34.1 Reproductive Anatomy

Reproductive System It is a collection of specialized organs, glands, and hormones that help to produce a new human being. Puberty: a time in the life of the individual when sexual maturity begins. LH and FSH are released by the pituitary gland to start the development of sexual characteristics.

Female Reproductive system

Function To produce ova (singular, ovum) or egg cells and to provide a place for the fertilized egg to develop.

Female Reproductive Structures

Structures All the female reproductive structures are located inside the body to protect the fertilized egg while it develops. Ovaries: produce the eggs. (2, one on each side of the uterus) Babies are born with around 2 million immature egg cells in the ovaries. Fallopian tubes: tubes that end in the uterus. The egg takes several days to travel through this tube. A sperm might fertilize it during this time.

Uterus: womb; sac where the fertilized egg develops into a fetus. It is pear- shaped. Composed of 3 layers: thin inner layer of epithelium Thick middle layer of muscle An outer layer of connective tissue

If the egg is not fertilized by the time it reaches the uterus, it is broken down and discarded. If it is fertilized, it will stick to the walls of the uterus. Cervix: lower end of the uterus. It opens into the vagina. Vagina: a muscular tube through which the baby will be pushed.

Hormones LH released by the pituitary gland and stimulates the ovaries to release estrogen and progesterone. FSH released by the pituitary gland and stimulates the release of the egg from the ovary. Estrogen: Functions: Controls the development of female sexual characteristics (ex: widening of hips, breast size) Needed for maturation of egg before it leaves the ovary. Helps to prepare the uterus for pregnancy each month and to maintain pregnancy.

Male reproductive system

Function To produce sperm and to deliver them to the female reproductive system. Males start producing sperm starting puberty and for the rest of their lives.

Structure Testes: paired organs that produce sperm. Each testis contains hundreds of tiny tubules called seminiferous tubules where millions of sperm are produced. Scrotum: the pouch that hangs below the pelvis and that contains the testes. It keeps the testes two to three degrees cooler than the core body temperature, allowing the sperm to develop.

Testes have to descend into the scrotum before birth because it is 3 degrees cooler than the abdomen. The cooler temperature is needed for proper sperm production.

Epididymis: a long coiled tube that receives the immature sperm from the testes and stores them until they are mature. Vas deferens: a long duct sperm goes through during sexual stimulation.

Three glands secrete fluids into the vas deferens to nourish and protect the sperm. Prostate gland- secretes fluid to help sperm move easily Bulbourethral gland- secretes base to neutralize acidity in the urethra and female vagina. Seminal vesicles- secretes base to neutralize acidity in the urethra and female vagina. Sperm+ fluid = semen (milky white substance)

Path of sperm Sperm moves from the testes, to the epididymis, then to the vas deferens. The fluids will mix with it forming semen. Semen then moves into the urethra and out of the penis during ejaculation. Upon sexual arousal, blood will flow into the penis, making it rigid. Smooth muscle contractions move the semen along the urethra and expel it out of the penis.

Hormones LH released by the pituitary gland stimulates the release of testosterone from the testes. Testosterone: steroid hormone that: stimulates production of sperm cells. (along with FSH) controls the development of male sexual characteristics (deep voice, more hair)