Female Reproductive System By: Han Yi

Composition: Internal genitals organs: ovaries oviducts uterus vagina External genitalia: vulva External genitalia: mons pubis, labia majora, minora, clitoris, vestibule, opening of the vagina, external urethral orifice. vulva

Functions: (l) Ovaries: produce ovum & secrete female sexual hormone; (2) Oviducts: convey ovum & spermatozoa , the place fertilization take place; (3) Uterus: embryo & foetus grow in it; (4) Vagina: discharge menstrual flow, receive spermatozoa, as a part of the birth canal. female sexual hormone: estrogens & progestogens

Phases in the life of a female: Childhood Puberty Sexual maturity Menopause ( or Climacterium) the genital organs undergo cyclic changes in structure and functional activity. Neurohumoral mechanism Menarche 月经初潮

OVARIES

Tunica albuginea Cortex Surface epi. Medulla

Ovarian structure: Surface epithelium: simple cuboidal epi. Tunica albuginea: D.C.T ; Cortex: thick Stroma: dense c.t., rich in reticular fibers & spindle-shaped stroma cells; Follicles & corpora lutea: in various stages of development & regression; Medulla: loose c.t. w/ lymphatic & b.v., N.

Ovarian follicle Oogenesis: Oocytes→Ova Oocyte Follicular cells Oogonium Primary oocyte Secondary oocyte Ovum Ovarian follicle Oocyte Follicular cells Oocytes: developing gametes, Ova: mature gametes.

Undergo 4 phases: I. Follicle development Primordial follicle Primary follicles Secondary follicle I. Follicle development Undergo 4 phases: Primordial follicle Primary follicle Secondary or antral follicle Mature or Graafian follicle

A B C D E

1.primordial follicle primary oocyte + a layer of squamous follicular cells. primary oocyte: round, with a large, pale-staining spherical nucleus & a prominent nucleolus. 0.3-0.4 million (before puberty) in the pairs of ovary.

2. primary follicle Primordial follicle Primary follicle From beginning of puberty, Due to the stimulation of FSH. l5-20 primordial follicles continue their maturation w/ each menstrual cycle. Only one of them reaches full maturity & gets to ovulation, the others degenerate.

2. primary follicle The main changes are: Primary oocyte: grow up (b) Follicular cells: Squamous cuboidal Simple layer several layers (granulosa cells); (c) Zona pellucida appears; (d) Theca folliculi formed From spindle stroma cells Multilaminar primary follicle Unilaminar primary follicle

3. secondary follicle ： (a) Follicular antrum: A cavity filled follicular fluid (secreted by granulosa cells & permeated from b.v.); (b) Granulosa layer: Several layers of follicular cells surrounding the antrum.

(c) Cumulus oophorus: At one side of follicular antrum Oocyte grows to D=125-150 um Corona radiata: a layer of radially columnar c. (granulosa c.) surrounding oocyte.

(d) Theca folliculi: Theca interna: rich in capillaries more cells (polygonal w/ the structures of steroid hormone-secreting cells) secrete estrogen Theca externa: less cells & more fibers.

granulosa cells primary oocyte

4. mature follicle( Graafian follicle)： 1 2 3 4 5 6 7 8 9 The follicle reaches D = l-l.5 cm & bulges on the surface of the ovary; Follicular antrum enlarges & granulosa layer becomes thinner; A very thick theca folliculi.

Primary oocytes are found in: All primordial follicles All primary follicles All secondary follicles Mature(Graafian) follicles also contain primary oocytes until hours before ovulation when meiosis Ⅰis completed

Ⅱ. Ovulation

Ovulation: 14 days before the expected onset of the next menstruation. (menstrual cycle: 28 days) Serum level of the LH reaches a peak. Secondary oocyte + zona pellucida+ corona radiata + follicular fluid are released into pelvic cavity.

Ovum is swept into oviduct via fimbriated funnel. After ovulation, ● If not fertilized, the ovum will degenerate in 24 h. ● Otherwise, the fertilized oocyte completes second division & forms a mature ovum w/ (23, X) .

Puberty Menopause Menstrual cycle(28-day cycle): 1 ovum Menarche : 12 years of age Menopause : 45-55 years of age Menstrual cycle(28-day cycle): 1 ovum During the reproductive life span: only about 400 mature ova.

corpus luteum

Ⅲ. Corpus luteum After ovulation, the ruptured follicle collapses. Stimulated by LH, the cells differentiate into the corpus luteum w/ abundant capillaries.

The main changes: (l) granulosa cells granulosa lutein cells (great number, large size & pale staining) & secrete progesterone. (2) theca interna cells theca lutein cells (smaller, more deeply staining) & secrete estrogen. (3) Both of them have the structures of steroid hormone secreting cells.

Granulosa lutein cells theca lutein cells

Development of the corpus luteum: The corpus luteum of menstruation: when the oocyte is not fertilized, it degenerates in 2 weeks. The corpus luteum of pregnancy: when the oocyte is fertilized, it continually grows up to 3-4 cm & maintains 4-6 months. It secretes estrogen (E2), progesterone (P) & relaxin (to relaxe smooth muscle cells of uterus). corpus albicans

Ⅳ. Atresia Follicles will degenerate at any stages: Primordial & primary follicle atretic follicle Secondary & early mature follicle interstitial gland (to secrete estrogen)

UTERUS

General structure: A muscular organ. The wall divides into 3 layers: endometrium myometrium perimetrium A muscular organ. The wall divides into 3 layers: endometrium (mucosa), myometrium(muscullosa), perimetrium (serosa).

