1.  Obstetrics & Gynecology Week 1 Female anatomy, normal menstrual cycle

2. Female Anatomy  Terms to know:  Vulva: external genital organs  Consists of: mons pubis, labia majora, labia minora, hymen, clitoris, vestibule, urethra, Skene’s glands, Bartholin’s glands, vestibular bulbs

3. Female Anatomy

4.  Labia majora: cutaneous folds of adipose and fibrous tissue  Outer surface covered in hair follicles  Inner surface has sebaceous glands  Both have sweat glands  Homologous to scrotum in male  Size related to fat content; atrophy after menopause

5. Female Anatomy Labia minora are cutaneous folds located between labia majora Dense connective tissue with erectile tissue and elastic fibers Sebaceous glands but no hair follicles (as are the breasts) Homologous to penile urethra Relatively more prominent in children and postmenopausal women

6. Female Anatomy  Clitoris is a short, cylindrical erectile organ at superior portion of vestibule (area within labia minora)  Distal 1/3 rd is glans, contains many nerve endings  Homologous to penis in male

7. Female anatomy  Urethra is a conduit for urine from the urinary bladder to the vestibule  Approximately 3.5 to 5 cm in length (male urethra is 17.5 cm in length  Length is one of the factors in frequency of UTIs in females vs. males

8. Female Anatomy  Skene’s glands: branched, tubular glands adjacent to distal urethra  Secrete lubrication  Highly variable anatomy  Homologous to prostate in males

9. Female Anatomy

10.  Bartholin’s glands are vulvovaginal glands located beneath fascia, 4 and 8 o’clock  Ducts open into a groove between labia minora and hymen  Secrete mucus for vaginal lubrication  Homologous to Cowper’s glands in men  Both Bartholin’s and Skene’s glands may become infected

11. Female Anatomy  Introitus: vaginal opening (technically any opening into a cavity or canal)  Anus: rectal outlet or opening

12. Female Anatomy  Internal anatomy terms to know:  Vagina, cervix, uterus, broad ligament, ovaries, fallopian tubes, bladder, rectum  Broad ligament is a thin, double layer of peritoneum that envelopes Fallopian tubes, ovarian and round ligaments, uterus, ovarian and uterine arteries and veins

13. Female Anatomy

16. Normal Stages of Development  Pre-pubertal changes  Adrenarche: maturation of adrenal cortex  Ages 6-10 average  Development of pubic and axillary hair  Sweat composition changes (body odor)  Skin oiliness and acne

17. Normal stages of Development  Pre- pubertal changes:  Gonadarche: gradual maturation of interactions between GnRH (gonadotropin- releasing hormone), pituitary hormones, and ovaries  Earliest gonadal changes in puberty  Growth of gonads (ovaries and testes), increase in sex steroid hormones in response to pituitary hormones

18. Normal stages of development  Puberty: sequence of events by which a child reaches sexual maturity  Early puberty: decreased sensitivity of hypothalamus to sex hormones  Development of secondary sex characteristics without ovulation  May also be independent of HPO axis

19. Puberty Tanner Stages I-V pubic hair and breast development

20. Normal Stages of Development  Thelarchy: postnatal breast development  60% of the time this is the first stage of puberty  Breast bud development occurs on average 2 years prior to menarche

21. Normal Stages of Development  Menarche: onset of menstruation, which is a bloody vaginal discharge that occurs as a result of endometrial shedding after ovulation, when fertilization has not occurred  In US, average age 12.5 years  Time influenced by environment, genetics, nutritional status

22. Normal Stages of Development  Menarche:  Critical weight, body fat % needed  Obesity- earlier menarche  Malnourishment or athletes- delayed menarche During adolescence/ menarche, more common to have annovulatory cycles, leading to irregular or heavy bleeding It is possible for ovulation to occur prior to or after menarche

23. Normal Stages of Development  Menarche:  Ovaries secrete estrogen in response to pituitary hormones  Pituitary hormones released by stimulation from GnRH from hypothalamus  Effects: growth in stature, breast growth, increase in adipose tissue, pelvic widening

24. Menstruation  Hormones involved: GnRH: gonadotropin- releasing hormone  Released by hypothalamus in pulsatile manner  Acts upon pituitary LH: Leutinizing hormone  Released by anterior pituitary  Acts upon ovary: Tells theca cells to make steroid hormones Induces “leutinization” of granulosa cells– make progesterone

25. Menstruation  Hormones involved (cont.)  FSH: Follicle stimulating hormone  Secreted by anterior pituitary  Acts on granulosa cells of ovary to stimulate follicular growth  Estrogen (E1/E2/E3)  Secreted by ovarian follicle  Progesterone  Secreted by ovarian corpus luteum

26. Menstruation  Hypothalamic-pituitary- ovarian axis:  Refers to interactions between hormones secreted by hypothalamus, pituitary, and ovaries  Positive and negative feedback interactions  Separate from HPA (adrenal) and HPT (thyroid) axes, although entire endocrine system interconnected

27. Hypothalamus-Pituitary-Ovaries

28. Hypothalamus- pituitary-ovary

29. Hypothalamus and pituitary glands

30. Anterior Pituitary

32. Menstruation  Cyclic vaginal discharge of sloughed endometrium (lining of uterus)  Normal cycle considered between 25-36 days  Only 10-15% of women have exact 28 day cycle (moon cycle)  Average of 130mL of blood loss  Pads/tampons absorb approx. 20-30mL

33. Menstrual Cycle  Follicular/ pre-ovulatory phase  Variable in duration (average 14 days)  First few days: slight increase in FSH, stimulates follicular growth  One growing follicle recruited for ovulation, starts producing estrogen  LH slowly rising

34. Menstrual Cycle  Follicular phase (cont.)  Estrogen levels peak, produces positive feedback on LH  LH levels surge, resulting in ovulation (the release of ovum from the follicle)  Rising estrogen levels inhibit FSH  Progesterone levels rise  Endometrium thickens with rising E levels  Increase in cervical mucus

35. Menstrual Cycle  Ovulatory phase  Begins with LH surge  LH released in pulses for about 36-48 h  Ovum released from follicle 16-32 h after LH surge  External cervical os opens from 1 to 3mm in diameter  Elastic cervical mucus forms “superhighway” for sperm

36. Menstrual Cycle  Luteal/ post-ovulatory phase  Follicle reorganizes, becomes corpus luteum  Functional life of corpus luteum is 14 days, less variation in duration of this phase  Corpus luteum secretes progesterone, which supports process of implantation of fertilized ovum  FSH and LH levels are low

37. Menstrual Cycle  Luteal phase  Effects of progesterone:  Rise in basal body temperature  Thickening, loss of elasticity of cervical mucus

38. Cyclic changes in hormones, ovarian folliles, and endometrium

39. Ovarian cycle