Transcript 3. Female Reproductive System WEB

Reproductive System Cont.
Female Anatomy & Physiology
Chapter 28
FEMALE ANATOMY
• Ovaries = produce eggs
• Ovarian follicles = contain eggs in various stages of development
and the cells that surround them; surrounding cells nourish the
eggs & produce estrogen
• Corpus luteum = remnants of a mature follicle after ovulation
(after egg is released); produces estrogen, progesterone, and
relaxin
• Uterine tubes
(oviducts/fallopian tubes) =
transport eggs from the ovary to
the uterus; fertilization occurs in
the oviducts
• Uterus = organ in which the
fetus develops
• Endometrium = uterine lining
• Cervix = lower end of uterus
• Vagina = passageway between
the uterus and the outside
• Vulva = external genitals of the
female
Female
Reproductive
Cycles:
1. Ovarian Cycle
&
2. Menstrual
(Uterine) Cycle
Female Reproductive Cycles
Female reproductive cycles prepare the female body for
pregnancy
1. Ovarian cycle = cyclic events that occur in the ovaries
2. Menstrual (uterine) cycle = cyclic events that occur in the
uterus
• Last 28 days on average
• Influenced by
1. hormones secreted by pituitary gland: FSH and LH
2. hormones secreted by ovary: estrogen and progesterone
OVARIAN CYCLE
1. Follicular phase – prior to ovulation:
• One ovarian follicle becomes the dominant follicle and begins to
mature when the pituitary gland releases FSH
• Maturing follicle releases estrogen and causes the pituitary gland
to release LH (this is an example of positive feedback: an increase
in one hormone results in increase of another hormone)
2. Ovulation (day 14):
• levels of LH reach its peak and initiate ovulation
• Ovulation = egg is released from the dominant follicle
3. Luteal phase – after ovulation:
• Ruptured follicle becomes corpus luteum and secretes estrogen and
progesterone
• High levels of estrogen and progesterone inhibit FSH and LH (this
is an example of negative feedback: increase in one hormone
results in decrease of another hormone)
MENSTRUAL CYCLE
• If the egg does not become
fertilized, levels of estrogen
and progesterone fall and
cause endometrium to be
shed = menstrual flow or
menstruation (days 1-5)
• Starting with day 6,
increasing levels of
estrogen cause
endometrium to thicken and
prepare uterus for possible
implantation of fertilized
egg
FERTILIZATION
• Fertilization = union of
sperm and egg; the
resulting cell is called
zygote
• Takes place in the uterine
tube
IMPLENTATION
• Implentation
= the zygote
passes into
the uterus
where it
attaches into
the uterine
lining (by the
sixth day after
fertilization)