Female Reproductive System Chapter 50 April Sike

Summary The female reproductive system has two ovaries, two fallopian tubes, the uterus, and the vagina The ovaries produce eggs. The egg is released from the ovary into a fallopian tube and swept into the uterus by cilia and muscle action.

Evolutionary development The evolution of the reproductive system is unknown. No one has been able to explain the origin of the intricate development of the embryo. Evolutionary theorists ask us to believe that random, chance occurrences brought about this process, but the idea that it “just evolved” is unworthy of consideration or acceptance.

Necessary For producing female eggs needed for reproduction. For transporting the ova to the site of fertilization. Reproduction is needed to create offspring, and to keep the evolutionary chain going.

Ovaries The ovaries are oval shaped glands on both sides of the uterus. They produce eggs and hormones.

Fallopian Tubes Also called uterine tubes or oviducts. Narrow tubes that are attached to the upper part of the uterus. They transport ova from the ovaries to the uterus. Fertilization of an egg by a sperm, usually occurs in the fallopian tubes.

Uterus The uterus is a muscular, pear-shaped organ that is the home to a developing fetus. It is divided into two parts; The cervix- the lower part that opens into the vagina. The corpus- the main body of the uterus. It can easily expand to hold a developing baby.

Vagina An elastic, muscular canal with soft, flexible lining. The vagina connects the uterus to the outside of the body. It's where the penis is inserted during sexual intercourse. It's the pathway that a baby takes out of a woman's body during childbirth, called the birth canal. It provides the route for the menstrual blood (the period) to leave the body from the uterus.

The Menstrual Cycle At birth, a female's ovaries contain about 1 million follicles. Follicles contain maturing ovum. Each follicle has begun meiosis but stops in prophase. At this stage the ova are called primary oocytes. Some of these oocyte-containing follicles are stimulated to develop during each cycle. The human menstrual cycle lasts approximately one month(28 days).

Follicular Phase The first half of the menstrual cycle. Also known as the pre-ovulation phase because it is the hormonal changes that happen during this time that prepare the body for ovulation. This phase can last 13 to 18 days.

The pituitary gland releases FSH (follicle stimulating hormone), that causes the ovarian follicles to develop. Eventually one of the follicles becomes dominant and releases an egg. The maturing of the dominant follicle leads to the increase in the hormone estrogen. This causes cervical mucus to form and help the movement of sperm, and thickens the lining of the uterus.

Ovulatory Phase Ovulation usually occurs mid-cycle depending on the length of the follicular phase. Once estrogen reaches a certain level, it signals the pituitary gland that the egg is ready to be released by the dominant follicle. The pituitary gland then makes the hormone LH (luteinizing hormone) that triggers ovulation. The egg is released into the fallopian tube where it is ready to be fertilized by sperm.

Luteal Phase The corpus luteum is the now empty dominant follicle that released the egg. After ovulation it releases the hormone progesterone, which maintains the receptive uterine environment in case of fertilization and implantation.

Fertilization and Implantation If the egg is fertilized and implants in the uterus, then the corpus luteum will keep making progesterone to nourish the embryo until the placenta starts to develop. If the egg is not fertilized and does not implant, than the corpus luteum will disintegrate after two weeks, causing progesterone levels to drop and signal the start of a new cycle.

Fertilization Fertilization happens by the bottom of the fallopian tube. Fertilization is when a sperm penetrates the egg. After the egg is fertilized it travels to the uterus to be implanted.

Implantation Implantation is when an egg attaches to the inside of the uterus.

Interdependence The endocrine system releases hormones that influence every cell, organ, and function of our bodies. It regulates mood, growth and development, tissue function, and metabolism, as well as sexual function and reproductive processes.

Major glands include the hypothalamus, pituitary, thyroid, parathyroid, adrenals, pineal body, and the reproductive glands, which include the ovaries. Ovaries secrete estrogen and progesterone. Estrogen is involved in development of female sexual features. Estrogen and progesterone are both involved in pregnancy and the regulation of the menstrual cycle.

Disorders and diseases

Sexually transmitted infections (STIs). These include pelvic inflammatory disease (PID), human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), human papillomavirus (HPV, or genital warts), syphilis, Chlamydia, gonorrhea, and genital herpes (HSV). Most are spread from one person to another by sexual contact.

Ectopic pregnancy Occurs when a fertilized egg does not travel into the uterus, but grows in the fallopian tube. This can cause severe abdominal pain, and usually requires surgery.

Endometriosis Occurs when tissue found in the uterus starts to grow outside of the uterus, like in the ovaries, fallopian tubes, or other parts of the pelvic cavity. It causes abnormal bleeding, painful periods, and general pelvic pain.

Polycystic ovary syndrome A hormone disorder where too many male hormones (androgens) are made by the ovaries. This causes the ovaries to become enlarged and develop fluid-filled sacs, or cysts. It usually appears during the teen years. Depending on the type of condition. It can be treated with drugs to regulate hormone balance and menstruation.