Human Reproduction Male and Female Reproductive Anatomy

Importance of Reproduction Insures the survival of a species Insures the survival of a species Involves the fusion of male and female gametes to produce new genetic combinations Involves the fusion of male and female gametes to produce new genetic combinations Humans have separate male and female reproductive systems: Humans have separate male and female reproductive systems: 1. Male gonads: testes produce cells called sperm 2. Female gonads: ovaries produce cells called eggs The fusion of male and female sex cells is a process called fertilization The fusion of male and female sex cells is a process called fertilization Zygote  Embryo  Fetus Zygote  Embryo  Fetus

Female Sex Cells: Eggs Female gamete Female gamete Contains nucleus and stored food called yolk (used as nourishment for the developing animal) Contains nucleus and stored food called yolk (used as nourishment for the developing animal) Egg cells are microscopic (0.1mm in diameter Egg cells are microscopic (0.1mm in diameter

Male Sex Cells: Sperm Also microscopic (but times smaller then an egg) Also microscopic (but times smaller then an egg) Has a head, a mid-piece, and a tail Has a head, a mid-piece, and a tail Streamlined with only a small amount of cytoplasm surrounding the nucleus Streamlined with only a small amount of cytoplasm surrounding the nucleus Head: nucleus which contains the chromosomes, and an acrosome which is filled with special enzymes that dissolve the outer coating surrounding the egg and thus penetrate the egg Head: nucleus which contains the chromosomes, and an acrosome which is filled with special enzymes that dissolve the outer coating surrounding the egg and thus penetrate the egg Mid-piece: packed with mitochondria which provide energy so that the sperm can move Mid-piece: packed with mitochondria which provide energy so that the sperm can move Flagellum: long whip-like tail which enables the sperm to swim through liquids Flagellum: long whip-like tail which enables the sperm to swim through liquids

Male System – ventral view

Male System – front view

Male Reproductive System Seminiferous tubules - produces immature sperm cells Seminal vesicle - secretes fructose into the semen, which provides energy for the sperm Epididymis - matures and stores sperm cells in coiled tubules Testes - produces sperm cells - produces the hormone testosterone Vas Deferens - carries sperm from the epididymis to its junction with the urethra

Male Reproductive System Cont. Cowper’s gland - secretes mucous-rich fluids into the semen that may protect the sperm from acids in the urethra Prostate gland - secretes an alkaline buffer into the semen to protect the sperm from the acidic environment of the vagina Penis - deposits sperm into the vagina during ejaculation - contains the urethra Urethra - carries semen during ejaculation - carries urine from the bladder to the exterior of the body

Female System – side view

Female System – ventral view

Female Reproductive System Ovaries - produces the hormones estrogen and progesterone - site of ova (egg cell) development and ovulation Fimbria - sweep the ovum into the oviduct following ovulation Fallopian tubes (oviducts) - carry the ovum from the ovary to the uterus - usually the site of fertilization

Female Reproductive System Cont. Vagina - extends from the cervix to the external environment - provides a passageway for sperm and menstrual flow - functions as the birth canal Uterus (womb) - Involved in menstruation - Pear-shaped organ in which the embryo and the fetus develop Cervix - separates the vagina from the uterus - holds the fetus in place during pregnancy - dilates during birth to allow the fetus to leave the uterus