6 THE FEMALE REPRODUCTIVE SYSTEM.pdf

THE FEMALE REPRODUCTIVE SYSTEM internal part of the ovary, consists of loose connective tissue and blood vessels entering through hilum from mesenteries.  TUNICA ALBUGINEA CORTEX MEDULLA  PRIMORDIAL FOLICLE FOLLICULAR CELLS PRIMARY OOCYTE BASEMENT MEMBRANE FSH-Follic...

THE FEMALE REPRODUCTIVE SYSTEM internal part of the ovary, consists of loose connective tissue and blood vessels entering through hilum from mesenteries.  TUNICA ALBUGINEA CORTEX MEDULLA  PRIMORDIAL FOLICLE FOLLICULAR CELLS PRIMARY OOCYTE BASEMENT MEMBRANE FSH-Follicle stimulating hormone With growth of oocyte it started secreting zona pellucida. SECONDARY FOLLICLE or MULTILAMINAR PRIMARY FOLLICLE PRIMARY OOCYTE ZONA PELLUCIDA GRANULOSA CELLS BASEMENT MEMBRANE THECA FOLLICULI SECONDARY/ ANTRAL FOLLICLE or TERTIARY FOLLICLE Further proliferation of follicular cells forming multilaminar primary follicle- stratum granulosum. With growth of oocyte it started secreting zona pellucida. With further growth surrounding connective tissue stroal cells specialize forming a sheath “Theca folliculi”. Fibroblasts outside the growing follicles have developed as a steroid secreting theca interna (TI). SECONDARY/ ANTRAL FOLLICLE or TERTIARY FOLLICLE SECONDARY/ ANTRAL FOLLICLE or TERTIARY FOLLICLE SECONDARY / ANTRAL FOLLICLE 1. SECONDARY FOLLICLE (MULTILAMINAR PRIMARY FOLLICLE) 2. TERTIARY FOLLICLE(SECONDARY/ ANTRAL FOLLICLE) 1 2 When size of growing follicle reaches 10 mm called Graafian follicle  MATURE FOLLICLE (GRAAFIAN FOLLICLE) ZONA PELLUCIDA BASEMENT MEMBRANE CORONA RADIATA SECONDARY OOCYTE IN SECOND MEIOTIC METAPHASES CUMULUS OOPHORUS GRANULOSA CELLS ANTRUM FOLLICULI THECA FOLLICULI: 1. THECA INTERNA 2. THECA EXTERNA  ZONA PELLUCIDA CORONA RADIATA GRANULOSA CELLS SECONDARY OOCYTE IN ANTRUM FOLLICULI SECOND MEIOTIC METAPHASES CUMULUS OOPHORUS BASEMENT MEMBRANE THECA FOLLICULI : THECA INTERNA ANTRUM FOLLICULI BASEMENT MEMBRANE ZONA PELLUCIDA CORONA RADIATA SECONDARY OOCYTE IN SECOND MEIOTIC METAPHASES GRANULOSA CELLS CUMULUS OOPHORUS  FOLLICULAR ATRESIA Most ovarian follicles undergo the degenerative process called ATRESIA, in which follicular cells and oocytes die and are disposed of by phagocytic cells. Follicles at any stage of development, including nearly mature follicles, may become atretic. Atresia is characterized by apoptosis of follicle or granulosa cells and autolysis of the oocyte, collapse of the zona pellucida, with macrophages entering the degenerating structure to clean up debris. Although follicular atresia takes place from before birth until a few years after menopause, it is most prominent just after birth, when levels of maternal hormones decline rapidly, and during both puberty and pregnancy, when qualitative and quantitative hormonal changes occur again.  UNILAMINAR PRIMARY PIRIMORDIAL FOLLICLE MULTILAMINAR or PRIMARY FOLLICLE FOLLICLE PRIMARY or FOLLICLE SECONDARY FOLLICLE SECONDARY/ ANTRAL FOLLICLE or TERTIARY FOLLICLE OVARIAN MATURE FOLLICLE (GRAAFIAN FOLLICLE) Oogenesis begins in the female fetus, with primary oocytes arresting at prophase I in primordial follicles, which remain inactive during childhood. At puberty, a population of primordial follicles begins to develop each month. Typically one per month produces a female gamete (a secondary oocyte).  BEFORE BIRTH (EMBRYONIC AND FETAL PERIOD) Oogonia are diploid cells (containing 23 pairs of chromosomes, or 46 total) that are the origin of oocytes. Mitotic divisions of oogonia produce primary oocytes, which are diploid cells. Primary oocytes start the proces of meiosis but are arrested in prophase I. CHILDHOOD Ovary is inactive. It houses primordial follicles. Some atresia of primordial follicles occurs MONTHLY, FROM PUBERTY TO MENOPAUSE Up to approximately 20 primordial follicles mature into primary follicles every month. Some primary follicles mature into secondary follicles. Primary follicles that do not mature undergo atresia. Typically only one secondary follicle matures into a vesicular