D’YOUVILLE COLLEGE
BIOLOGY 108/508 - HUMAN ANATOMY & PHYSIOLOGY II
LECTURE # 25
REPRODUCTIVE SYSTEM
FEMALE
1.
Anatomy of Female Reproductive Tract (fig. 27 - 10):
a. Ovaries (fig. 27 - 11): primary sex organs in pelvis; produce ova; secrete sex
hormones
• primordial germ cells form follicles (primary oocyte + granulosa cells)
• granulosa cells nourish ovum & produce estrogens, progestins
b. Uterus (fig. 27 - 12):
• body, fundus, cervix, wall: perimetrium, myometrium, endometrium
(fig. 27 - 13)
c. Uterine Tubes: terminate near ovaries with fimbriae; ciliated lining
d. Vagina (Birth Canal): inferior to uterus, lined with mucosa
• vaginal orifice may be partially closed by the hymen in virgins
e. Vulva: labia majora and labia minora enclose vestibule containing clitoris
(homologue of penis), opening of urethra and vaginal orifice; fleshy pad of fat (mons
pubis) located in front of vestibule at anterior ends of labia (fig. 27 - 14)
2.
Mammary Glands (fig. 27 - 15):
• modified sweat glands serving to produce milk to nourish newborn
• glandular units (alveoli) empty into lactiferous ducts that communicate
with openings in the external nipple (surrounded by areola)
3.
Physiology of Female Reproduction:
a. Hormonal Relationships (figs. 27 - 19 & 27 - 20):
• Gonadotropin Releasing Hormones: regulate pituitary gonadotropins:
• Follicle Stimulating Hormone (FSH): for follicle growth in ovary
• Luteinizing Hormone (LH): for follicle maturation, estrogen secretion
• LH surge (near mid cycle) causes ovulation; LH stimulates follicular
residue to form corpus luteum which secretes progesterone and some estrogens; LH
maintains corpus luteum
• Estrogens: proliferation of mammary glands and glands of endometrium;
enlargement of pelvic dimensions, development of secondary sex characteristics
(female distribution of body fat, rapid but shortened growth in early puberty,
development of pubic and axillary hair)
• Progesterone: promotes secretion by mammary gland & endometrium
b. Ovarian Cycle (figs. 27 - 17 & 27 - 18):
i. Follicular Phase (Preovulatory Phase): (approx. first 14 days) follicles
enlarge, become vesicular with primary oocyte completing first meiosis ---> mature
(Graafian) follicle (ready for ovulation); mostly directed by FSH from anterior
pituitary with help of LH
Bio 108/508
lec. 25 - p. 2
ii. Luteal Phase (Post ovulatory Phase): LH surge triggers ovulation and
development of corpus luteum; progesterone level rises and produces a
progressively strengthening negative feedback on anterior pituitary inhibiting
further output of gonadotropins
Bio 108/508
lec. 25 - p. 3
c. Uterine Cycle (fig. 27 - 20):
i. Proliferative Phase: estrogens promote thickening of endometrium (rich
blood supply, extensive glandular development)
ii. Secretory Phase: progesterone from corpus luteum promotes glandular
secretion, preparation of endometrium for implantation
iii. Menstrual Phase: in absence of implantation, negative feedback on
anterior pituitary causes deterioration of ovarian corpus luteum and resulting decline
in progesterone leads to sloughing off of endometrium constituting the menstrual
discharge (4 - 5 days)
d. Regulation of Non-pregnant Reproductive Cycle:
• following menses, pituitary FSH and LH rise, initiating next follicular
phase of ovary
• estrogens from maturing follicles promote proliferative phase of uterine
endometrium
• rising estrogen levels cause positive feedback upon anterior pituitary
causing gonadotropin surges (especially LH); ovulation ensues
• corpus luteum formation in ovary marks beginning of luteal phase with
progesterone dominating hormonal picture
• progesterone promotes secretory phase of uterine endometrium and
negative feedback inhibition of AP gonadotropins
• corpus luteum regresses (lack of LH support); endometrium deteriorates
with lack of progesterone support; menses begins