Dec 26, 2015
External Genitalia (Vulva)
• Labia – skin folds– Labia majora– Labia minora
• Urethra- urination• Clitoris
– Contains erectile tissue– Corresponds to the male penis
Vagina
• Extends from cervix to exterior of body• Behind bladder and in front of rectum• Serves as the birth canal• Receives the penis during sexual
intercourse
Uterus• Located between the urinary bladder and
rectum• Hollow organ• Functions of the uterus– Receives a fertilized egg– Retains the fertilized egg– Nourishes the fertilized egg
• Fundus – area where uterine tube enters• Cervix – narrow outlet that protrudes into the
vagina
Uterine (Fallopian) Tubes• Receive egg as it is released from the follicle• Does not physically attach to the ovary
• Fimbriae – finger-like projections at the distal
end that receive the egg
• Cilia inside the fallopian tube slowly move the
egg towards the uterus (takes 3–4 days)
• Fertilization occurs inside the fallopian tube
Ovaries
• Composed of ovarian follicles
• Structure of an ovarian follicle– Oocyte (future egg)– Follicular cells
• Ovarian Follicle Stages:– Primary follicle –
contains an immature oocyte– Graafian follicle – growing follicle with a maturing
oocyte– Ovulation – when the egg is mature the follicle ruptures
• Occurs about every 28 days– The ruptured follicle is transformed into a corpus
luteum (secretes hormones)
Sexual Maturation & Reproduction
• In females, the total supply of eggs are present at birth, but the ability to release eggs only begins at puberty.
• During fetal development the ovaries contain several million immature oocytes
• A birth, no new ones are formed, many degenerate and only approximately one million remain
• By puberty, only approximately 400,000 are left• Fewer than 400-500 are released throughout the
female reproductive life (on average one per month)• Female reproductive ability ends with menopause
Menstrual (Uterine) Cycle• Cyclic changes of the endometrium (uterine lining)– Averages 28 days
• Regulated by cyclic production of estrogens and progesterone
• Stages of the menstrual cycle– Proliferative stage – regeneration of functional
layer– Ovulation- the follicle is stimulated to release the
egg– Secretory stage – endometrium increases in size
and readies for implantation– Menses – functional layer of the endometrium is
sloughed
Hormone Production by the Ovaries• Estrogens– Produced by follicle cells– Cause secondary sex characteristics• Enlargement of accessory organs• Development of breasts• Appearance of pubic hair• Increase in fat beneath the skin• Widening and lightening of the pelvis• Onset of menses
• Progesterone– Produced by the corpus luteum– Production continues until LH diminishes in the
blood– Helps maintain pregnancy
• Work together to develop uterine lining
Hormone Production by the Ovaries
• Follicle Stimulating Hormone (FSH)– Stimulates the development of the follicle– Initiates the release of the egg from the follicle
• Luteinizing Hormone– Helps to stimulate egg production and release– Involved with the development of the
Endometrium
Walls of the Uterus• Endometrium– Inner layer (uterine lining)– Allows for implantation of a
fertilized egg– Sloughs off if no pregnancy occurs
(menstruation)• Myometrium – middle layer of smooth
muscle
Sexual Maturation & Reproduction
• Ovulation occurs about 14 days before the end of the cycle
• If no sperm is present in the fallopian tubes shortly after ovulation, there is no fertilization– ovaries stop releasing estrogen & progesterone • the endometrium breaks down & is shed as menses• causes irritability, depression, breast tenderness =
PMS
Sexual Maturation & Reproduction• If sperm is present in the fallopian tubes it joins
with the egg for fertilization– Fertilized egg travels down the fallopian tube– zygote implants in endometrium– corpus luteum continues to release progesterone &
estrogen• Supports the vascular & muscular development of uterus
– uterine wall develops placenta• Important for gas exchange b/t mom & baby• Produces hormone (HCG) Human Chorionic Gonadotropin
which stimulates the corpus luteum to continue releasing hormones
• Is the “afterbirth” after delivery