Ovulation & the menstrual cycle - Narrated 3D animation

to understand the various ways that medical science can assist reproduction it is important to understand how the reproductive system functions in both sexes because 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 this 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 gonadotrophins releasing hormone GnRH into the network of blood vessels which surrounds the pituitary gland stimulated by pulses of gonadotrophins releasing hormone cells in the pituitary glands secrete another hormone follicle-stimulating hormone or FSH FSH travels in the bloodstream reaching the ovaries there it stimulates the formation and growth of an ovarian follicle in one or other ovary the follicle consists of an egg 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 this in turn stimulates the pituitary to secrete a second hormone which acts on the ovary this is luteinizing hormone or LH toward 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 the cavity of the uterus meanwhile after the follicle ruptures it is converted into this yellowish body known as the corpus luteum cells at the corpus luteum secrete the hormone progesterone which brings about important changes in the lining of the uterus preparing it for possible pregnancy in fact the lining of the uterus known as the endometrium undergoes changes in response to hormone levels during the cycle in the first half of the cycle known as the follicular phase the developing follicle secretes increasing amounts of estrogen hormone which encourages regeneration of the endometrium after ovulation there are important changes in the endometrium aimed at making it suitable to receive a fertilized egg these changes are brought about by a secretion of progesterone from the corpus luteum the secretion of progesterone is maintained for several days but if the egg is not fertilized in that time the corpus luteum withers and falling levels of progesterone and estrogen trigger the shedding of the uterine lining as the menstrual flow the cycle then starts again but if the egg is fertilized no menstruation occurs as the corpus luteum continues to function secreting progesterone during the first three months of the pregnancy thereafter numerous changes occur to support the developing embryo

Channel: FrizzBzzirF

Views: 4,057,878

Keywords: the, reproductive, system, menstrual, cycle, ovulation, pregnancy, 3D, medical, animation, baby, health, mother, follicle, ovary, sperm, fertilization, fallopian, tube, egg, uterus, menstruation, human, body, eostrogen, period, medicine, educational, physiology, endocrine, hypothalamus, pituitary, Hormone

Id: WGJsrGmWeKE

Length: 4min 5sec (245 seconds)

Published: Fri Jun 03 2011