A&P ch 46

Rectouterine pouch

Also called posterior cul-de-sac (of Douglas) a deep pouch between the uterus and the anus; formed by the posterior ligament.

Be able to identify the following in a diagram

Diagram 46-1 Uterine tube (Fallopian tube) Fundus of uterus Cervix Fornix of vagina Urinary bladder Urethra Vagina Clitoris Labium minus Labium majus Anus

Be able to identify the following in a diagram (cont..)

Diagram 46-3 Ovary Fimbriae Infundibulum of uterine tube Ampulla of uterine tube Isthmus of uterine tube Fundus of uterus Myometrium Endometrium Internal os of cervix Cervical canal External os of cervix Fornix of vagina

Spinnbarkeit

characteristic of fluids that allow them to be stretched into a fiber; fibrosity; observed cervical mucus around the time of ovulation.

Broad ligament

double fold of parietal peritoneum that forms a partition across the pelvic cavity.

Menarche

first menses occurring at the onset of puberty

Uterosacral ligament

foldlike extension of the peritoneum from the posterior surface of the uterus to the sacrum

Labia majora

large lateral folds of the vulva

Menstruation

menses; regular event of the female reproductive cycle that allows the endometrium to renew itself.

Colostrum

thin, yellowish secretion (early milk).

Explain the structure and function of the endometrium

-Composed of three layers of tissues: • Compact layer—a compact surface layer of partially ciliated, simple columnar epithelium • Spongy layer—a spongy middle, or intermediate, layer of loose fibrous connective tissue; also called functional layer • Basal layer—a dense inner layer that attaches the endometrium to the underlying myometrium. Varies in thickness from 0.5 mm just after the menstrual flow to about 5 mm near the end of the endometrial cycle. Rich supply of capillaries and numerous exocrine uterine glands (secrete mucus and other substances onto the endometrial surface. -The mucous glands in the lining of the cervix produce mucus that changes in consistency during the female reproductive cycle. Most of the time, cervical mucus acts as a barrier to sperm. -Around the time of ovulation, however, cervical mucus becomes more slippery and actually facilitates the movement of sperm through the cervix and into the body of the uterus.

Explain the structure and function of the perimetrium

-External layer of serous membrane that forms part of the visceral peritoneum. This serous covering of the uterus is incomplete because it covers none of the cervix and only part of the body (all except the lower one fourth of its anterior surface). -The fact that the entire uterus is not covered with peritoneum has clinical significance because it makes it possible to perform operations on this organ without the same risk of infection that occurs in procedures that cut through the peritoneum.

State where and how milk is produced in the mammary glands, including the hormones regulating lactation

-Mammary glands in the breasts. -Mechanism controlling lactation: a. Ovarian hormones make the breasts structurally ready to produce milk b. Shedding of the placenta results in a decrease of estrogens and thus stimulates prolactin c. Prolactin stimulates lactation d. Additional hormones (e.g., oxytocin) also support lactation

Explain the structure and function of the myometrium

-thick, middle layer of the uterine wall. It consists of three layers of smooth muscle fibers that extend in all directions, longitudinally, transversely, and obliquely, and give the uterus great strength. The bundles of smooth muscle fibers interlace with elastic and connective tissue components and generally blend into the endometrial lining with no sharp line of demarcation between the two layers. -The myometrium is thickest in the fundus and thinnest in the cervix—a good example of the principle of structure fits function. To expel a fetus—that is, move it down and out of the uterus—the fundus must contract more forcibly than the lower part of the uterine wall, and the cervix must be stretched or dilated.

Explain the sequence of events during the female ovarian cycle

1. Ovaries at time of birth contain oocytes in primary follicles in which the meiotic process has been suspended 2. After puberty, about 20 or so of the oocytes resume meiosis each day; most of these will undergo atresia (degeneration) and disappear 3. Meiosis will stop again just before an ovum (usually just one) is released during ovulation. 4. Just before ovulation, the meiosis within the oocyte of the mature follicle halts again. It is this cell, which has not quite completed meiosis, that is expelled from the ruptured wall of the mature follicle during ovulation. Meiosis is completed only when, and if, the head of a sperm cell is later drawn into the ovum during the process of fertilization.

