Exam 5 Review:  Chapter 27 Female Reproductive Cycles

female reproductive cycle - The all-inclusive term for the many physiological and developmental changes which occur in the female throughout life, including (1) the life cycle of infertile childhood, puberty, fertile years of youth and adulthood, menopause, and finally infertile postmenopausal years; (2) the menstrual cycle which is a pair of series of ~monthly repetitive physiological and developmental changes (2a) in the ovaries, and (2b) in the uterus, as well as (2c) some minor changes in the breasts which accompany the menstrual cycle; and the possible transition from independent individual to mate, mother, and grandmother.  It's quite a story!

ovarian cycle - The series of ~monthly repetitive physiological and developmental changes in the ovaries, which prepare the ovaries for the ovulation of an egg = ovum and the subsequent development of a corpus luteum whose hormones will assist in regulating the uterine cycle and, if the implantation of a developing embryo occurs, assist in regulating the pregnancy; it is  regulated by FSH and LH from the anterior pituitary; it consists of four phases:  preovulatory, follicular, ovulatory, and luteal.  (See details below.)  [Note:  these phases run in parallel with the phases of the uterine cycle and together comprise the menstrual cycle.]

preovulatory phase - The first part of the ovarian cycle, ~days 1-5, during which the rising blood levels of FSH from the anterior pituitary stimulate some15-20 primordial follicles to develop further to form primary follicles, though by the end of the cycle all but ~one will be lost to atresia.

follicular phase - The second part of the ovarian cycle, days ~6-14, during which FSH and LH stimulate the growth of the set of primary follicles; the follicular = granulosa cells around the oocyte have grown, going from squamous to cuboidal; the oocyte has enlarged and the granulosa cells begin to divide around it to form a multicellular capsule known as the zona granulosa; the theca folliculi, a fibrous capsule made of connective tissue from the ovary forms around the primary follicle; the theca and granulosa cells start to produce estrogen; (LH causes the theca cells to produce androgens, which the granulosa cells change to estrogen under the influence of FSH); rising estrogen levels produce a negative feedback effect on the adenohypophysis and the hypothalamus which slows the release of FSH and LH; estrogen also intensifies the effect of FSH, causing the follicle to grow and also increasing the output of estrogen; an antrum, a fluid filled space, forms within the growing sphere of granulosum cells, defining the transition to secondary follicle; more developing follicles are lost to atresia; a zona pellucida forms around the oocyte; ~one secondary follicle matures into a vesicular = Graafian follicle; as estrogen continues to be secreted, its blood level reaches a critical point, causing a surge in LH and a smaller surge in FSH; this surge in LH causes the completion of meiosis I in the developing primary oocyte; this division yields two haploid cells: the first polar body and the secondary oocyte; the secondary oocyte receives almost all of the nutrient material found in the primary oocyte due to unequal cytoplasmic division.

ovulatory phase - The third part of the ovarian cycle, days ~13-15, during which the sudden surge in LH causes the smooth muscle surrounding the vesicular = Graafian follicle to contract causing the follicle to rupture and expel the secondary oocyte, which is arrested in metaphase II, along with its corona radiata capsule of follicular = granulosa cells through the germinal epithelium lining the ovary; it all goes well, the ovulated egg = ovum will be swept into the uterine tubes = oviducts.

luteal phase - The fourth and final part of the ovarian cycle, days ~15-28; the LH surge has one more function, to turn the follicular = granulosa cells left in the ruptured vesicular = Graafian follicle within the ovary into the corpus luteum; the corpus luteum secretes more progesterone and estrogen, which have a negative feedback effect on the release of LH and FSH from the anterior pituitary; this prevents the development of any new follicle;.as LH levels decline, the corpus luteum starts to degenerate, and the menstrual cycles can start again.  [Note:  If no pregnancy is established, then a decline of the corpus luteum, and a restart of the cycle; if pregnancy is established, then a corpus luteum is maintained and continues to secrete estrogens and progesterone to complement the added placental secretion; from the ovary, the secondary oocyte travels to the uterine tube = oviduct where a combination of smooth muscle peristalsis and the ciliated cells' current flow help to move the oocyte to the uterus; ideally, fertilization should takes place within the uterine tube = oviduct.

uterine cycle - The series of ~monthly repetitive physiological changes in the lining of the uterus, the stratum functionalis of the endometrium, which prepare the uterine lining for the possible implantation of a developing embryo; it is  regulated by FSH and LH from the anterior pituitary; it consists of three phases:  menstrual, proliferative, and secretory.  (See details below.)  [Note:  these phases run in parallel with the phases of the ovarian cycle and together comprise the menstrual cycle.]

menstrual phase - The first part of the uterine cycle, ~days 1-5, during which the stratum functionalis degenerates and breaks away from the uterine wall and passes through the vagina as the menstrual flow = menses.

proliferative phase - The second part of the uterine cycle, days ~6-14, during which the stratum functionalis layer of the endometrium is being rebuilt under the influence of increased estrogen; the spiral arteries are proliferating and progesterone receptors are being created in the endometrium; at this time estrogen will also cause the cervical mucus to become thin and fluid to facilitate entry of sperm into the female reproductive system.

secretory phase - The third and final part of the uterine cycle, ~days 15-28, during which progesterone causes the spiral arteries to elaborate and coil; the stratum functionalis starts to secrete glycogen, which will help to nourish any developing embryo; the cervical mucus will thicken to form the cervical plug, which will block entry of any sperm cells and protect the embryo, if present, from microbes; if no fertilization occurs, the corpus luteum of the ovary will degenerate and progesterone levels will drop off, this causes the spiral arteries to kink, depriving the endometrium of oxygen and nutrients; the stratum functionalis starts to degenerate, being partially digested by lysosomes, and will be sloughed.

menstrual cycle - The series of ~monthly repetitive physiological changes in the ovaries and in the lining of the uterus, the stratum functionalis of the endometrium, which prepare an ovarian follicle for ovulating and prepare the uterine lining for the possible implantation of a developing embryo, should fertilization of the egg = ovum occur; it is regulated by FSH and LH from the anterior pituitary; it consists of two parallel cycles, the ovarian cycle and the uterine cycle.  See the details of the two parallel cycles above.

menstruation - The cyclic, ~ monthly, process or an instance of discharging the menses (blood tinged sloughed off endometrial tissue) from the uterus of nonpregnant women through the vagina from puberty to menopause; it is  regulated by FSH and LH from the anterior pituitary; this process marks the end of one mentrual cycle and the beginning of the next one.

menses - The discharged material or flow of blood tinged sloughed off endometrial tissue from the uterus of nonpregnant women through the vagina; cyclic, ~ monthly, process occurring from puberty to menopause under the regulation of FSH and LH from the anterior pituitary.
 

Sketch and label:

15.  a diagram or chart illustrating the histological changes and naming the phases in the female uterine cycle.