Female Reproductive Anatomy
• The uterus is a pear shaped organ situated
between the urinary bladder and the rectum
– It serves as part of the pathway for sperm deposited
in the vagina to reach the uterine tubes
– It is also the site of implantation of a fertilized ovum,
development of the fetus during pregnancy, and
labor
– During reproductive cycles when implantation does not
occur, the uterus is the source of menstrual flow
Female Reproductive Anatomy
• Anatomical subdivisions of the uterus include:
– A dome-shaped superior portion called the fundus
– A central portion called the body, that tapers to a
narrow isthmus
– the inferior-most
cervix opens into
the vagina through
the cervical
canal
Female Reproductive Anatomy
• The interior of the body of the uterus is called
the uterine cavity
• The cervical canal
has an internal os
and an external os
that opens into
the uterine
cavity and the
vagina, respectively
Female Reproductive Anatomy
• The vagina is a fibromuscular canal lined with
mucous membrane that extends from the
exterior of the body to the uterine cervix. It is
composed of both longitudinal and circular
muscle, and has 3 basic functions:
– Serve as a passageway
for menstrual flow
– Receive sperm
– Form the lower
birth canal
Female Reproductive Anatomy
• The vulva (female external genitalia) refers to
the:
– Mons pubis (created by adipose tissue)
– Erectile tissue of the clitoris
– Labia majora (outer limits of
vulva) and labia minora
(covers the vestibule)
– Vestibule, the
area between the
labia minora
– Vaginal orifice
(opening)
Female Reproductive Anatomy
• Anterior to the vaginal orifice and posterior to
the clitoris is the opening of the external
urethral orifice
– Mucus-secreting paraurethral glands flank the
orifice (homologous to the prostate gland in males)
• On either side of the vaginal orifice itself are
the greater vestibular (Bartholin’s) glands
which open by ducts into a groove between the
hymen and labia minora. They produce a small
quantity of lubricating mucous during sexual
arousal
Female Reproductive Anatomy
• The perineum denotes the diamond-shaped
area medial to the thighs and buttocks of
females (and males) – the entire undersurface
of the pelvis
– It contains the external
genitalia and
anus
Female Reproductive Anatomy
Female Reproductive Anatomy
• The breasts (mammary glands) are modified
sudoriferous glands that produce milk: Each
contains 15–20 lobes divided into lobules
– Each lobule is
composed of milksecreting glands called
alveoli. The nipple has a
pigmented area (areola)
and openings for the
lactiferous ducts
Female Reproductive Anatomy
Female Reproductive Physiology
• During reproductive years, nonpregnant females
normally exhibit cyclical changes in the ovaries
and uterus
– Each cycle takes about a month and involves both
oogenesis (ovarian cycle) and preparation of the
uterus to receive a fertilized ovum with hormones
secreted by the hypothalamus, anterior pituitary,
and ovaries controling the main events
The Female Reproductive Cycle
• The hormones secreted in the brain constitute the
part
of the cycle called the hypothalamic/pituitary cycle.
Those hormones are GnRH, FSH, and LH
–The reproductive organs in the female pelvis respond to
the brain hormones by cycling at two “lower” levels
• the ovarian cycle occurs in the ovaries where 1o , 2o and 3o
follicles are formed
• the uterine cycle refers to the monthly cycling of
the endometrium when a woman is not pregnant
The Ovarian Cycle
• The formation of gametes in the ovaries is
termed oogenesis. In contrast to
spermatogenesis, which begins in males at
puberty, oogenesis is more complex and begins
in females before they are even born
– During early fetal development, primordial germ
cells migrate from the yolk sac to the ovaries where
they differentiate into oogonia
• Oogonia are diploid (2n) stem cells that divide mitotically
to produce millions of germ cells
The Ovarian Cycle
• Even before birth, most oogonia degenerate,
though a few develop into larger cells called 1o
oocytes that enter prophase of meiosis I
(during fetal development) but do not complete
it until a fortunate few are called upon to do so
during the reproductive years
– During the interim (an arrested
stage of development), each 1o
oocyte is surrounded by follicular
cells in a primordial follicle
The Ovarian Cycle
• At puberty, under the influence of LH and FSH (the
brain gonadotropins), several primordial follicles will
be stimulated each month, although only one will
typically reach the maturity needed for ovulation
– Maturing oocytes within maturing follicles undergo a
series of developmental stages which ultimately brings
one 2o oocyte within a 3o follicle to the point of
ovulation
• the ovulated 2o oocyte will have completed meiosis I, and so
have the haploid number of chromosomes (1n)