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Explore the fascinating process of human reproduction from sperm production and egg fertilization to pregnancy development and childbirth. Learn about the male and female reproductive systems, pregnancy stages, fetal development, maintaining a healthy pregnancy, childbirth stages, and potential birth complications.
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Reproduction • Reproduction is the process by which organisms produce offspring
Male Reproductive System • Sperm = reproductive cells of males • Functions of the male reproductive system are to produce sex hormones, to produce & store sperm, and to deliver sperm to the female reproductive system • Keeping healthy: • Cleanliness • Sexual abstinence • Protection from trauma • Self-exams
Female Reproductive System • -Eggs, or ova, are the reproductive cells in women • The functions of the female reproductive system are to produce sex hormones, to produce eggs, and to provide a nourishing environment in which a fertilized egg can develop into a baby • Keeping healthy: • Cleanliness • Sexual abstinence • Prompt treatment for infections • Self-exams
Pregnancy • 1) Fertilization • Only a few hundred of the hundreds of million of sperm that enter the vagina usually make it to the egg • Only one sperm can fertilize the egg • Within seconds after fertilization occurs, the surface of the egg changes so that no more sperm can enter the egg • In the 1st week after fertilization, the fertilized egg undergoes many cell divisions & travels to the uterus
Pregnancy • 2) Zygote • The united sperm & egg is called a zygote • Within 36 hours, while the zygote is still traveling through the fallopian tube, it begins to divide
Pregnancy • 3) Cell Division • From the two-cell stage until about 9 weeks after fertilization, the growing structure is called an embryo
Pregnancy • 4) Blastocyst • About 5 days after fertilization, the embryo reaches the uterus, where it floats free for a few days • This ‘clump’ of cells is called a blastocyst
Pregnancy • 5) Implantation • Once the blastocyst forms, it begins to attach itself to the wall of the uterus
Development in the Uterus • Amniotic sac • Fluid-filled bag of thin tissue that develops around the embryo • Placenta • The attachment holding the embryo to the wall of the uterus; oxygen and nutrients move from mother’s blood into the placenta • Umbilical cord • Develops between the embryo & placenta; embryo’s lifeline; blood vessels inside carry oxygen & nutrients to growing embryo
Development in the Uterus • During the first 2 months, major body systems and organs begin to form • By the end of 8 weeks, the embryo is about an inch long & has recognizable features like arms, legs, ears & eyes • From the 3rd month until birth, the unborn child is called a fetus
Healthy Pregnancy • Getting proper nutrition & exercise and avoiding drugs & environmental hazards are especially important before & throughout pregnancy • Pregnant women only need to eat about 300 extra calories a day • Folic acid is a very important vitamin • It helps develop the neural tube, which will turn into the spinal cord
Healthy Pregnancy • A pregnant woman should talk to her doctor before using any prescription or over-the-counter drugs, including pain medications, creams & lotions and vitamins • Environmental hazards: • Xrays • Lead • Mercury • Cat litter
Child Birth • 1) Labor • The work performed by the mother’s body to push the fetus out • For a 1st child, labor can last 2-24 hours or longer • Contractions of the muscles of the uterus cause the cervix to dilate, or expand • Near the end of this stage, the amniotic sac breaks
Child Birth • 2) Delivery of baby • This stage can take from 30 minutes to more than 2 hours • Contractions continue & the baby is pushed out • Once the baby is out, the doctor clamps & cuts the umbilical cord • Baby is looked over, and it’s vital signs are listened to
Child Birth • Delivery of after birth • Even though the baby is born, the birth process is not complete • Contractions push out the placenta during this third stage • This lasts only about 15-30 minutes
Complications at Birth • Stillbirth: Occurs when a fetus dies and is expelled from the body after the 20th week of pregnancy • Cesarean section: C-section; surgical method of birth; incision in lower abdomen to uterus • Premature birth: delivery of a live baby before the 37th week of pregnancy; the earlier the birth, the more problems the baby tends to have; organs may not be fully developed
Multiple Births • Identical twins • Twins that develop from a single fertilized egg; are the same sex & have the same inherited traits since they are from the same zygote • Fraternal twins • Sometimes two eggs are released from the ovary & are fertilized by two sperm; are no more alike than siblings; may or may not be the same sex • Triplets or more • Are less common than twins