua flow l Proliferative phase (Days 6-14): In response to estrogen from growing ovarian follicle, new functional layer elaborates l Ovulation (about Day 14) l Secretory phase (Days 15-28): –Spiral aa. Elongate and coil –Uterine glands secret glycoproteins –More estrogen (and progesterone) from corpus luteum l If pregnancy, secretory phase continues due to embryonic estrogen production l If no pregnancy, corpus luteum degenerates, estrogen drops leading to menstruation

12. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy l Implantation with ICM towards uterine wall l Trophoblast –Cytotrophoblast (cells around ICM) –Synctiotrophoblast (synctium of cells that becomes placenta) Meanwhile…back in the embryo Fig. 24.25

13. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Placenta formation l Lacunae form within synctiotrophoblast--maternal blood fills these spaces l Vili form with embryonic capillaries down middle Fig. 24.25

14. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Placenta formation l Villi bathed in maternal blood in lacunae--exchange of nutrients, O2, CO2 l After 13 weeks, full placenta--pancake-shaped organ. Fig. 24.25

15. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Other extraembryonic tissues l Cellular trophoblast forms amnion, yolk sac l Fetal cells shed into amniotic cavity which fills with fluid from fetal kidneys extreted through ureter, bladder, urethra l Amniocentesis--sample of amniotic fluid taken with hypodermic needle l Part of yolk sac “sucked” into embryo to form endermic bladder Fig. 3.4

16. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Embryo proper l ICM forms hypoblast (yellow-- becomes endoderm) and epitblast (blue--becomes ectoderm) l See handout for all adult derivatives of embryonic tissues--HOW FAR WE’VE COME!! Fig. 3. 4Animated movie of fetal deveopment http://www.cvillepregnancy.org/fetal.html

17. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Pregnancy--changes in female anatomy l Shift in organs –Bladder, rectum pushed superiorly, squeezed--change in urination, defecation patterns –Stomach compressed--eat more often, less at each meal –Immune response may change appetite to avoid possible poisons for fetus l Postural changes to compensate for anterior weight l Breasts enlarge--first milk production

18. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Birth l Stage 1. Dilation Stage –Ligaments loosen –Cervix dilates l Stage 2. Expulsion –Baby moves through pelvic girdle--head is rotated 90 degrees –Floor of pelvis l Kegel exercises l Perineal support l Avoid ripping or episiotomy –Baby skull--sutures not fused, bones can be slide on top of each other giving pointed look l Stage 3. Placenta. –Detaches and is expulsed within one hour.

19. Frolich, Human Anatomy, Reproduction, Early Dev., Pregnancy Fig. 24.27