follicle, where the primary oocyte completes the first meiotic division to produce a polar body and a secondary oocyte. The secondary oocyte is a haploid cell (containing 23 chromosomes only) that is arrested in the second meiotic metaphase. If the secondary oocyte is fertilized, it completes the second meiotic division and becomes an ovum. If the secondary oocyte is not fertilized, it degenerates  OVULATION is the hormone-stimulated process by which the oocyte is released from the ovary. Ovulation normally occurs midway through the menstrual cycle, that is, around the 14th day of a typical 28-day cycle. In the hours before ovulation, the mature dominant follicle bulging against the tunica albuginea develops a translucent ischemic area, the stigma, in which tissue compaction has blocked blood flow. In humans usually only one oocyte is liberated during each cycle, but sometimes either no oocyte or two or more simultaneous oocytes may be expelled. (LH- lutropin) FSH-Follicle stimulating hormone After ovulation, the portion of the follicle left behind forms the corpus luteum, which then degenerates into the CORPUS ALBICANS (this is the scar of connective tissue). It contains mostly collagen, with few fibroblasts or other cells, and gradually becomes very small and lost in the ovarian stroma. Involution of the corpus luteum does not involve atresia. CORPUS ALBICANS  OVARIAN CYCLE THREE PHASES OF OVARIAN CYCLE : 1. FOLLICULAR PHASE Development of primordial follicle – Mature follicle. 2. OVULATORY PHASE Release of oocyte from mature follicle and capture by oviducts 3. LUTEAL PHASE Residual follicular cell folds and becomes part of Corpus Luteum  OVIDUCT SIMPLE COLUMNAR EPITHELUM TUNICA MUCOSA LAMINA PROPRIA TUNICA MUCULARIS TUNICA SEROSA BLOOD VESSELS  UTERUS 1. FUNCTIONAL LAYER 2. BASAL LAYER LAMINA PROPRIA SIMPLE COLUMNAR EPITHELIUM ENDOMETRIUM UTERINE GLANDS 1. SUBMUCOSAL STRATUM - longitudinal 2. VASCULAR STRATUM 3 SUPRA VASCULAR STRATUM - longitudinal MYOMETRIUM PERIMETRIUM  Under stimulus of estrogens & progesterone endometrium undergo cyclic structure modification DURATION = 28 days PUBERTY MENOPAUSE HISTOLOGICAL CHANGES DURING IN THE UTERINE CYCLE A substantial portion of the endometrium (functionalis layer) is shed at menstruation leaving a layer (basalis of the endometrium) that undergoes resurfacing growth and maturation in preparation for implantation. The structural and functional changes involved are driven by a cytokines and ovarian hormones with estrogen and progesterone playing a major role. The uterine cycle starts with menstruation and is typically described as three phases: PROLIFERATIVE PHASE (days 5-14) - driven by estrogen (and progesterone) SECRETORY PHASE (days 15-28) - dependent on progesterone MENSTRUAL PHASE (days 1-4) - initiated by ischemia After menstrual phase Coincides with ovarian follicles development (estrogens) Regeneration of endometrium day 14, fully restored: ❖ surface epithelium ❖ lamina propria ❖ coiled arteries ❖ uterine glands : simple columnar epithelium, straight tubule, narrow lumens Begins after ovulation Depends on Corpus Luteum Secretions (progesterone) Uterine glands: coiled & branched, accumulation of glycogen-dilate the lumen Compaction of functionalis (edema and secretory product); Prepared to receive zygote When no fertilization Corpus Luteum degenerates drop in progesterone & estrogens Coiled arteries constrict occurs ischemia & necrosis of functionalis layer Rupture of arteries leads to hemorrhagic Shedding of functional layer, Basal layer remain viable restore functional layer Uterine Endometrium  UTERINE BODY SIMPLE COLUMNAR EPITHELIUM UTERINE GLANDS ENDOMETRIUM MYOMETRIUM THE CERVIX SIMPLE COLUMNAR EPITHELIUM STRATIFIED SQUAMOUS EPITHELIUM THE CERVIX SIMPLE COLUMNAR EPITHELIUM UTERINE GLANDS VAGINA STRATIFIED SQUAMOUS EPITHELIUM TUNICA MUCOSA TUNICA MUSCULARIS VAGINA STRATIFIED SQUAMOUS EPITHELIUM LAMINA PROPRIA TUNICA MUCOSA CIRCULAR MUSCLE LAYER TUNICA MUSCULARIS LONGITUDINAL MUSCLE LAYER TUNICA ADVENTITIA