List the stages of ovarian follicle development

1. The primary follicle is surrounded by a single layer of granulosa cells. As maturation proceeds, the number of granulosa cell layers increases and the cells begin secreting increasing amounts of an estrogen-rich fluid that pools around the oocyte in a space called an antrum. 2. The outer layer of granulosa cells in a developing follicle condenses into a layer of theca cells. 3. The theca cell layer soon separates into an outer layer, or theca externa, which transforms into a fibrous capsule surrounding the follicle, and a theca interna layer of cells, which secrete a precursor androgen hormone that granulosa cells ultimately convert into additional estrogen. 4. As the primary follicle matures into a secondary, then eventually into a mature vesicular ovarian follicle or graafian follicle, a clump of granulosa cells called cumulus cells attaches the oocyte to the follicle wall, where it is surrounded by fluid in the antrum. 5. This mass of cells continues to cover the mature ovum, as it is called, after its release from the follicle. Cumulus cells secrete progesterone, which helps attract sperm cells toward the ovum and promotes sperm motility. The developing oocyte also secretes the zona pellucida (ZP). 6. The release of an ovum at the end of oogenesis is an event called ovulation. When ovulation occurs, blood hemorrhages from the highly vascular theca interna cell layer and fills the antrum. A small quantity of blood may also enter the peritoneal cavity and irritate its pain-sensitive surface, causing the transient lower abdominal pain many women experience at the time of ovulation (Mittelschmerz aka "middle pain"). 7. The blood clot filling the antrum, sometimes called the corpus hemorrhagicum, is soon replaced by proliferating granulosa and theca interna cells to form a yellow body called the corpus luteum. 8. The corpus luteum secretes the hormones progesterone, inhibin, relaxin, and limited amounts of estrogen. Progesterone and inhibin, suppress follicle-stimulating hormone (FSH) secretion and prevent the continued development of new follicles during the functional life of the corpus luteum. 9. The small amounts of relaxin secreted by the corpus luteum each month help "quiet" or "calm" uterine contractions, thus improving the chances for successful implantation if fertilization should occur. If pregnancy does occur, larger amounts of these hormones continue to be produced by the placenta.

Graafian follicle

A secondary follicle; consists of a mature ovum surrounded by granulosa cells at boundary of fluid-filled antrum.

Describe the structure and function of the uterine tubes (Fallopian tubes)

Also called oviducts. Structure: 1. Uterine tubes consist of mucous membrane, smooth muscle, and serous lining. 2. Mucosal lining is directly continuous with the peritoneum lining the pelvic cavity (Tubal mucosa is continuous with that of the vagina and uterus, which means it may become infected with organisms introduced into the vagina and thereby cause salpingitis or peritonitis. Inflammation of uterine tubes may lead to scarring and partial or complete closure of the lumen). 3. Each uterine tube has three divisions: isthmus, ampulla, and infundibulum Function—serve as transport channels for ova and as the site of fertilization.

hormonal changes during the cycle

Control of female reproductive cycles: 1. Hormones control cyclical changes 2. Cyclical changes in the ovaries result from changes in the gonadotropins secreted by the pituitary gland. 3. Cyclical changes in the uterus are caused by changes in estrogens and progesterone. 4. Low levels of FSH and LH cause regression of the corpus luteum if pregnancy does not occur; this causes a decrease in estrogen and progesterone, which triggers endometrial sloughing of the menstrual phase 5. Control of cyclical changes in gonadotropin secretion is caused by positive and negative feedback mechanisms and involves estrogens, progesterone, and secretion of releasing hormones by the hypothalamus

Identify the essential and accessory organs of reproduction in the female

Essential: Ovaries (gonads) & the ova (gametes) the ovaries produce. Accessory: Uterine tubes, uterus, vagina, vulva, mammary glands.

Hymen

Greek for "membrane"; mucous membrane that may partially or entirely occlude the vaginal outlet

Ovulation

Release of an ovum from the ovary at the end of oogenesis.

Corpus luteum

a hormone-secreting glandular structure formed after ovulation at the site of the ruptured follicle; it secretes chiefly progesterone with some estrogen.

Greater vestibular glands (Bartholin glands)

either of the glands on each side of the vaginal orifice that secrete a lubricating fluid.

