STRUCTURAL AND FUNCTIONAL ORGANIZATION OF THE FEMALE REPRODUCTIVE SYSTEM Flashcards
The organs of the female reproductive system
(1) Include the ovaries; the uterine (fallopian) tubes, (or oviducts); the uterus; the vagina; and external organs, which are collectively called the vulva, or pudendum.
(2) The mammary glands also are considered part of the female reproductive system
paired organs that produce secondary oocytes (cells that develop into mature ova, or eggs, following fertilization) and hormones, such as progesterone and estrogens (the female sex hormones), inhibin, and relaxin.
ovaries (egg receptacles)
a layer of simple epithelium (low cuboidal or squamous) that covers the surface of the ovary.
germinal epithelium
a region of dense connectivetissue that contains ovarian follicles.
Deep to the germinal epithelium
ovarian cortex
Each ovarian follicle (folliculus little bag) consists of
an oocyte and a variable number of surrounding cells that nourish the developing oocyte and begin to secrete estrogens as the follicle grows larger.
a large, fluid-filled follicle
that is preparing to rupture and expel a secondary oocyte.
mature (graafian) follicle
produces progesterone, estrogens, relaxin, and inhibin until it degenerates and turns into fibrous tissue called a corpus albicans (white body).
corpus luteum
consists of loose connective
tissue and contains blood vessels, lymphatic vessels, and nerves.
deep to the ovarian cortex
ovarian medulla
The open, funnel shaped end of each tube, lies close to the ovary, but is open to the pelvic cavity.
the infundibulum,
It ends in a fringe of fingerlike projections
fimbriae
How is the secondary oocyte directed to the uterine tube
After ovulation, local currents produced by movements of the fimbriae, which surround the surface of the mature follicle just before ovulation occurs, sweep the secondary
oocyte into the uterine tube
The oocyte is then moved along the tube by cilia in the tube’s mucous lining and ____ of its smooth muscle layer
peristaltic contractions
The usual site for fertilization of a secondary oocyte by a sperm cell is in the
uterine
tube
Fertilization may occur any time up to about ____ after ovulation
24 hours
The fertilized ovum (zygote) descends into the uterus how many days. Unfertilized
secondary oocytes disintegrate.
within seven days
Parts of the uterus
the dome shaped portion superior to the uterine tubes called the fundus, the tapering central portion called the body, and the narrow portion opening into the vagina called the cervix
interior of the body of the uterus
uterine cavity
The middle muscular layer of the uterus, consists of smooth muscleand forms the bulk of the uterine wall.
myometrium
innermost part of the uterine wall, is a mucous membrane. It nourishes a growing fetus or is shed each month during
menstruation if fertilization does not occur.
endometrium
What layer of the uterus contains many endometrial glands whose secretions nourish sperm and the zygote.
endometrium
A recess surrounds the cervix.
fornix
The mucosa of the vagina contains large stores of
glycogen
the decomposition of which
produces organic acids.
What about the vaginal environment retards microbial growth, but it also is harmful to sperm.
The resulting acidic environment from the decomposition of glycogen
the diamond-shaped area between the thighs and buttocks of both males
and females that contains the external genitals and anus
perineum
refers to the external genitals of the female
vulva, or pudendum,
The labia majora contain adipose tissue and what kind of glands
sebaceous (oil) and sudoriferous (sweat)
glands.
What kind of glands do the labia minora have
(a) The labia minora do not contain pubic hair or fat and have few sudoriferous (sweat) glands; they do contain numerous sebaceous (oil) glands.
The region between the labia minora
vestibule
Structures in the vestibule
the hymen vaginal orifice external urethral orifice on either side of the external urethral orifice, the openings of the ducts of the paraurethral glands.
These glands in the wall of the urethra secrete mucus.
Skene glands
On either side of the vaginal orifice itself are the greater vestibular glands, which produce a small quantity of mucus during sexual arousal and
intercourse that adds to cervical mucus and provides lubrication.
Bartholin
glands
What are modified sudoriferous (sweat) glands thatproduce milk.
mammary glands located in the breasts
The areola appears rough, why?
it contains modified sebaceous (oil) glands.
