Female Reproductive System Anatomy and Physiology PDF

Female reproductive system – Anatomy and Physiology Anatomical Features of the Female Reproductive Tract The uterus has three distinct layers: endometrium (glandular lining), myometrium (muscular middle layer), and perimetrium (outer serous layer). The uterus measures approxim...

Female reproductive system – Anatomy and Physiology Anatomical Features of the Female Reproductive Tract The uterus has three distinct layers: endometrium (glandular lining), myometrium (muscular middle layer), and perimetrium (outer serous layer). The uterus measures approximately 8 cm in length, 5 cm in width, and 3 cm in thickness, positioned anteverted relative to the vagina. The cervix serves as a passage between the uterus and vagina, featuring an internal os (opening from uterine cavity) and external os (opening into vagina). Isthmus is the supra vaginal portion of cervix, the lower uterine segment. Posterior is deeper covered with peritoneum The vagina is a thin-walled tube, measuring 8-10 cm, structured normally as anteverted and antiflexed with contact walls except superiorly. Anterior fornix is shallow; anterior wall is shorter than posterior. The posterior is deep covered with peritoneum of the pouch of Dougal Ovaries are responsible for oocyte development and are structured with hilum for blood vessels, nerves, and lymphatics. The appearance of the oocyte will vary with age and stage in the monthly cycle Physiological Functions of the Female Reproductive System Oogenesis occurs within the ovarian cortex, producing a secondary haploid oocyte at ovulation, comparable to spermatogenesis. Hormones play a crucial role in regulating the ovarian cycle, controlling oocyte maturation and coordinating with the menstrual cycle. The ovarian cycle involves a sequence of phases: Follicular phase (development of follicles) and Luteal phase (formation of corpus luteum post-ovulation). Oogenesis The Ovaries: Undergoes monthly cycle in which an oocyte develops Formation of a secondary (2y) haploid (n) oocyte at ovulation which may or may not be fertilised. Similar to spermatogenesis; 1 x mitosis, 2 x meiosis Each embryonic ovary contains ~1000-2000 primordial germ cells that divide by mitosis to form around 3 million oogonia. Sequence includes mitosis (in utero), meiosis I (after puberty each month) and meiosis II (at fertilisation). Oocytes develop in ‘follicles’ with a visible sequence of follicular changes. Defined by the Follicular phase and Luteal Phase Female reproductive system – Anatomy and Physiology Oocytes develop in Follicles Follicular Stages: Primordial Primary Secondary Follicular phase Antral Corpus luteum Corpus albicans Luteal phase Marieb and Hoehn, 10th Ed. Oogenesis Process Primordial germ cells divide to yield oogonia, leading to primary oocytes that become arrested in prophase I of meiosis until ovulation. Monthly cycles after puberty result in the maturation of primary follicles into secondary (Graafian) follicles, with ovulation typically occurring around day 14 of a 28-day cycle. Polar bodies disintegrate during the meiosis process, with fertilization completing meiosis II. Primordial – 1y oocyte, follicular cells Primary – 1y oocyte, zone pellucida, theca interna and externa granulosa cells Secondary – 1y oocyte Graddin – 2y oocyte, atrum, follicular fluid, corona radiata Corpus luteum – endocrine secretion of progesterone Corpus albicans – degenerating corpus lutenum Ovulation The rupture of the gradian follicle and release of 2y oocyte into the pelvic cavity and it is usually just one oocyte Happens around day 14 of the 28 day cycle caused by hormonal changes leading to the LH stage A combination of hormonal changes and enzymatic effects take place such as increased volume and pressure of the follicular fluid, enzymatic proteolysis of follicular wall The remains follicle forms the corpus luteum Endocrine regulation of ovarian function Ovaries are responsible for the oogenesis and cyclic synthesis of steroidal oestrogens and progesterone Principal events of the menstrual cycle in the uterus can be correlated with those of the ovarian cycle and changes in the endometrium Female reproductive system – Anatomy and Physiology Ovarian cycle Ovarian Cycle Monthly series of events associated with the maturation of an ovum Hypothalamus Synthesis and secretion of oestrogens from theca / granulosa cells GnRH Synthesis and secretion of progesterone from the corpus luteum Ant. Pituitary Gonadotrophs Regulated by anterior pituitary gonadotrophins, LH and FSH (FSH) LH Oestrogen/ Gonad Testosterone Progesterone Follicle stimulating hormone Stimulates the growth of granulosa cells and initial development of the primary ovarian follicles Stimulates the synthesis and secretion of oestrogen and inhibin from granulosa cells (negative feedback) Up regulates LH receptors in granulosa cells Many follicles may begin to mature during each cycle but only one dominant follicle will mature to a secondary follicle Luteinising hormone (LH) The dominant follicle that will ovulate is that which most rapidly acquires LH receptors, therefore reacts with the lH concs Lh stimulates later development of ovarian follicles A surge of LH induces ovulation – peak day 13-14 Stimulates the production of oestrogen via theca cells Stimulates the production of progesterone by CL Mullerian hormone – produced by granulosa cells. Prevents development of surrounding primary follicles Female reproductive system – Anatomy and Physiology the ovarian cycle The Ovarian Cycle +ve Feedback Tortora: Principles of human anatomy and physiology. 11th Edition Feedback Tortora: Principles of human anatomy and physiology. Principles of Human Anatomy 1 11th Edition and Physiology, 11e Female reproductive system – Anatomy and Physiology Menstrual Cycle Series of change in the endometrium of the non – pregnant female Regulated by ovarian steroids Each month the endometrium are prepared to nourish and receive fertilised ovum If no fertilisation happens, the stratum functionalis is shed (menstruation) Hormonal Regulation GnRH from the hypothalamus stimulates the anterior pituitary to release LH and FSH, regulating ovarian steroid hormone synthesis. FSH stimulates granulosa cell growth and estrogen production, while LH surge triggers ovulation and corpus luteum development. Anti Mullerian Hormone (AMH) regulates follicle development by inhibiting surrounding primary follicles. Menstrual Cycle Stages The menstrual cycle consists of shedding of the stratum functionalis (menstruation), proliferative phase (repair and proliferation under estrogen), and secretory phase (preparation for potential implantation due to progesterone). If fertilization doesn't occur, the corpus luteum atrophies, leading to a decline in progesterone and shedding of the uterine lining. Ovarian steroids regulate the cycle 1st Menstrual Stage: shedding of stratum functionalis if CL progesterone is lost Proliferative 2nd Stage: Ovarian oestrogens promote proliferation and repair of Strat. Functionalis. Secretory 3rd Stage: Oestrogen and progesterone from the CL promotes uterine receptivity and glandular secretions. If hCG from the placenta does not take over the role of LH then the CL atrophies Female reproductive system – Anatomy and Physiology Menopause and Related Clinical Issues Peak reproductive ability occurs in the 20s; most women stop ovulating by mid-40s, averaging menopause around age 50. Ovaries become less response to gonadotropin signals Once ovulation ceases this is called the menopause Decreased oestrogen leads to symptoms such as vaginal dryness, hot flushes, and increased risk of urinary tract infections (UTIs). Treatment options include hormone replacement therapy (HRT) for symptom relief. Common Clinical Problems Dysmenorrhoea (painful menstruation), amenorrhoea (absence of menstruation), endometriosis (growth of endometrial tissue outside the uterus), and polycystic ovary syndrome (PCOS) signify various reproductive health issues. Female reproductive system – Anatomy and Physiology Amenorrhoea Strenuous physical activity that can delay menarche or disrupt normal menstrual cycle Bladder Urethra Uterus Ovary Vagina Rectum