I. Perimetrium : Serosa (most area) or adventitia . II. Myomerium: ◆ Thick (l2-15 mm), bundles of smooth muscles & c.t. w/ abundant b.v. ◆ During pregnancy, numbers & length (50 to 500 um) are increased by differentiation of primitive c.t. cells & by mitotic divisions of smooth muscle cells.

Ⅲ. Endometrium: Consisits of： （1）simple columnar epi. （2）laminar propria：C.T. a. uterine glands b. stroma cells c. spiral arteries

Two layers： （1）the functionalis: （2）the basalis:

cyclic changes of the endometrium: Menstruation: from puberty, functional layer sheds & bleeds in cycle, then regenerates from the basal layer. Menstrual cycle During pregnancy, functional layer proliferate & become thicker to facilitate the implantation of fertilized ovum & development of embryo & foetus.

1. Menstrual phase ( l-4 d) During the 14th day after the preceding ovulation. Corpus luteum of menstruation degenerates Serum level of E2 & P Sharply decrease Vasoconstriction of spiral A. Ischaemia & necrosis of the functional layer →Subsequently vasodilation & bleeding & shedding of the necrotic tissue.

2. Proliferative phase (5-14 d) Low levels of E2 & P stimulate FSH secreting A group of new follicles are developing & secreting E2 (follicular phase of ovary). Increasing E2 stimulates endometrium & all the endometrial structures begin to proliferate : (a) Epi. is repaired, endometrium l-3mm, stroma cells are proliferating & synthesize glycogen & collagen; (b) Glands are growing up & storing glycogen; (c) Spiral A. stretch to functional layer. ◆ Around 14th day, high levels of LH stimulate ovulation. Ovary: follicular phase

3. Secretory phase (15-28 days) After ovulation, developing corpus luteum secrete P (luteal phase of ovary), P acts on to enter the secretory phase : (a) Endometrium: thicker to 4-6 mm, stroma cells are proliferating & differentiating (If fertilization, stroma c → decidual c); (b) Glands: more coiled, glycogen accumulates at inferonucleus of glandular cells, then the glandular lumen enlarge & full of secretion; (c) Spiral A: further stretch & coil. ◆ If no fertilization takes place, corpus luteum degenerates & E2 / P↓↓, the menstrual phase begin again at the 28th day. Ovary: luteal phase

hypophysis – ovary – uterus axis LH FSH E2 P

OVIDUCTS

4 parts: Interstital part Isthmus Ampulla Infundibulum

Simple columnar epi.：secretory cells + ciliated cells mucosa Laminar propria：CT muscularis Smooth muscle，inner circular and outer longitudinal layer serosa Mucosa folds

MAMMARY GLANDS

General structure: Active state: 15-25 lobes, compound tubuloalveolar acini Active state: During pregnancy & lactation, producing milk. 1. A great mumber of secretory alveoli & duct system, divided into 12-20 lobes by c.t. 2. Alveoli consist of cuboidal cells surrounded by myoepithelial cells & b.m. Inactive state: large amount of c.t. & adipose tissue w/ few duct and small alveoli.

a. inactive state b. active state

inactive state active state

secreting state

LM: b/w oocyte & follicle cells; eosinophilic. EM: Zona pellucida: LM: b/w oocyte & follicle cells; eosinophilic. EM: both Mv. of oocyte & processes of follicle cells extend into it gap junctions are seen b/w follicle cells & b/w oocyte & follicle cells. Produced by both oocyte & follicle cells.

JUNE 17, 2008 Ovulation caught on film Can't believe scientists had such a basic human function as ovulation wrong. Just goes to show science has a lot still to learn about a woman's reproductive cycle. (And if they had this wrong, how much do they not yet know about the birth control pill's mode(s) of action?) From Sify News: A researcher associated with the Catholic University of Louvain in Brussels has accidentally captured the images showing the production of an egg inside a woman's body, something known as 'ovulation' in medical terminology. Jacques Donnez has revealed that he captured the event while preparing to carry out a partial hysterectomy on a 45-year-old woman. Observing ovulation in humans is extremely rare, and previous images have been fuzzy. "The release of the oocyte from the ovary is a crucial event in human reproduction. These pictures are clearly important to better understand the mechanism," New Scientist magazine quoted Donnez as saying. Most scientists believe that the release of an egg occurs as a sudden, explosive event. However, Donnez's pictures show it taking place over a period of at least 15 minutes. The researcher says that shortly before the egg is released, enzymes break down the tissue in the mature follicle, a fluid-filled sac on the surface of the ovary that contains the egg. He says that this prompts the formation of a reddish protrusion, and after a while a hole appears, from which the egg emerges, surrounded by support cells. Donnez says that it then enters a Fallopian tube, which carries it to the uterus....

Menstrual cycle: In the sexually-matuation stage, Hypothalamus – hypophysial – ovarian axis acts to the uterus, Menstrual cycle in average length of 28 days. 3 typical phases can be distinguished: Menstrual phase (days l-4); Proliferative phase (days 5-14); Secretory phase (days 15-28) .