Female Reproductive System

FEMALE REPRODUCTIVE SYSTEM Reproduction is a process of giving rise to offspring.

External Organs: These are collectively known as vulva. It includes1. The labia majora 2. The labia minora 3. The clitoris 4. The vestibule 5. The hymen 6. Vestibular glands Internal Organs: 1. 2. 3. 4.

Uterus Ovaries(Two) Fallopian tubes Vagina

UTERUS It is a muscular, pear shaped and hollow structure. It is partially covered by peritoneum and the cavity is lined by mucous membrane called endometrium. It is joined from sides to the fallopian tube and at the bottom it opens in vagina. Endometrium undergoes changes during menstrual cycle FUNCTIONz The fertilized ovum divides at the blastocyst stage and get implanted on the wall of uterus where it develops into growing fetus during pregnancy CERVIX Functions z Allow entry of spermatozoa z Prevent entry of infectious organisms

z

Passage of fetus during birth

OVARY It is a primary female sex organ. Each ovary has many large or small spherical or oval sac like masses of cells called as ovarian follicles or Graffian follicles. Each ovarian follicle has a large centrally placed ovum surrounded by many layers of granular cells. In a maturing follicle these cells secrete oestrogen in blood. Ovary also contains large mass of big, conical yellow cells called as corpus luteum which is formed form ruptured Graffian follicle whose ovum has been released. Cells of the corpus luteum secrete progesterone in the blood. Functions z Secrete female sex hormones 1. ESTROGEN – Helps in development of female secondary sex organs and external sex characters. 2. PROGESTERONE - controls pregnancy changes in female sex organs. z Produce ova OVARIAN HORMONES OESTROGENS FORMATION Theca cells of graafian follicle Granulosa cells of the graafian follicle Placenta TRANSPORT 95% bound to plasma proteins in blood MECHANISM OF ACTION TARGET ORGANS z Uterus z Vagina z Anterior hypothalamus z Anterior pituitary

ACTIONS • • • • •

Growth of genitalia Growth of ovaries, uterus, vagina Completion of ovarian cycle Stimulates growth of glandular epithelium Cervical mucus secretion becomes copious and watery

• Increase vaginal secretions and makes it acidic .this prevents vagina from bacterial infections • Promotes growth of external genitalia • Promotes development of secondary sexual characters in females • Feed back mechanism on gonadotrophins

Artificial oestrogen Diethylstilbestrol and ethinyloestradiaol Uses Used after menopause to control menopausal symptoms used as contraceptive pills

PROGESTERONE Source Corpus luteum Placenta Action – not bound to specific substance but has action on tissues primed by oestrogen Actions 1 Produces secretory changes in endometrium 2. Prepare endometrium for implantation of fertilized ovum

3. Increase basal body temperature 4. Decrease number of estrogen receptors 5. Inhibits ovulation by negative feed back on LHRH release from the hypothalamus Synthetic progesterone are used as contraceptive pills MENOPAUSE When menstruation ceases? Normally at 45-50 years of age Symptoms 1. Amenorrhoea 2. Hot flushes i.e. Flushing of skin of the face, neck and chest. 3. Sweating, palpitations. 4. Depression, headache 5. Osteoporosis. Small ovaries Cessation of formation of ova, corpus luteum. Cause Senile changes in ovary its function declines Ovarian cycle 1. Cyclic ovulation- release of ovum at periodic intervals 2. Approximately 10-20 follicles enlarge to become secondary follicle during each cycle under influence of FSH 3. Only one proceeds to stage of ovulation 4. At time f ovulation follicle collapses 5. After ovulation, capillaries from theca interna invade granulosa layer and is replaced by corpus luteum 6. Corpus luteum regresses if fertilization has not occurred corpus luteum grows for months if pregnancy occurs NOTE – TIMING OF OVULATION IS IMPORTANT It occurs 14 days before first day of next cycle Coitus should take place within two- three days preceding ovulation .

MENSTRUAL CYCLE The periodic discharge of bloody fluid from the uterus at regular intervals throughout life in female from puberty to menopause. NORMAL CYCLES 28- 35 DAYS Four phases 1. Menstrual phase 2. Proliferative phase 3. Ovulation phase 4. Secretory phase 1. Menstrual phase During menstrual phase, endometrium sheds and blood, mucus etc pass outs. It lasts for 3- 5 days. After this time it may be considered abnormal. If fertilization of ovum has not occurred then menstruation occurs. i.e bleeding from female genital tract Shedding of superficial part of endometrium due to spasm of spiral arteries, mainly arterial 2. Proliferative phase Day 5 – 14 In this phase proliferation of endometrium takes place. Uterine epithelium is restored to normal, endometrium becomes thicker and more vascular. Ovarian follicle is matured and secretes estrogen Cervical secretion increases and become more watery 3. Ovulatory phase 14th day Before 14 days of the start of the menstruation there is a sudden rise in FSH and LH and Graffian follicle of one ovary ruptures to liberate an ovum called as ovulation Volume of cervical mucus increases and becomes more watery 4. Secretory phase Day 15 -28 Preparation of uterus for implantation of the fertilized ovum Endometrium increases in thickness and produce abundant secretion

During this phase corpus luteum , in an ovary developed and secrete progesterone Endometrial changes - glands becomes more tortuous Spiral arteries more coiled and filled with blood. Cervical secretion becomes thick, tenacious, barrier for infectious

FEED BACK MECHANSIM HYPOTHALAMUS ↓ GnRH ANTERIOR PITUITARY ↓ LH ↓ FSH OVARY ↓ FOLLICULAR PAHSE ↓ OESTROGEN ↓ PROLIFERATIVE PHASE 1. 2. 3. 4.

LUTEAL PHASE ↓ PROGESTROGEN ↓ SECRETORY PHASE

GnRH released from hypothalamus. GnRH release is cyclic GnRH acts on anterior pituitary that releases FSH and LH FSH promotes development of follicles Increase secretion of estrogen form theca internal cells that leads to proliferative changes in endometrium. 5. OESTROGEN SURGE - - - rise in FSH concentration just before ovulation, at 12-13 - days with resultant peak in estrogen level 6. Oestrogen surge has positive feedback mechanism on on GnRH , resulting in more release of GNRH

7. GNRH induces rapid rise of LH secretion( at mid cycle) 8. Ovulation occurs 10 hours after LH peak. 9. Stimulus to ovulation depends upon FSH and LH 10. After ovulation LH and FSH concentration Falls 11. After formation of corpus luteum , concentration of progesterone increase and also level of oestrogen rises 12. Elevated oestrogen and progesterone has inhibitory effect on FSH and LH 13. Progesterone causes secretory phase of endometrium 14. If fertilization takes place implantation of fertilized of fertilized ovum. And corpus luteum grows. 15. If fertilization does not occur then corpus luteum regresses.

OOGENESIS It is the production of secondary oocytes with in ovaries. Ovaries contain oogonia, which are diploid cells. Oogonia divide and develop into larger diploid cells called primary oocytes. Primary oocyte undergoes first meiotic division to form one polar body and one secondary oocyte. The primary oocyte contains 44 chromosomes while polar body and secondary oocyte contains 22 chromosomes . Secondary oocyte then undergoes second meiotic division to form a mature oocyte. And one second polar body. The first polar body undergoes meiotic division to form two more polar bodies.