Female Reproductive Physiology Before Pregnancy Dr Hazrat Bilal

Female Reproductive Physiology Before Pregnancy Dr. Hazrat Bilal Malakandi DPT, IPM&R KMU

Female Reproductive Physiology • Ovaries – Contains primordial follicles – ovum surrounded by a single layer of granulosa cells is called primordial follicle. – Synthesizes and secretes sex hormones (estrogen and progesterone). • Fallopian tubules – Egg transportation from ovary to uterus (fertilization usually takes place here). • Uterus – To house and nourish developing human.

• Reproduction begins with development of ova in the ovaries. • In the middle of each ovarian cycle a single ovum is expelled from an ovarian follicle into the peritoneum near the mouth of fallopian tubes. • This ovum then passes through one of the fallopian tubes into the uterus ; if it has been fertilized by a sperm, it implants in the uterus, where it developed into the fetus, a placenta and fetal membrane n eventually into a body.

Primordial cells (Germ Cells) • Development (In fetus) – Epithelium of germinal ridges germinal epithelium primordial ova migrate into ovarian cortex collects a layer of spindle cells around it from stroma (supporting tissue of the ovary) granulosa cells primordial follicle still immature requiring two more cell divisions before ferlization Note: Only 450 out of 0. 3 -0. 4 million primordial follicles develop into garafian follicles during sexual life of women from 13 to 50 years of age, while the other degenerate and become atretic.

Female hormone system • Gonadotropin Releasing Hormone (Gn. RH) released by the hypothalamus • Follicle Stimulating Hormones (FSH) & Luteinizing Hormone (LH) both are secreted by the ant. Pituitary gland in response to the release of Gn. RH. • Estrogen and Progesterone secreted by the ovary in response to the two female sex hormones from anterior pituitary gland.

Ovarian cycle • Rhythmic cyclic changes in ovaries and its secretions are called ovarian cycle. • Period – 28 days (20 to 45 days) • Phases 3 1. Follicular (Pre-ovulatory ) Phase 2. Ovulation Phase 3. Luteal (Post-ovulatory ) Phase

1. Follicular (Pre-ovulatory) Phase • Hormones responsible – FSH and LH from ant. Pituitary gland. • Stages of development of garafian follicle – Primordial follicle Primary Follicle (under influence of FSH (mostly) & LH) vesicular follicle Mature Garafian Follicle

Cont …. Structure of Graafian Follicle a. Theca divided into two i. Theca interna and granulosa cells secrete estrogen ii. Theca externa forms capsule of the follicle b. Cumulus ophorus surrounds ovum c. Antrum contains follicular fluid & estradiol.

2. Ovulation Phase • It is a process of rupture of mature Graafian follicle to set free ovum into peritoneal cavity near mouth of fallopian tube. • Time – Ovulation occurs 14 days after onset of menstruation (when period is of 28 days) • Hormones responsible – LH from ant. Pituitary gland.

Cont … Mechanism • LH causes progesterone secretion by theca interna and granulosa cells that causes a. Theca externa to secrete proteolytic enzymes dissolve the capsular wall b. Rapid growth of new blood vessels in follicle wall and secretion of prostaglandins by the follicular tissue vasodilation. c. Plasma transudute into follicle swell follicle rupture of stigma ovum released.

Luteal (Post-ovulatory) • After ovulation Graafian follicle converts into corpus luteum, which is a yellowish mass of lutein cells filled with lipid inclusions luteinization total mass of cells is called corpus • Hormone responsible – LH & Human chorionic gonadotropin

Cont … Structure of corpus luteum • Lutien cells secrete progesterone and small amounts of estrogen, also secrete inhibin that inhibit FSH secretion. • Strands of theca cells secrete androgens (androstenedione & testosterone) much of androgen is converted by enzyme aromatase in granulosa cells into progesterone and estrogen • Well developed blood supply

Cont…. Fate of Corpus Luteum • If pregnancy occurs corpus luteum increase in size under influence of human chorionic gonadotropin of placenta secretes progesterone until end of 2 -4 months of pregnancy. • If pregnancy does not occur corpus luteum involutes and becomes replaced by connective tissue after 12 days of ovulation due to lack of FSH called corpus albicans

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