Unit Four

“Female Reproductive System”

Female Reproductive System

• Primary Sex Organs – Paired Ovaries

• Secondary Sex/Accessory Organs – include the Uterus, Fallopian Tubes, Vagina, Cervix, and the Endometrium

Female Reproductive System

• Primary Sex Organs– The Paired Ovaries are oval shaped

structures that contain the eggs used in reproduction

– They also produce the female sex hormones, Estrogen and Progesterone, which are needed for the successful release of the eggs

Female Reproductive System

– Each Ovary is located within the abdominal cavity just above either pelvic bone

– Several ligaments hold the ovaries in place by attaching to the Uterine Tubes, Uterus, and the Pelvic Wall

– The interior of Ovary is composed of two sections:

• Outer Cortex – contains many follicles at various stages of maturation

• Inner Medulla – area where blood vessels and nerves enter the ovary

Female Reproductive System

• Immature eggs, called Oocytes, are contained within larger structures called Follicles

• A female is born with as many as 2 million follicles but of that large number, only approximately 400 will mature

• As stated previously, females are born containing all the follicles they will every possess. Therefore, the older the woman is when she conceives, the higher the likelihood for genetic abnormalities in the baby. The eggs have been in storage for an extended period of time.

Oogenesis

• Oogenesis is the process by which mature eggs are produced via meiosis

• As with Spermatogenesis, Oogenesis begins with a Primary Oocyte that proceeds through Meiosis I

• Once the Primary Oocyte has successfully completed Meiosis I, it is now a Secondary Oocyte that will then become the mature egg

Oogenesis

• 1. Recall the Follicle contains the developing egg

• 2. As the Follicle matures, Primary Oocyte divides, producing two cells

• 3. Of the two cells, one is the Secondary Oocyte, and the other is a Polar Body

• 4. During Ovulation, the Follicle bursts, releasing the Secondary Oocyte

• 5. The Secondary Oocyte enters the Fallopian Tube where it may successfully unite with a Sperm

Oogenesis

• The Ovaries alternate monthly in producing a mature Follicle that will burst releasing a Secondary Oocyte

• The number of Secondary Oocytes produced by a female in her lifetime is tiny compared to the number of Sperm a male produces during his lifetime

Female Reproductive System

Female Internal Accessory Organs

• Fallopian/Uterine Tubes – long tubular structures; allows for passage of the

fertilized secondary oocyte (blastomere) from the ovaries to the uterus via the back and forth action of cilia (microscopic hairs)

• It takes several days for the blastomere, now becoming the Blastocyst to enter the Uterus, and then become embedded in the Uterine lining

• Ectopic Pregnancy – a Blastocyst that becomes embedded in the wall of the Fallopian Tubes; does not result in a viable fetus

Female Internal Accessory Organs

• Uterus – It is found adjacent to the Urinary Bladder,

and is centrally located in the lower abdominal cavity of a female

– It is a thick walled muscle that has the shape of an inverted pear

Female Internal Accessory Organs

• Uterus continued– Three layers of the Uterus: Outer, Middle, and

Inner Layers• Outer – part of covering for pelvic cavity• Middle – very muscular and contracts

(“contractions”) during childbirth in response to hormone oxytocin

• Inner – “Endometrium” – has two parts, one permanent, and one shed monthly if fertilization does not occur (“menstrual period”)

Female Internal Accessory Organs

• Uterus continued– The Uterus is divided into three vertical

sections:• 1. Fundus – top of the inverted “pear”• 2. Body – the majority of the “pear”• 3. Cervix – narrow end of the uterus that connects

to the vagina

*** Cervical Cancer is a common form of cancer for women, and can be detected in its early stages by Pap Smear; removal of the uterus may be required

Female Internal Accessory Organs

• Vagina– It is a fibromuscular tube approximately 9 cm long

that is angled– The Vagina is in front of the Rectum but behind the

Urinary Bladder– The Vagina, as it is a muscle, is able to extend to

allow for childbirth and sexual intercourse– The opening to the Vagina is initially enclosed by

tissue called the Hymen; it is usually ruptured by sexual intercourse but can also break due to other physical activities

Female Internal Accessory Organs

External Genitals

• There are four external genitals of the female:– 1. Labia Majora – large folds of skin– 2. Labia Minora – small folds of skin within the

Labia Majora– 3. Glans Clitoris – Sexually Sensitive/Pleasure

Organ– 4. Vestibular Glands – portion of skin that contains

the openings to the urethra and the vagina; in females the urethra and the vagina do not converge which is dissimilar to the convergence of the ejaculatory duct and the urethra in males

Female Reproductive Cycle

• Menstrual Cycle = “Period”– Puberty (11 to 13 years of age) signals the onset of

the Menstrual Cycle in females– Initially, a post pubescent female’s period is sporadic,

but as she ages, it becomes more frequent and consistent

– Within a few years after a female’s first period, her cycle will become regulated due to the presence of hormones, with her period lasting 7 days, and the time between each period lasting about 21 days = 28 day cycle

– Hormones such as Estrogen and Progesterone are extremely important in regulating a female’s reproductive cycle

Female Reproductive Cycle

Female Reproductive Cycle

• If fertilization and subsequent implantation occurs, HCG (Human Chorionic Gonadotropin) maintains the Corpus Luteum in the Ovary until the Placenta begins its own production of Estrogen and Progesterone

• Once the Placenta begins producing these hormones, the Pituitary Gland in the brain no longer sends messages to the ovary to produce more follicles until the pregnancy is complete

• These hormones also maintain the Endometrium throughout the pregnancy

Female Reproductive Cycle

• Menopause – The cessation of the female reproductive cycle– The hormones no longer are produced by the Pituitary

Gland to maintain the activity of the ovaries, and hence, there is no more potential for childbearing

– Usually occurs between the ages of 45 and 55– Symptoms are: hot flashes, dizziness, headaches,

insomnia, sleepiness, and depression

Female Reproductive SystemOverview

• https://www.youtube.com/watch?v=2_owp8kNMus

• https://www.youtube.com/watch?v=a8fgm-zEYjQ