Round ligament

fibromuscular cord that extends from the upper, outer angles of the uterus through the inguinal canals and terminating in the labia majora.

Perineal body

node formed by fibers from several muscles that form the pelvic floor.

Oogonia

primitive cell from which oocytes derive meiosis

Mons pubis

skin-covered pad of fat over the pubic symphysis in the female

Labia minora

small medial folds of the vulva.

Menopause

termination of menstrual cycles; also called climacteric

Lesser vestibular glands (Skene glands)

tiny mucous gland located near the female's urinary meatus by way of two small ducts.

Explain the sequence of events during the female endometrial (menstrual) cycles

Menstrual cycle (endometrial cycle) bits of the compact and spongy layers of the endometrium slough off, leaving denuded bleeding areas. After menstruation, the cells of these layers proliferate, causing the endometrium to reach a thickness of 2 or 3 mm by the time of ovulation. During this period, endometrial glands and arterioles grow longer and more coiled—two factors that also contribute to the thickening of the endometrium. After ovulation, the endometrium grows still thicker, reaching a maximum of about 4 to 6 mm. Then, the day before menstruation starts again, a drop in progesterone causes muscle in the walls of the tightly coiled arterioles to constrict, producing endometrial ischemia. This leads to death of the tissue, sloughing, and once again, menstrual bleeding. -Divided into four phases: Menses: or menstrual period, occurs on days 1 to 5 of a new cycle. There is some individual variation, however. Postmenstrual phase: Occurs between the end of the menses and ovulation making it the preovulatory phase as well as the postmenstrual phase. In a 28-day cycle, it usually includes cycle days 6 to 13 or 14. However, the length of this phase varies more than the others. It lasts longer in long cycles and ends sooner in short cycles. is also called the estrogenic phase, or follicular phase, because of the high blood estrogen level resulting from secretion by the developing follicle. Increases in estrogen levels cause predictable changes in the appearance, amount, and consistency of cervical mucus. Collectively, these changes can be used as a fertility sign to predict ovulation. Increasing estrogen levels cause cervical mucus to become elastic. The clear, watery cervical mucus found at the time of ovulation will stretch 8 cm or more before the resulting thread will break. This stretchiness is called spinnbarkeit. If left to dry on a clean glass slide, cervical mucus produced at or near the time of ovulation will dry in a characteristic featherlike or "fern" pattern. Ovulation: rupture of the mature follicle with expulsion of its ovum into the pelvic cavity. —occurs most often on cycle day 14 in a 28-day cycle. because the majority of women show some month-to-month variation in the length of their cycles, the day of ovulation in a current or future cycle cannot be predicted with accuracy based on the length of previous cycles. there is a decrease in basal body temperature just before ovulation and a rise in temperature at the time of ovulation. This constitutes yet another "fertility sign". Premenstrual phase: or postovulatory phase, occurs between ovulation and the onset of the menses. This phase is also called the luteal phase, or more simply the secretory phase, because the corpus luteum secretes only during this time. It is also called the progesterone phase because the corpus luteum secretes mainly this hormone. The length of the premenstrual phase is fairly constant, lasting usually 14 days—or cycle days 15 to 28 in a 28-day cycle. Differences in length of the total menstrual cycle therefore exist mainly because of differences in duration of the postmenstrual rather than of the premenstrual phase.

Describe the normal positioning of the uterus in the pelvic cavity

Normally said to be anteflexed, or "bent forward"-between the body and cervix, Body lies flexed over the bladder, pointing forwards and slightly upward. Cervix points downward and backward, joining the vagina at approximately a right angle.

Mesovarium

Structure which contains blood vessels and nerves. Portion of the broad ligament of the uterus that reflects onto and suspends the ovary.

Describe the structure and function of the vagina

Structure: 1. A collapsible tube capable of distention, composed of smooth muscle, and lined with mucous membrane arranged in rugae 2. Anterior wall shorter than the posterior wall because the cervix protrudes into its uppermost portion 3. Hymen—a mucous membrane that typically forms a border around the vagina in young premenstrual girls Functions: 1. Lining of the vagina lubricates and stimulates the penis during sexual intercourse and acts as a receptacle for semen 2. Vagina is the lower portion of the birth canal 3. Vagina transports tissue and blood shed during menstruation to the exterior.