Menopause and Climacteric Phase Quiz

Female Reproductive System

• The female reproductive system is more complex than the male system because it serves more purposes, including producing and delivering gametes, providing nutrition and a safe harbor for fetal development, giving birth, and nourishing the infant.
• The female system is more cyclic, and hormones are secreted in a more complex sequence than in males.
• The genitalia include both internal and external parts. Internal genitalia include the ovaries, uterine tubes, uterus, and vagina. External genitalia include the clitoris, labia minora, labia majora, and the perineum, which contains the primary sex organs and other internal and external genitalia.
• The ovaries are the primary sex organs, producing egg cells (ova) and sex hormones.
• Ovaries are almond-shaped, nestled in the ovarian fossa of the posterior pelvic wall. They have a capsule, called tunica albuginea, similar to the testes' capsule, and the outer cortex contains germ cells which develop.
• The inner medulla of the ovary contains major arteries and veins, and each egg develops within its own fluid-filled follicle. The follicle bursts, releasing the egg.
• The uterine tube (oviduct) or fallopian tube is about 10 cm long and connects the ovary to the uterus. It is muscular and lined with ciliated cells, folded into longitudinal ridges.
• Fimbriae are feathery projections on the infundibulum of the uterine tube.
• The ampulla is the middle and longest part of the uterine tube.
• The isthmus is the narrower end of the uterine tube, leading toward the uterus.
• The uterus is a thick muscular chamber that opens into the roof of the vagina. It usually tilts forward over the urinary bladder. It harbors the fetus, providing nutrition, and expels the fetus at the end of development.
• The uterus is pear-shaped. Its fundus is the broad superior curvature. The body (corpus) is the middle portion, and the cylindrical inferior end is called the body/corpus.
• The cervical canal connects the uterine lumen to the vagina.
• The internal os is the superior opening of the canal into the body of the uterus, while the external os is the inferior opening into the vagina.
• The uterine wall consists of the perimetrium (external serosa layer), myometrium (middle muscular layer), and endometrium (inner mucosa). The myometrium is the primary muscular layer.
• The endometrium, the inner mucosa, consists of simple columnar epithelium, compound tubular glands, and a stroma with leukocytes, macrophages, and other cells.
• The superficial half of the endometrium is shed each menstrual period. The basal layer stays behind and regenerates a new functional layer each cycle.
• The vagina is a distensible muscular tube (8-10 cm) allowing for discharge of menstrual fluid, receipt of penis and semen, and birth. It has outer adventitia, middle muscularis, and inner mucosa layers.
• Fornices are blind-ended spaces at the top of the vagina that slightly extend beyond the cervix.
• Vaginal rugae are transverse friction ridges at the lower end of the vagina.
• Vaginal epithelium undergoes metaplasia from simple cuboidal in childhood to stratified squamous in puberty, under influence of estrogen.
• Bacteria ferment glycogen in the vagina producing acidic pH, inhibiting pathogen growth.
• External genitalia are collectively called the vulva (or pudendum).
• The mons pubis is a mound of fat over the pubic symphysis, bearing most of the pubic hair.
• The labia majora is a pair of thick skin and adipose tissue folds inferior to the mons.
• The labia minora are thin, hairless folds medial to the labia majora. The space between them forms the vestibule, containing the urethral and vaginal openings.
• The anterior margins of the labia minora form a hood-like prepuce over the clitoris.
• The clitoris is the primary center for sexual stimulation (sensory organ) with a glans, body, and crura.
• The vestibular bulbs are erectile tissues deep to the labia majora, bracketing the vagina. The greater and lesser vestibular and paraurethral glands open into the vestibule for lubrication.
• The breasts are mounds of tissue overlying the pectoralis major. They enlarge at puberty and contain very little mammary glands most of the time.
• Mammary glands develop in the breast during pregnancy and remain active in the lactating breast. They atrophy (shrink) when nursing ceases.
• The breast has a body (conical to pendulous, with nipple apex) and axillary tail (extension toward armpit).
• Lymphatics in the axillary tail, are important as a route for breast cancer metastasis.
• The nipple has capillaries and nerves close to the surface, making this zone sensitive. Sensory nerve fibers of the areola trigger a milk ejection reflex in response to infant nursing.
