NUR 113Menstrual Cycle Study Guide1. Describe the role of the hypothalamus and its influence on the menstrual cycle.

The hypothalamus stimulates the release of LHRH (GnRH) and transmits to the anterior pituitary gland in response to signals received from the CNS. The pituitary gland then signals the release of the gonadotropic hormones FSH and LH. FSH is responsible for the maturation of the ovarian follicle. As the follicle matures, it secretes increasing amounts of estrogen, which enhances the development of the follicle. Final maturation of the follicle occurs with the aid of LH. LH stimulates the release of progesterone from the corpus luteum. Progesterone and estrogen increases as they prepare the endometrium for possible pregnancy. If fertilization does not occur, the rising level of progesterone inhibits the release of GnRH which inhibits further production of progesterone. As both levels drop, the corpus luteum degenerates, the endometrium breaks down as its cells die (apoptosis), uterine contractions occur, and the bleeding and cramps of menstruation begin. 2. What are the major functions of the follicle stimulating hormone in the process of ovulation? maturation of the ovarian follicle stimulates the release of estrogens enhances the development of the follicle oocyte growth within the follicle mature egg is released from the dominant follicle and the others disintegrate levels of estrogen signals the hypothalamus and pituitary gland of the mature egg3. Describe the uterine changes during the four phases of the menstrual cycle. MENSTRUAL = endometrial areas are shed, while others remain

some of the remaining tips of the endometrial glads regenerate

endometrium in resting state at 1-2 mm deep

estrogen levels are low

cervical mucosa is scanty, viscous, and opaque

PROLIFERATIVE = endometrial glands enlarge, becoming twisted and longer ( estrogen)

prominent blood vessels and become dilated

endometrium increases in thickness (reaches peak before ovulation)

cervical mucosa becomes thin, clear, watery, and more alkaline

makes mucosa more favorable to spermatozoa

near ovulation, the cervical mucosa increases elasticity (spinnbarkeit)

at ovulation the mucus stretches more than 5 cm

cervical mucosa pH increases from below 7.0 to 7.5 at ovulation (fern)

SECRETORY = the endometrium undergoes slight cellular growth

progesterone causes swelling and growth that causes epithelium to fold

tissue glycogen is increased

glandular epithelial cells begin to fill with cellular debris, twists, and dilates

glands secrete small amounts of endometrial fluid for fertilized ovum

uterine vascularity increases, providing a nourishing bed for implantation

if implantation occurs, the endometrium continues to develop and even

under the influence of progesterone ISCHEMIC = begins if fertilization does not occur

corpus luteum degenerates, estrogen and progesterone

areas of necrosis appear under the epithelial lining

extensive vascular changes occur

small blood vessels rupture

spiral arteries constrict and retract endometrial blood deficiency (pale)

blood escapes into the stromal cells of the uterus

menstrual flow begins thus restarting the menstrual cycle

afterwards, the basal layer remains so that the tips of the glands can

regenerate the new functional endometrial layer5. Ovulation usually occurs _____ days prior to menses.