The Reproductive Cycle
What is the Corpus Luteum?
A Corpus Luteum is a structure formed by a follicle that has shed its ovum. The word Corpus Luteum means "yellow body". It develops from a Graafian follicle after ovulation. If fertilization occurs, the corpus luteum produces the hormone progesterone. This helps prepare the uterus for implantation. If fertilization does not occur, then the corpus luteum starts to break down about 10 days after ovulation, a couple days after the last days of menstruation.
What is the Reproductive Cycle?
A woman's reproductive cycle prepares her body to nurture new life. In a series of steps, it triggers the release of an egg cell and creates the right environment in which the egg can develop. The female reproductive cycle has two interlinked parts, the ovarian cycle and the menstrual cycle.
What is Menstruation?
When menstruation occurs, the thickened lining of the uterus is shed, and its cells and blood flow out of the vagina. Menstruation normally lasts for about 5-7 days. This part of the menstrual cycle is commonly known as a period.
What is a Follicle?
A follicle is a ball-shaped cluster of cells containing a ingle ovum, or egg. This follicle then nourishes and protects the ovum from damage. This Primary Follicle then changes into a Secondary Follicle, which contains fluid. Eventually, one of these follicles will become so large that is forms a blister-like swelling, called a Graafian Follicle. At the moment of ovulation, the Graafian Follicle will burst. The ovum is swept into the Fallopian Tube and toward the uterus.
What is Menarche?
This is the beginning of the Menstrual Cycle. Most girls have their period at about twelve years of age. This is called Menarche (Men-arky). From this moment, a girl's reproductive system functions fully although her body has not yet reached its final adult form.
What is Menopause?
Menopause is the point when the menstrual cycle comes to an end and no longer functions. This usually happens in women at ages 45-55, also known as middle age. Menopause is caused by changes in the levels of sex hormones present in the body.
What is the Ovarian Cycle?
Once a girl reaches puberty, her ovaries begin to release egg cells, at a steady rate, usually every 28 days. Sometimes more than one ovum can be released, and this can result in twins or triplets. This cycle starts when the pituitary gland releases a "FHS", or a Follicle Stimulating Hormone. This triggers the development of follicles in the ovaries. Another pituitary hormone, luteinizing hormone, then stimulates ovulation. If the ovum or ova are not fertilized, the cycle then repeats.
What is Ovulation?
Ovulation is the release of an ovum.
What is the Menstrual Cycle?
The Menstrual Cycle is the changes in the lining of the uterus and lasts for about 28 days. The endometrium thickens to receive an egg cell, but the lining breaks down if the egg does not implant. This cycle starts when the primary follicles release estrogen, thickening the endometrium. After ovulation, the release of an egg cell, progesterone from the corpus luteum increases the blood supply to the endometrium. If an egg implants, the cycle stops until after birth. If implantation does not occur, the lining and the egg are shed, and the cycle starts once again.