Internally, each mammary gland consists of ____lobes arranged radially and separated by adipose tissue and strands of connective tissue called suspensory ligaments of the breast
(Cooper’s ligaments), which support the breast.
15 to 20
During puberty, what hormones are responsible for the development of breasts
estrogens and progesterone
functions of the mammary glands
the synthesis, secretion, and ejection of milk;
these functions, called lactation, are associated with pregnancy and childbirth.
Milk production is stimulated largely by the hormone
prolactin from the anterior
pituitary, with contributions from progesterone and estrogens
The ejection of milk is stimulated by
oxytocin, which is released from the posterior pituitary in response to the sucking of an infant on the mother’s nipple.
During their reproductive years, non-pregnant females normally exhibit cyclical changes in
the ovaries and uterus.
Each cycle takes about a month and involves these two processes
oogenesis and preparation of the uterus to receive a fertilized ovum.
the formation and development of gametes in females.
Oogenesis
Hormones secreted which structures control the main
events of Oogenesis
the hypothalamus, anterior pituitary, and ovaries
what controls the uterine (menstrual) cycle? (a concurrent series of changes in the endometrium of the uterus to prepare it for the arrival of a fertilized ovum that will develop there until birth)
Steroid hormones released by the ovaries
What happens If fertilization does not occur
the levels of ovarian hormones decrease, which causes part of the endometrium to slough off
The general term female reproductive cycle encompasses
the ovarian and uterine cycles, the hormonal changes that regulate them, and the related cyclical changes in the breasts
and cervix
What hormone controls the ovarian and uterine cycles
Gonadotropin-releasing hormone (GnRH)
Order of hormone release, structure included
- GnRH (Hypothalamus) stimulates the release of FSH/LH (ant. pituitary)
- FSH initiates follicular growth and secretion of estrogen by the growing follicle
- LH stimulates the further development of ovarian follicles and their full secretion of estrogens.
- At mid-cycle, LH triggers ovulation and then promotes formation of the corpus luteum, the reason for the name luteinizing hormone
- Stimulated by LH, the corpus luteum produces and secretes estrogens, progesterone, relaxin, and inhibin
Estrogens secreted by ovarian follicles have several important functions throughout the
body
1) Estrogens promote the development and maintenance of female reproductive structures, feminine secondary sex characteristics, and the mammary glands.
a) The secondary sex characteristics include distribution of adipose tissue in the breasts, abdomen, mons pubis, and hips; a broad pelvis; and the pattern of hair growth on the head and body.
2) Estrogens stimulate protein synthesis, acting together with insulin-like growth factors, insulin, and thyroid hormones.
3) Estrogens lower blood cholesterol level, which is probably the reason that women under age 50 have a much lower risk of coronary artery disease than do men of comparable age
secreted mainly by cells of the corpus luteum
Progesterone
acts together with estrogens to prepare and then maintain the endometrium for implantation of a fertilized ovum and to prepare the mammary glands for milk secretion.
Progesterone
This hormone relaxes the uterus by inhibiting contractions of the myometrium.
A small quantity of relax.in, produced by the corpus luteum during each monthly cycle,
What does relaxin do?
inhibiting contractions of the myometrium
During pregnancy, the placenta produces much more relax.in, and it continues to
relax uterine smooth muscle
At the end of pregnancy, relax.in also increases the flexibility of the pubic
symphysis and helps dilate the uterine cervix, both of which ease delivery of the
baby.
What secretes inhibin
What is it inhibiting
growing follicles and by the corpus luteum after ovulation
secretion of FSH and, to a lesser extent, LH.
The duration of the female reproductive cycle varies from _____ days.
24 to 36
For discussion purposes, we assume a duration of 28 days and divide it into four phases:
the menstrual phase, the pre-ovulatory phase, ovulation, and the postovulatory phase
This phase lasts for roughly the first five days of the cycle.
Menstrual phase
(the first day of menstruation marks the first day of a
new cycle)
Menstrual phase
Events in the Ovaries
Events in the Uterus
(b) Events in the Ovaries
1) During the menstrual phase, several ovarian follicles grow and enlarge.
