Female reproductive system Flashcards
components of vulva
mons pubis - fat layer in front of pubic symphysis
labia majora - larger, more lateral
labia minora - smaller and more medial
vestibule = between labia
clitoris
structure of clitoris
complex erectile organ
Glans, body, crura (x2), bulbs (x2)
Bulbs of vestibule are part of erectile tissue in clitoris of females
Developmentally homologous to the penis
Urethra does not pass through the clitoris, has separate opening
functions of female reproductive tract
Allows transport of sperm and ova to the site of fertilization
Provides a site for the developing embryo and fetus to grow – protection, nourishment
Delivery of fetus
structures in female reproductive tract
Ovary
Uterine tubes
Uterus (top end = fundus, rest = body)
Cervix
Vagina
structure of uterus
Anteverted - leans forward over urinary bladder
3 major components: fundus, body and cervix
Uterine wall has 3 layers: perimetrium, myometrium and endometrium
function of uterus
Movement of sperm, implantation of blastocyte
Retain and nourish embryo and fetus through pregnancy
Allow parturition (childbirth)
structure of uterine wall
Perimetrium - outer layer (connective tissue)
Myometrium - middle layer (smooth muscle)
Endometrium - inner layer (columnar epithelium, uterine glands and arteries). Layer that grows and sheds during menstrual cycle
3 parts of uterine tube
- infundibulum - most lateral, has fimbriae (fingerlike projections)
- ampulla - midportion, where fertilisation occurs
- isthmus - most medial
3 parts of cervix
external os
cervical canal
internal os
structure of vagina
Lies between the urinary bladder & rectum
Extends from the perineum to the cervix
fibromuscular, distensible female copulatory organ
blood supply to uterus
abdominal aorta –> common iliac –> uterine artery
blood supply to vagina
abdominal aorta –> vaginal artery
blood supply to ovaries
abdominal aorta –> ovarian arteries
types of arteries in uterus
Spiral arteries are coiled, for deep blood supply
Straight arteries don’t go as deep
Arcuate artery goes around uterus
structure of ovaries
Lateral and posterior side of the uterus in the lateral portion of the true pelvic cavity.
Outer cortex (follicles) and inner medulla (connective tissue, blood vessels, nerves and lymphatics)
function of ovaries
Site of oogenesis
Hormone production
4 ligaments
- broad ligament
- ovarian ligament - between uterus and ovaries
- suspensory ligament
- round ligament - laterally from uterine tubes
subdivisions of broad ligament
Mesometrium = over uterus
Mesosalpinx = over tube
Mesovarium = over ovary
vesicouterine pouch
Continuous fold of broad ligament (visceral peritoneum) over anteriorly located bladder
rectouterine pouch
Continuous fold of broad ligament (visceral peritoneum) over posteriorly located rectum
what is oogenesis
formation and development of oocyte from oogonia
oogenesis before birth
- oogonium (diploid 2n=46) migrate to developing gonad
- population of oogonia increase by mitosis
- oogonia differentiate to form primary oocytes (diploid 2n=46)
- primary oocytes start meiosis
- meiosis halts at prophase 1 until puberty
oogenesis at puberty
- primary oocyte completes meiosis 1, forms secondary oocyte and first polar body (both n=23)
- secondary oocyte starts meiosis 2
- meiosis 2 halts at metaphase 2 until fertilisation
end product of one primary oocyte
one ovum and 3 polar bodies which undergo atresia (cell death)
structure of oocyte within follicle
oocyte surrounded by cells called corona radiata
follicle is multilayered, made of granulosa cells (produce estradiol) and theca cells
where is GnRH made and what does it do
made is hypothalamus, stimulates release of FSH and LH
where is FSH released and what does it do
released in ant. pit
stimulates growth of ovarian follicles
where is LH released and what does it do
released from ant pit
surge in LH involved in ovulation, formation of corpus luteum
where is estradiol made and what does it do
made in developing follicles
Assists follicle growth (w/ FSH); bone and muscle growth; endometrial growth; secondary sex characteristics; feedback to anterior pituitary
where is inhibin made and what does it do
made in granulosa cells
negatively feed back to ant pit to suppress FSH
where is progesterone made and what does it do
made in corpus luteum
Negatively feeds back to suppress GnRH (therefore LH and FSH); endometrial maturation; maintains pregnant state
2 phases of ovarian cycle
- follicular phase (day 1-14)
- luteal phase (day 15-28)
hormonal changes in follicular phase
- Increased FSH from the anterior pituitary
- Stimulates follicular growth
- Growing follicles secrete estradiol and inhibin
- Reduces FSH from anterior pituitary (negative feedback)
- Growing follicles undergo atresia, except dominant follicle.
- Dominant follicle secretes large amounts of estradiol
- High estradiol stimulates surge of LH (positive feedback)
- Follicle ruptures and ovulation occurs
- Oocyte enters peritoneal space/collected into uterine tube
process of luteal phase
- Ovulated follicle collapses & forms corpus luteum
- Secretes progesterone, estradiol & inhibin.
- These decrease FSH & LH secretion
- Negative feedback on hypothalamus.
- Progesterone stimulates maturation of the endometrium
- Glands become secretory
- If pregnancy does not occur, the corpus luteum involutes (luteolysis).
- Fall in progesterone & estradiol.
- Endometrium breaks down and bleeds (menstruation)
- Removes negative feedback on FSH and LH
menarche: what, when, why
first menstrual period
Occurs at age 12-13 y on average
Part of puberty – orchestrated by increase in sex steroid production (estrogens) by the gonads
menopause: what, when, why
cessation of menstruation
Typically occurs in early 50s.
Reduction of estradiol and progesterone.
Due to absence of or non responsiveness of follicles.
Anterior pituitary feedback no longer active, therefore FSH/LH high
phases in menstrual cycle
- menstrual phase (day 1-6)
- proliferative phase (day 1-15)
- secretory phase (day 15-28)
process of proliferative phase
- Estradiol stimulates endometrial growth from approx days 6-14
- Rapid tissue growth, including growth of glands and vasculature
process of secretory phase
- After ovulation (day 14) - corpus luteum secrets progesterone.
- Progesterone promotes endometrial maturation
- Glands become secretory
- Spiral arterioles grow and coil
- If pregnancy does not occur:
- Corpus luteum atrophies
- Progesterone levels fall
- Spiral arteries contract
- Endometrial tissue breaks down and bleeding occurs
- Shed tissue and blood removed via cervix and vagina (menstruation / menses)
function of ovarian cycle
To produce ovum each month to regulate the menstrual cycle
function of menstrual cycle
To ensure lining of uterus suitable for implantation
function of breasts
milk to nourish infants
structure of breasts
Lie on pectoralis major muscles.
Lobes ⇒ lobules ⇒ alveoli ⇒ lactiferous ducts ⇒ lactiferous sinuses that open at nipple pores.
Suspensory ligaments support the glands
what stimulates development of breast tissue
estradiol and progesterone
what stimulates lactation (milk production)
- Rapid reduction in circulating estradiol and progesterone after birth allows breasts to respond to prolactin (anterior pituitary).
- Prolactin stimulates milk production/ secretion/synthesis.
- Suckling stimulates continued production of prolactin (anterior pituitary).
- Amount of prolactin determined by strength/duration of nipple stimulation during suckling
what stimulates milk ejection
- Suckling also stimulates oxytocin secretion (posterior pituitary).
- Oxytocin stimulates contraction of smooth muscle around alveoli.
- Milk goes into lactiferous ducts allowing infant to feed.
