🫀Anatomy and Physiology II Unit 11 – Female Reproductive System Anatomy & Physiology

Key Anatomical Structures

• Ovaries produce female gametes (oocytes) and secrete hormones (estrogen and progesterone)
• Fallopian tubes transport oocytes from the ovaries to the uterus and serve as the site of fertilization
  • Divided into infundibulum, ampulla, and isthmus regions
• Uterus is a muscular organ that supports the developing fetus during pregnancy
  • Consists of the fundus, body, and cervix
  • Endometrium lines the uterine cavity and undergoes cyclic changes during the menstrual cycle
• Cervix connects the uterus to the vagina and acts as a barrier to prevent infections
• Vagina is an elastic, muscular canal that serves as the birth canal and receives the penis during intercourse
• External genitalia include the labia majora, labia minora, clitoris, and vestibular glands (Bartholin's glands)

Hormones and Endocrine Control

• Hypothalamus releases gonadotropin-releasing hormone (GnRH) to stimulate the anterior pituitary gland
• Anterior pituitary gland secretes follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
  • FSH stimulates follicle development and estrogen production in the ovaries
  • LH triggers ovulation and promotes progesterone production by the corpus luteum
• Ovaries produce estrogen and progesterone, which regulate the menstrual cycle and prepare the uterus for pregnancy
  • Estrogen promotes the growth and maintenance of female reproductive tissues and secondary sexual characteristics
  • Progesterone prepares the endometrium for implantation and maintains pregnancy
• Negative feedback loops regulate hormone levels throughout the menstrual cycle
• Positive feedback loop between estrogen and LH triggers ovulation

Ovarian and Menstrual Cycles

• Ovarian cycle consists of follicular phase, ovulation, and luteal phase
  • Follicular phase involves the growth and development of ovarian follicles under the influence of FSH
  • Ovulation occurs when a mature follicle ruptures and releases an oocyte, triggered by a surge in LH
  • Luteal phase involves the formation of the corpus luteum, which secretes progesterone to prepare the endometrium for implantation
• Menstrual cycle is divided into menstrual, proliferative, and secretory phases
  • Menstrual phase involves the shedding of the endometrium if fertilization does not occur
  • Proliferative phase is characterized by the growth and thickening of the endometrium under the influence of estrogen
  • Secretory phase involves the preparation of the endometrium for implantation, driven by progesterone from the corpus luteum
• Cycles are typically 28 days long but can vary between individuals

Oogenesis and Follicular Development

• Oogenesis is the process of producing mature female gametes (oocytes)
  • Begins during fetal development and is arrested at prophase I until puberty
  • Primordial germ cells differentiate into oogonia, which undergo mitosis to form primary oocytes
• Follicular development occurs in the ovaries and is regulated by FSH and LH
  • Primordial follicles contain primary oocytes surrounded by a single layer of granulosa cells
  • Primary follicles have a multilayered granulosa cell wall and a theca cell layer
  • Secondary follicles contain a fluid-filled antrum and continue to grow
  • Graafian (preovulatory) follicle is the mature stage, ready for ovulation
• Atresia is the degeneration of follicles that do not reach maturity, occurring throughout a woman's reproductive life

Fertilization and Early Development

• Fertilization occurs in the ampulla of the fallopian tube when a sperm penetrates the oocyte
  • Acrosomal enzymes help the sperm penetrate the zona pellucida
  • Cortical reaction prevents polyspermy by modifying the zona pellucida
• Zygote undergoes cleavage, forming a morula and then a blastocyst
  • Inner cell mass gives rise to the embryo, while the trophoblast forms extraembryonic structures
• Implantation occurs when the blastocyst attaches to the endometrium, typically 6-7 days after fertilization
  • Trophoblast cells differentiate into syncytiotrophoblast and cytotrophoblast, which invade the endometrium
• Placenta develops from the trophoblast and connects the fetus to the maternal circulation
  • Allows for nutrient and gas exchange, waste removal, and hormone production
• Embryonic period (weeks 3-8) involves the formation of major organ systems
• Fetal period (week 9 until birth) is characterized by growth and maturation of organs and tissues

Common Disorders and Diseases

• Polycystic ovary syndrome (PCOS) is characterized by irregular menstrual cycles, hyperandrogenism, and polycystic ovaries
  • Can lead to infertility, metabolic disorders, and cardiovascular disease
• Endometriosis occurs when endometrial tissue grows outside the uterus, causing pain and infertility
• Uterine fibroids are benign tumors that develop in the uterine muscle, potentially causing heavy menstrual bleeding and pelvic pain
• Cervical cancer is often caused by human papillomavirus (HPV) infection and can be detected through regular Pap smears
• Sexually transmitted infections (STIs) such as chlamydia, gonorrhea, and herpes can affect the female reproductive system and cause complications
• Menopause is the permanent cessation of menstrual cycles, typically occurring in the late 40s to early 50s
  • Associated with decreased estrogen levels and symptoms such as hot flashes, vaginal dryness, and osteoporosis

Clinical Applications and Diagnostics

• Pelvic exam involves visual inspection and palpation of the external and internal reproductive organs
  • Pap smear is performed to screen for cervical cancer by collecting cells from the cervix
• Transvaginal ultrasound uses high-frequency sound waves to visualize the reproductive organs
  • Helps diagnose conditions such as ovarian cysts, uterine fibroids, and ectopic pregnancy
• Hysteroscopy involves inserting a thin, lighted camera through the cervix to examine the uterine cavity
• Laparoscopy is a minimally invasive surgical procedure that allows visualization of the pelvic organs
  • Used for diagnosing and treating conditions such as endometriosis and ectopic pregnancy
• Hormonal assays measure levels of reproductive hormones (FSH, LH, estrogen, progesterone) in blood or urine samples
  • Help evaluate ovarian function, menstrual disorders, and infertility
• Genetic testing can identify mutations associated with hereditary cancers (BRCA1/BRCA2) and other reproductive disorders

Connections to Other Body Systems

• Hypothalamic-pituitary-gonadal axis integrates the endocrine system with the reproductive system
  • Hormonal feedback loops regulate reproductive function and maintain homeostasis
• Cardiovascular system supplies blood to the reproductive organs and is affected by hormonal changes
  • Estrogen has cardioprotective effects, while menopause increases the risk of cardiovascular disease
• Immune system plays a role in protecting the reproductive tract from infections and in regulating implantation and pregnancy
  • Shift towards immunotolerance during pregnancy to prevent rejection of the fetus
• Skeletal system is influenced by reproductive hormones, particularly estrogen
  • Estrogen helps maintain bone density, while decreased levels after menopause can lead to osteoporosis
• Reproductive disorders can impact mental health and quality of life
  • Conditions such as PCOS, endometriosis, and infertility can cause emotional distress and psychological challenges
• Pregnancy and childbirth involve significant changes in multiple body systems
  • Adaptations in the cardiovascular, respiratory, and digestive systems support fetal development and prepare for labor and delivery