(c) Events in the Uterus
1) Menstrual flow from the uterus consists of 50 to 150 mL of blood and tissue cells
from the endometrium.
a) This discharge occurs because the declining level of ovarian hormones
(progesterone and estrogens) causes the uterine arteries to constrict.
b) As a result, the cells they supply become oxygen deprived and start to die.
Eventually, part of the endometrium sloughs off.
c) The menstrual flow passes from the uterine cavity to the cervix and through the
vagina to the exterior
The time between the end of menstruation and ovulation.
accounts for most of the variation in cycle length. In a 28-day cycle, it lasts from
days 6 to 13
Pre-ovulatory Phase
Pre-ovulatory Phase
Events in the Ovaries
Events in the Uterus
(b) Events in the Ovaries
1) Under the influence of FSH, several follicles continue to grow and begin to secrete estrogens and inhibin.
2) By about day 6, a single follicle in one of the two ovaries has outgrown all the others to become the dominant follicle.
3) Estrogens and inhibin secreted by the dominant follicle decrease the secretion of FSH, which causes other, less well developed follicles
to stop growing and die.
4) The one dominant follicle becomes the mature (graafian) follicle.
5) The mature follicle continues to enlarge until it is ready for ovulation, forming a blister like bulge on the surface of the ovary.
6) During maturation, the follicle continues to increase its production of estrogens
under the influence of an increasing level of LH.
7) With reference to the ovarian cycle, the menstrual phase and pre-ovulatory phase together are termed the follicular phase because ovarian follicles are growing and developing.
(c) Events in the Uterus
1) Estrogens liberated into the blood by growing ovarian follicles stimulate the repair of the endometrium.
2) As the endometrium thickens, the short, straight endometrial glands develop, and the arterioles coil and lengthen.
the rupture of the mature (graafian) follicle and the release of the secondary oocyte into the pelvic cavity, usually occurs on day 14 in a 28-day cycle
Ovulation
1) The high levels of estrogens during the last part of the pre-ovulatory phase exert a positive feedback effect on both LH and GnRH.
2) A high level of estrogens stimulates the hypothalamus to release more GnRH and the anterior pituitary to produce more LH.
3) GnRH then promotes the release of even more LH.
4) The resulting surge of LH brings about rupture of the mature (graafian) follicle and expulsion of a secondary oocyte.
5) An over-the-counter home test that detects the LH surge associated with
ovulation can be used to predict ovulation a day in advance.
Bullet points
the time between ovulation and onset of the next menstruation most constant in duration and lasts for 14 days, from days 15 to 28
in a 28-day cycle.
Postovulatory Phase
Postovulatory Phase
Events in the Ovaries
Events in the Uterus
(c) Events in One Ovary
1) After ovulation, the mature follicle collapses. Stimulated by LH, the
remaining follicular cells enlarge and form the corpus luteum, which secretes progesterone, estrogens, relaxin, and inhibin.
a) With reference to the ovarian cycle, this phase is also called the luteal phase.
2) Subsequent events depend on whether the oocyte is fertilized.
3) If the oocyte is not fertilized, the corpus luteum lasts for only two weeks, after which its secretory activity declines and it degenerates into a corpus albicans
4) As the levels of progesterone, estrogens, and inhibin decrease, release of GnRH, FSH, and LH rises due to loss of negative feedback suppression by the
ovarian hormones. Then, follicular growth resumes and a new ovarian cycle
begin.
5) If the secondary oocyte is fertilized and begins to divide, the corpus luteum
persists past its normal two week lifespan.
6) It is “rescued” from degeneration by human chorionic gonadotropin (hCG), a hormone produced by the embryo beginning about eight days after
fertilization.
7) Like LH, HCG stimulates the secretory activity of the corpus luteum. The
presence of HCG in maternal blood or urine is an indicator of pregnancy, and hCG is the hormone detected by home pregnancy tests.
(d) Events in the Uterus
1) Progesterone and estrogens produced by the corpus luteum promote growth of the endometrial glands, which begin to secrete glycogen, and vascularization and thickening of the endometrium.
2) These preparatory changes peak about one week after ovulation, at the time a fertilized ovum might arrive at the uterus.
