Human Reproduction and Development

Female Reproductive System 1. Ovaries (2) a) produce egg cells (gametes) b) produce hormones estrogen and progesterone 2. Oviducts – tubes leading from ovaries to uterus. Egg fertilized in oviducts. 3. Uterus – where embryo implants and develops. Placenta forms here.

4. Birth Canal (vagina) – site where sperm enters and swim to oviduct. Also the passageway for the baby. Male Reproductive System 1. Testes a) produces sperm cells (gametes) b) produces the hormone testosterone 2. Prostate – produces fluid (semen) needed for delivery of gametes to female.

3. Urethra – passage for sperm to leave the body. (also part of excretory system) 4. Penis – delivers sperm to female reproductive tract.

Role of Hormones Female: 1. Estrogen – egg formation female secondary sex characteristics like wider pelvis and breast development. Prepares uterus for pregnancy

2. Progesterone – prepares uterus for pregnancy. Maintains the lining of uterus during pregnancy. Male: 1. Testosterone – stimulates sperm development, secondary sex characteristics like facial hair, deep voice.

Female Reproductive Cycle

Cycle = 28 days Follicle surrounding an egg in ovary develops and matures (follicle stage) Egg released around day 14 (ovulation) If egg not fertilized, uterine lining disintegrates and is released (menstruation)

Zygote Formation  1. Fertilization – in oviducts  2. Implantation 6-10 days later, embryo implants in uterine lining.

Embryo Formation 1. Cleavage – repeated cell divisions of zygote.

2. Growth – increase in cell size and number 3. Differentiation cells specialize into separate tissues and organs.

Internal Development Umbilical Cord – attached to uterine wall - brings nutrients to embryo - carries wastes away(CO2)

Placenta - rich in mother’s and baby’s blood vessels - nutrients and wastes diffuse between mother’s and baby’s vessels

Amnion – fluid filled sac that surrounds and protects embryo. Most mammals have internal development of the fetus with a placenta to nourish them. Internal fertilization in land animals is an adaptation for successful reproduction without water.

External Fertilization External fertilization and development is found in water animals.

Reproductive Technology 1. Cloning – making identical copies of plants and animals with preferred genes. 2. Artificial Insemination – injecting sperm into a female without the male being present. 3. In Vitro fertilization – removing an egg and combining it with sperm outside of a female.

Amniocentesis – removing cells from amniotic fluid while baby still inside the uterus to analyze them.