• Areolar glands (Montgomery glands) are intermediate between sweat glands and mammary glands. Secretion protects the nipple. Their smooth muscle fibers contract in response to cold, touch, or sexual arousal.
• The nonlactating breast, consists mostly of adipose and collagenous tissue.
• Breast size is determined by the amount of adipose tissue.
• Suspensory ligaments (Coopers' ligaments) attach the breast to the dermis and fascia of the overlying pectoralis major.
• Mammary ducts branch through their fibrous stroma and converge on the nipple.
• The ducts end in sacs called acini surrounded by cells. 
• Puberty begins at age 8-10 in most girls in the United States, triggered by rising GnRH levels.
• GnRH stimulates the anterior pituitary to secrete FSH and LH.
• FSH stimulates ovarian follicles to secrete estrogen, progesterone, inhibin, and a small amount of androgen. Estrogens are feminizing hormones with widespread effects on the body (estrone is most abundant, estriol and others).
• At least 17% body fat is needed for the first menstrual period, with nutrition improving onset times to 12 years old in some cases. 
• Leptin stimulates gonadotropin secretion; if body fat and leptin levels drop too low, gonadotropin secretion declines and menstruation might cease, typically when body fat drops below 22%.
• Estradiol stimulates many changes in puberty, including vaginal metaplasia, growth of ovaries and secondary sex organs, hormone secretion increases in height and widening of the pelvis, stimulates fat deposition, and thickens the skin. (Girls' skin is still thinner, softer, and warmer than boys').
• Estradiol primarily acts on the uterus, preparing it for possible pregnancy.
• Estrogens and progesterone suppress FSH and LH secretion, through negative feedback.
• Inhibin selectively suppresses FSH secretion.
• Hormones are secreted in a distinctive cyclic sequence.
• The reproductive cycle is the sequence of events from fertilization to giving birth, returning to fertility.
• The sexual cycle is the cyclical events that recur monthly when pregnancy does not intervene. The sexual cycle consists of two interconnected cycles. The ovarian cycle involves events in the ovaries, and the menstrual cycle involves parallel changes in the uterus.
• Oogenesis is egg production (haploid gametes) through meiosis. This is a distinctly cyclical event, releasing one egg each month. Cyclic changes in hormone secretion, and histological structure of the ovaries and uterus, accompanies oogenesis.
• Embryonic development of the ovary transforms into primary oocytes; during early meiosis I, most degenerate (atresia).
• By puberty, approximately 200,000 oocytes remain, with a lifetime egg capacity of probably only 480 ovulations.
• Egg development resumes in adolescence; FSH stimulates monthly cohorts to complete meiosis I. During meiosis I, an oocyte divides into two haploid daughter cells.
• Secondary oocytes are the large daughter cells resulting from meiosis I.
• First polar bodies are the smaller cells, which disintegrate, discarding extra sets of haploid chromosomes.
• Secondary oocytes proceed as far as metaphase II, arresting until after ovulation.
• If not fertilized, the secondary oocyte dies and never finishes meiosis.
• If fertilized, it completes meiosis II and casts off a second polar body; the chromosomes of the large remaining egg unite with those of the sperm.
• Hormones of the hypothalamus regulate the pituitary gland.
• Pituitary hormones regulate the ovaries and ovaries secrete hormones that regulate the uterus (basic hierarchy of hormonal control). Hypothalamus → pituitary → ovaries → uterus.
• Ovaries exert feedback control on hypothalamus and pituitary.
• The cycle begins with a two-week follicular phase.
• Menstruation occurs during the first 3-5 days; the uterus replaces lost tissue, follicles grow through mitosis.
• Ovulation occurs around day 14; the remainder of the follicle becomes the corpus luteum.
• The next two weeks are the luteal phase, during which LH stimulates endometrial secretion and thickening.
• If pregnancy does not occur, the endometrium breaks down in the last two days; menstruation begins and the cycle starts again.
• The ovarian cycle has three principle phases (follicular, ovulation, luteal).
• The uterine tube gets ready to catch the released oocyte. It swells with edema, its fimbriae envelop and caress the ovary with the woman's heartbeat's synchronous beat. Gentle currents from cilia in nearby peritoneal fluid help in movement and transport.
