The Reproductive System

What is the Reproductive System? The reproductive system is the organs and glands that allow new humans to be formed. This is the only system that humans can be healthy if it is absent or defective.

Sexual Development Sexual development begins in the 7th week of gestation. If a fetus is male, a gene on the Y chromosome tells the tissue to develop into a testes. The testes begins to produce testosterone. Testosterone causes the male fetus to develop male reproductive organs.

Sexual Development If the fetus is female, there is no Y chromosome. The tissue develops into an ovary which produces estrogen. Estrogen causes the fetus to develop female reproductive organs.

Sexual Development Puberty – a period of rapid physical growth during which the reproductive system becomes fully functional. Happens between ages 9-15 Girls tend to enter puberty one year earlier than boys. Caused by a release of FSH and LH.

Male Reproductive System Release of FSH and LH cause males to produce large amounts of testosterone which triggers sperm production in the testes. Scrotum: Sac that contains the testes. Testes – Male reproductive gonad that produces sperm

Male Reproductive System Epididymis – Structure behind the testis that stores sperm while it matures fully. Vas deferens – tube that connects the testes to the urethra through the abdominal cavity and transports sperm.

Male Reproductive System Prostate- gland that wraps around the urethra. Produces seminal fluid to keep sperm alive. Penis – external male reproductive organ

Female Reproductive System FSH and LH cause the ovaries to produce large amounts of estrogen and ovulate eggs. Ovary – female reproductive gonad where follicles mature into eggs. Fallopian Tubes – cilia-lined tube that connects the ovary to the uterus.

Female Reproductive System Uterus - muscular organ where a fertilized egg can develop. Cervix –the lower portion of the uterus that connects to the vagina. Vagina – canal that connects the uterus to the outside of the body

The Menstrual Cycle A repeating cycle of changes as the reproductive system prepares for the release of an egg. Four phases: Follicular Ovulation Luteal Menstruation

The Menstrual Cycle Follicular phase: Ovulation One or more follicles in the ovary prepare to release an egg. The lining of the uterus thickens to prepare for a fertilized egg. Ovulation The egg is released from the ovary and enters the fallopian tube.

The Menstrual Cycle Luteal phase: The ruptured follicle pumps out large amounts estrogen and progesterone for several days then stops. Uterine lining becomes fully mature. If the embryo does not implant, the lining begins to detach from the uterus as the hormone level falls.

The Menstrual Cycle Menstruation Shedding of the uterine lining. The first day of the menstrual cycle is the first day of menstruation. Pregnancy dates are determined from the first day of the woman’s last menstrual cycle.