Female Reproduction

Female Reproduction

Female Reproduction

The most important part of the female reproductive system are the ovaries

Two Functions of the Ovaries

Production of ova

Secrete hormones

Primary Follicles

At birth the ovaries contain many small sac like structures that contain immature ova called primary follicles

Primary Follicles

It is estimated that there are 200,000-400,00 primary follicles in each ovary at birth

Primary Follicles

It is estimated that there are 200,000-400,00 primary follicles in each ovary at birth

By age 50 most of them have degenerated.

Puberty

At age 8 the pituitary gland sends hormonal messages to the ovaries, stimulating them to release estrogen into the circulatory system.

Puberty

Between the ages of 11-14 the hormonal message becomes stronger thus bringing about the physiological changes known as puberty.

During this time the ovaries release estrogen into the circulatory system.

Estrogen

Estrogen is responsible for the primary and secondary sex characteristics.

Primary Sexual Characteristics

Increase in the size and physiological maturity of the fallopian tubes, uterus and vagina.

Secondary sexual characteristics

Sex desire

Body hair growth

Breast development

Feminine body features

Ovulation

Menstruation

Female Ovulation

Each month 15-20 immature follicles begin to grow and develop, usually one of these will balloon outward to full maturity. This one is called the graafian follicle.

Pituitary Gland

Simultaneous with the development of the stigma the pituitary gland increases its output of LH (Luteinizing Hormone)

Ovulation

LH causes the stigma to rupture causing ovulation.

Once ovulation has occurred the egg cell may be fertilized within 12-36 hours. After which it begins to degenerate.

Ovulation

The fallopian tubes gathers the egg by its fimbriated ends called ampulla and by the current created by the motion of the cilia.

Ovulation

Once ovulation has occurred the follicular remains are transformed into a temporary endocrine gland called the Corpus Luteum.

Ovulation

To prepare the reproductive system for the reception of the fertilized egg the corpus luteum secretes two important hormones: estrogen and progesterone

Hormones

Estrogen and progesterone are responsible for preparing the female reproductive system for reception of the fertilized egg.

Ovulation: Proliferative Phase

Initiated by estrogen causes a rapid growth of endometrial cells.

Ovulation Secretory Phase

Initiated by progesterone causing an increase in blood supply to the uterus

Acting together these hormones build and maintain the endometrium anticipating the reception of the fertilized egg.

Fertilization

If fertilization occurs the endometrium grows to a thick, blood vessel-rich, tissue layer. This represents an optimal environment for the implantation of a fertilized egg upon its arrival in the uterus.

Menstrual Phase

If fertilization fails to take place phase three of this recurring cycle is initiated:

Menstrual Phase: Approximately 24 hours prior to menstruation the blood supply to the uterus is shut off. In the absence of the blood supply the lining of the uterus endometrium dies. The dead tissue together with 1) a small quantity of blood in the uterine cavity initiates uterine contractions. These contractions expel the contents of the uterus as the menstrual flow.

The menstrual flow last approximately 7 days after which the cycle starts again.