The Reproductive System

1. PART 3 The Reproductive System

2. The Ovarian Cycle • Follicular phase • Days 1 – 13 of the ovarian cycle • 6 – 12 primordial follicles stimulated to develop • Growth stimulated by FSH from anterior pituitary • Primordial follicle becomes a primary follicle • Zona pellucida – glycoprotein coat surrounding oocyte • Theca folliculi – internal layer secretes hormones

3. The Ovarian Cycle • Follicular phase (continued) • Antrum forms • A fluid filled cavity between granulose cells • Primary follicles become a secondary follicle • Corona radiata – coat of granulosa cells surrounding oocyte • Secondary follicle enlarges and becomes • Visicular (Graafian) follicle – ready to be ovulated

4. The Ovarian Cycle • Ovulation • Occurs about halfway through each ovarian cycle (Day 14) • One mature oocyte exits from one ovary • Enters peritoneal cavity • Swept into uterine tube • Sudden increase in LH is signal for ovulation PLAY Ovulation

5. The Ovarian Cycle • Luteal phase • Occurs after ovulation – days 15 – 28 • Remaining follicle becomes a corpus luteum • Secretes progesterone • Acts to prepare for implantation of an embryo • If no implantation • Corupus luteum dies and becomes a corpus albicans

6. Oogenesis • Takes many years to complete • Primordial follicles are arrested (stalled) in meiosis I • Surge of LH also causes primary oocyte to compete meiosis I

7. Oogenesis • Oogenesis produces only one ovum and three polar bodies • Polar bodies do not contribute to developing embryo • Meiosis II is completed only is sperm penetration occurs

8. Oogenesis Figure 24.15

9. The Uterine Tubes • Receive ovulated oocyte • Parts of the uterine tube • Infundibulum – distal end of uterine tube • Surrounded by fimbriae • Ampulla – middle third of uterine tube • Usual site of fertilization • Isthmus – medial third of uterine tube

10. The Uterine Tubes Figure 24.12

11. The Uterus • Lies anterior to rectum – posterior to bladder • Anteverted (anteflexed) usual position of uterus • Parts of the uterus • Fundus – rounded superior portion • Cervix – “neck” of uterus • Cervical canal – communicates with vagina inferiorly • Internal os – opening connecting with uterine cavity • External os – inferior opening of cervix

12. The Uterus PLAY Female Reproductive Anatomy Figure 24.11

13. The Uterine Wall Figure 24.18b

14. The Uterine Cycle • Series of cyclic phases of the endometrium • Phases coordinate with the ovarian cycle • Endometrial phases directed by FSH and LH • Phases of uterine cycle • Menstrual phase – days 1 – 5 • Stratum functionalis is shed • Proliferative phase – days 6 – 14 • Secretory phase – days 15 – 28

15. The Uterine Cycle • Series of cyclical changes to endometrium • The phases of uterine cycle • Menstrual phase (days 1– 5) • Proliferative phase (days 6 – 14) • Secretory phase (days 15 – 28)

16. The Menstrual Cycle Structural and hormonal changes Figure 24.19a, c

17. The Menstrual Cycle Figure 24.19b, d

18. The Vagina • Consists of three coats • Adventitia – fibrous connective tissue • Muscularis – smooth muscle • Mucosa – marked by transverse folds • Consists of lamina propria and stratified squamous epithelium • Hymen – an incomplete diaphragm • Fornix – recess formed at the superior part of the vagina

19. The Vagina Figure 24.12

20. The Vagina Figure 24.11