Which Form 2220 Periods 2023-2024

To understand the various ways that medical science can assist reproduction, it is important to understand how the reproductive system functions in both sexes. The cause of infertility often lies equally with both men and women. The main players in the female reproductive cycle are the pituitary gland, the ovaries, and the uterus. Their activities are closely coordinated. Each month, one or other ovary releases a single egg, an event known as ovulation. It is brought about by a series of complex interactions between the pituitary gland, the ovaries, and the uterus. The pituitary gland is itself under the control of a small area of the brain known as the hypothalamus. A new menstrual cycle begins when the nerve cells of this center secrete a hormone called gonadotrophin-releasing hormone (GnRH) into the network of blood vessels which surrounds the pituitary gland. Stimulated by pulses of GnRH, cells in the pituitary gland secrete another hormone called follicle-stimulating hormone (FSH). FSH travels in the bloodstream, reaching the ovaries where it stimulates the formation and growth of an ovarian follicle in one or the other ovary. The follicle consists of an egg and a number of surrounding cells which secrete estrogen hormones and fluid. FSH helps the egg to mature and prepares it for release. As the follicle matures, the hypothalamus increases secretion of GnRH, which in turn stimulates the pituitary to secrete a second hormone, luteinizing hormone (LH). Towards the middle of the cycle, there is a sudden peak in the blood level of LH. This acts as the trigger for ovulation. Within minutes of its release, the egg is guided by suction through the fringed opening of the outer end of the fallopian tube, starting it on a journey which will take five or six days as it passes down the tube and finally reaches...