Female Reproductive System Andrew Coco Paige Griffin Josie Matosky

Introduction The reproductive system or genital system is a system of organs within an organism which work together for the purpose of reproduction.

Introduction The female reproductive system consists of the external and internal genital organs. Many parts of the brain are involved in the reproductive system also. Hypothalamus pituitary gland adrenal glands

External Organ List The area containing these organs is called the vulva. Mons pubis Labia Majora Labia minora Bartholin's glands Clitoris

External Organs The external genital organs have three main functions: Enabling sperm to enter the body Protecting the internal genital organs from infectious organisms Providing sexual pleasure

Mons Pubis The mons pubis is a rounded mound of fatty tissue that covers the pubic bone. During puberty, it becomes covered with hair. The mons pubis contains oil-secreting (sebaceous) glands that release substances that are involved in sexual attraction (pheromones).

Labia Majora The labia majora (literally, large lips) are relatively large, fleshy folds of tissue that enclose and protect the other external genital organs. They are comparable to the scrotum in males. The labia majora contain sweat and sebaceous glands, which produce lubricating secretions. After puberty, hair appears on the labia majora.

Labia Minora The labia minora (literally, small lips) can be very small or up to 2 inches wide. The labia minora lie just inside the labia majora and surround the openings to the vagina and urethra. A rich supply of blood vessels gives the labia minora a pink color. During sexual stimulation, these blood vessels become engorged with blood, causing the labia minora to swell and become more sensitive to stimulation

Introitus The opening to the vagina is called the introitus. The vaginal opening is the entryway for the penis during sexual intercourse and the exit for menstrual blood and vaginal discharge as well as a baby. When stimulated, Bartholin's glands (located beside the vaginal opening) secrete a thick fluid that supplies lubrication for intercourse. The opening to the urethra, which carries urine from the bladder to the outside, is located above and in front of the vaginal opening.

Clitoris The clitoris, located between the labia minora at their upper end, is a small protrusion that corresponds to the penis in the male. The clitoris, like the penis, is very sensitive to sexual stimulation and can become erect. Stimulating the clitoris can result in an orgasm.

Internal Organs The internal genital organs form a pathway (the genital tract). This pathway consists of the following Vagina Uterus Fallopian tubes (oviducts) Ovaries

Vagina The vagina is a narrow, muscular but elastic organ about 4 to 5 inches long in an adult woman. It connects the external genital organs to the uterus. The vagina is the main female organ of sexual intercourse. It is the passageway for sperm to the egg and for menstrual bleeding or a baby to the outside.

The vagina is lined with a mucous membrane, kept moist by fluids oozing from cells on its surface and by secretions from glands in the cervix (the lower part of the uterus). A small amount of these fluids may pass to the outside as a clear or milky white vaginal discharge, which is normal. During a woman's reproductive years, the lining of the vagina has folds and wrinkles.

Uterus The uterus is a thick-walled, muscular, pear- shaped organ located in the middle of the pelvis, behind the bladder, and in front of the rectum. The uterus is anchored in position by several ligaments. The main function of the uterus is to sustain a developing fetus. The uterus consists of the cervix and the main body (corpus).

Cervix The cervix is the lower part of the uterus, which protrudes into the upper end of the vagina. It can be seen during a pelvic examination. Like the vagina, the cervix is lined with a mucous membrane, but the mucous membrane of the cervix is smooth.

Uterus and Cervix Sperm can enter and menstrual blood can exit the uterus through a channel in the cervix. The channel is usually narrow, but during labor, the channel widens to let the baby through. The cervix is usually a good barrier against bacteria, except around the time an egg is released by the ovaries (ovulation), during the menstrual period, or during labor. Bacteria that cause sexually transmitted diseases can enter the uterus through the cervix during sexual intercourse.

Fallopian Tubes The two fallopian tubes, which are about 2 to 3 inches (about 5 to 7 centimeters) long, extend from the upper edges of the uterus toward the ovaries. The tubes do not directly connect with the ovaries. Instead, the end of each tube flares into a funnel shape with fingerlike extensions (fimbriae). When an egg is released from an ovary, the fimbriae guide the egg into the relatively large opening of a fallopian tube.

