Reproductive System

In the womb, the baby's body is covered by a thin layer of hair but as soon as the baby is born it disappears. The largest cell in the female human body is the ovum or egg present in the ovaries About 500 million sperm mature every day in a normal male adult. The ovaries of a newborn girl contains about 600,000 immature eggs. The average life span of a sperm is about 36 hours. The life span of an ova is about 12 - 24 hours. The female human body is capable of giving birth to 35 children in one lifetime.

Male Reproductive Structure Testes: produces gametes Seminiferous tubules: where sperm is formed

Sperm Start to produce during puberty Goes through meiosis (diploid to haploid) Three parts Head: contains enzymes to help penetrate the egg & chromosomes Midpiece- mitochondria (energy) Tail (flagellum)- propels the sperm

Pathway of Sperm

Female Reproductive Structure Ovaries: produces gametes Fallopian tube: leads to the uterus; where fertilization takes place Uterus: where fertilized egg develops

Egg Born with over 400,000 eggs but only 300 to 400 mature. Forms through meiosis (haploid; 23 chromosomes)

Gestation Gestation: human development (~9 months) Sperm & egg fuse together creating a zygote Implantation- attaches to the uterus & pregnancy begins

Pregnancy- 3 trimesters 1st trimester Most changes occur Embryo- 1st eight weeks Nervous system begins forming All organ systems begin to form Heart starts to beat

Pregnancy 2nd trimester Fetus- 8 weeks until birth Mother’s uterus enlarges Fetal skeleton forms Mom can feel the fetus move Hair forms (lanugo) Heartbeat can be heard Swallows, sucks thumb,

Pregnancy 3rd trimester Fetus grows quickly Can see light Can react to sounds Develops fat deposits under skin

Birth Smooth muscles of the uterus contract Amniotic sac breaks (breaking water) Labor- muscular contraction and other events leading to the birth Fetus is pushed out Afterbirth- placenta expelled