• Couples seeking conception or pregnancy avoidance may want to use ovulation signals. Cervical mucus changes (becoming thinner and more stretchy). Resting body temperature rises a degree or so, and Mittelschmerz (ovulation pain) occurs.
• Transformation from the ruptured follicle to the corpus luteum is controlled by LH. It triggers the growth and secretion of rising estradiol and progesterone levels. A 10-fold increase of progesterone is especially critical for the luteal phase. Progesterone plays a crucial role in preparing for pregnancy.
• LH and FSH secretion decline through the cycle. High levels of estradiol and progesterone along with inhibin from the corpus luteum have negative feedback effects on the pituitary.
• The corpus luteum begins shrinking (involution) after ovulation.
• By day 26 of ovarian involution, completing the process to create a scar where the corpus luteum used to be.
• With the declining steroid production in the ovaries, FSH rises to start the ripening of new follicles.
• Ovulation occurs in one ovary per cycle, usually alternating. Ovulated oocytes begin ripening about 290 days before birth and are recruited into cohorts (a new cohort develops, usually).
• The menstrual cycle involves a buildup of endometrium, breakdown, and discharge of the lining. It's divided into the proliferative phase, where endometrium rebuilds, the secretory phase, where it thickens, the premenstrual phase, which is the period of endometrial degeneration, and menstrual phase, involving vaginal discharge.
• Proliferative phase: endometrium rebuilds, stimulated by estrogen. New follicles develop, secreting estrogen more, causing mitosis and blood vessel growth (Day 5 = 0.5mm, Day 14 = 2-3mm thick). Estrogen stimulates endometrial cells to create progesterone receptors.
• Secretory phase: endometrium thickens due to progesterone secretion from the corpus luteum causing (Day 15 - 26) gland development and thickening due to glycogen secretion, rather than mitosis. Endometrium (5-6mm thick, soft, nutritious, etc.).
• Premenstrual phase: progesterone levels fall; corpus luteum atrophies; causes tissue necrosis, menstrual cramps, and mixes with blood and serous fluid to become menstrual fluid.
• The menstrual phase (menses) involves the discharge of menstrual fluids from the vagina. The first day of discharge marks the beginning of the next cycle. The average woman expels around 40mL of blood and 35mL of serous fluid over 5 days. It does not clot.
• Sexual response is divided into excitement, plateau, orgasm, and resolution phases.
• Excitement and plateau phases cause labia minora and majora engorgement and enlargement with fluid.
• The vagina constricts during orgasm (orgasmic platform), and pelvic thrusting occurs with pelvic throbbing and spreading sensation of warmth.
• Three to five strong pelvic platform contractions occur about 0.8 seconds apart.
• The cervix plunges spasmodically into the vagina, stimulating peristaltic uterine contractions, anal and urethral sphincter contraction, and possible paraurethral gland fluid release (similar to prostatic fluid in males). Women may experience reddish flush on lower abdomen, chest, neck, and face as well as tachycardia (rapid heart rate) and hyperventilation.
• Resolution phase involves uterus returning to its resting position; the orgasmic platform relaxes. Vagina returns to normal dimensions; flush disappears; areolae and nipples detumesce, and breasts take 5-10 minutes to return to normal size. Postorgasmic perspiration occurs; women do not have refractory periods.

Senescence of the Female Reproductive System

• Abrupt changes due to menopause occur when ovarian follicles are used up, gametogenesis ceases, and ovaries cease producing sex steroids; reduced libido, genital atrophy, elevated osteoporosis and atherosclerosis risks.

Climacteric and Menopause

• Climacteric is a midlife change in hormone secretion, with cessation of menstruation.
• Menopause is the cessation of menstrual cycles, occurring usually between ages 45 and 55, with ages increasing in the past century. Menopause is considered complete when there has been no menstruation for a period of time.

Fertility of Aging Females

• Peak fertility occurs in the early 20s.
• As females age, fertility dramatically declines by age 35.
• Birth defects increase dramatically after age 40.
• Xinju Tian, from China, age 65, gave birth during October 2019.
• Mangayamma Yaramati, from India, age 74, gave birth during September 2019. These are examples of the oldest recorded pregnancies.

Test your knowledge on menopause and the climacteric phase in females. This quiz covers various aspects including physiological changes, age factors, and symptoms associated with menopause. Gain a better understanding of this important stage in women's health.