reproductive system science7

The Reproductive

System

• Reproduction is the process that continues life on earth

• Males and females each have structures specialized for their roles in reproduction

• The male reproductive system consists of both external and internal organs

• The main external (outside the body) organs are the penis and the scrotum

• The scrotum contains the testes, which produce the hormone testosterone

• The testes also produce male reproductive cells called sperm

• Each sperm consists of a head and a tail; the head contains hereditary information and the tail moves it

• Semen is the mixture of sperm and fluid that helps move reproductive cells through the urethra and out of the body

• The internal parts of the male reproductive system include:

• vas deferens, a long, muscular tube that travels from the epididymis (a long tube that rests on the back of each testicle) into the pelvic cavity.

• The vas deferens transports mature sperm to the urethra

• Female reproductive organs are internal

• Ovaries are the female reproductive organs that produce eggs, the female sex cells

- When a female is born, she already has all the cells that will become eggs

• Ovulation is a process in which an egg is released, about once every month. The two ovaries release eggs on alternating months

• The uterus is a muscular organ with thick, protective walls

• A fertilized egg develops in the uterus (aka womb)

• Fertilization is the joining of egg and sperm

• The cervix is the lower end of the uterus; it is directly connected to the birth canal (vagina)

• It is through the birth canal that a baby travels from the womb to the outside world.

• The menstrual cycle is the monthly cycle of changes in the female reproductive system.

• This cycle is controlled by hormones, which begin by developing eggs in the ovary.

• Hormones also cause the lining of the uterus to become thicker, in preparation for the possibility of protecting and nourishing a baby

• Ovulation occurs about 14 days before menstruation begins; once an egg is released, it must be fertilized within 24 hours or it begins to break down

• If the egg is not fertilized, the lining of the uterus breaks down. Blood and tissue cells are released in menstrual flow.

• The entire menstrual cycle averages 28 days, though this can vary

• The average age at which menstrual cycles begin is 12 or 13 years, though this can vary widely.

• The cycle continues until around age 50 or 51 (again, this varies). (these years between are called a woman’s reproductive years)

• Menopause occurs when both ovulation and menstrual periods end

• In years right before menopause, hormone production begins to shut down and changes in the cycle occur. This time is called perimenopause