Ovaries The ovaries are usually pearl-colored, oblong, and about the size of a walnut. They are attached to the uterus by ligaments. In addition to producing female sex hormones and male sex hormones, the ovaries produce and release eggs. The developing egg cells (oocytes) are contained in fluid-filled cavities (follicles) in the wall of the ovaries. Each follicle contains one oocyte.

Puberty Puberty is a sequence of events in which physical changes occur, resulting in adult physical characteristics and capacity to reproduce. These physical changes are regulated by changes in the levels of hormones that are produced by the pituitary gland—luteinizing hormone and follicle- stimulating hormone.

Puberty The first change of puberty is usually the start of breast development Shortly afterward, pubic and underarm hair begin to grow. The growth spurt accompanying puberty typically begins about when pubic and underarm hair begin to grow.

Menstrual Cycle Menstruation is the shedding of the lining of the uterus (endometrium) accompanied by bleeding. It occurs in approximately monthly cycles throughout a woman's reproductive life, except during pregnancy. Menstruation starts during puberty and stops permanently at menopause

Menstrual Cycle By definition, the menstrual cycle begins with the first day of bleeding, which is counted as day 1, and lasts about 28 days. Menstrual bleeding lasts 3 to 7 days, averaging 5 days. Blood loss during a cycle usually ranges from ½ to 2½ ounces.

Menstrual Cycle Regulation The menstrual cycle is regulated by hormones. Luteinizing hormone and follicle-stimulating hormone, which are produced by the pituitary gland, promote ovulation and stimulate the ovaries to produce estrogen and progesterone Estrogen and progesterone stimulate the uterus and breasts to prepare for possible fertilization.

Diagram of the phases of the menstrual cycle

Phases of Menstrual Cycle The cycle has three phases: follicular (before release of the egg), ovulatory (egg release), and luteal (after egg release).

Follicular Phase This phase begins on the first day of menstrual bleeding (day 1). But the main event in this phase is the development of follicles in the ovaries. On average, the follicular phase lasts about 13 or 14 days

Ovulatory Phase This phase begins when the level of luteinizing hormone surges. Luteinizing hormone stimulates the dominant follicle to bulge from the surface of the ovary and finally rupture, releasing the egg. The ovulatory phase usually lasts 16 to 32 hours. It ends when the egg is released.

Luteal Phase This phase begins after ovulation. It lasts about 14 days (unless fertilization occurs) and ends just before a menstrual period. In this phase, the ruptured follicle closes after releasing the egg and forms a structure called a corpus luteum, which produces increasing quantities of progesterone. If the egg is not fertilized, the corpus luteum degenerates after 14 days, and a new menstrual cycle begins.

Fertilization

Fertilization fusion of gametes to produce a new organism. Human fertilization is the union of a human egg and sperm, usually occurring in the fallopian tube. It is also the initiation of prenatal development.

Fertiliaztion Upon encountering the ovum, the acrosome of the sperm produces enzymes which allow it to burrow through the outer jelly coat of the egg. The sperm plasma then fuses with the egg's plasma membrane, the sperm head disconnects from its flagellum and the egg travels down the Fallopian tube to reach the uterus.

Corona radiata The egg and the sperm bind through the corona radiata, a layer of follicle cells on the outside of the secondary oocyte. Fertilization occurs when the nuclei of a sperm and an egg fuse. The successful fusion of gametes form a new organism.

Zona pellucida After binding to the corona radiata the sperm reaches the zona pellucida, which is an extra- cellular matrix of glycoproteins. A special complementary molecule on the surface of the sperm head binds to a ZP2 glycoprotein in the zona pellucida.

Cortical reaction Once the sperm cells find their way past the zona pellucida, the cortical reaction occurs Cortical granules inside the secondary oocyte fuse with the plasma membrane of the cell, causing enzymes inside these granules to be expelled by exocytosis to the zona pellucida.

Cortical reaction This in turn causes the glyco-proteins in the zona pellucida to cross-link with each other, making the whole matrix hard and impermeable to sperm. This prevents fertilization of an egg by more than one sperm.

Pregnancy After the joining of the sperm and egg cell, the female carries the child inside her womb for approximately 40 weeks after conception

Development of fetus