Human Growth and Development Lesson 2 Fertilization to

Human Growth and Development Lesson 2 Fertilization to Birth

Fertilization – union of a sperm and egg is called a zygote As the cell divides, it is called a blastocyst

Fertilized egg implants in the wall of the uterus

Embryo = an implanted fertilized egg 4 th week = heart begins to beat 6 th week = internal organs develop

Fetus 8 weeks after fertilization

Development in the womb

First Trimester • 4 weeks – Heart begins to beat • 10 weeks – Functioning internal organs & arms, legs and feet have formed • 11 weeks – Fetus can swallow, hiccup and make a fist • 12 weeks – Ultrasound can determine whether the child is male or female

Second Trimester • 14 weeks – movement is felt by the mother • 18 weeks – fetus reacts to sound • 23 weeks – taste buds are formed • 24 weeks – eyebrows, eyelashes are well formed • After 24 weeks…some fetuses born prematurely can survive with special medical care

Third Trimester • 29 weeks – fetus practices breathing • 35 weeks – organs are fully functional • 37 weeks – fully developed baby ready to be born

End of 9 th Month • 18 -20 inches long • Weighs 7 -9 pounds • Organs have developed enough to function on their own • Baby shifts to prepare for birth

Things to Avoid During Pregnancy

Dangers to the Fetus • Fetal Alcohol Syndrome (FAS)—Alcohol related birth defects that includes physical & mental problems – Low birth weight, poor coordination, mental retardation, impaired speech, stunted growth and poor attention span • Tobacco—Can affect growth, mental development and behavior – Leads to low birth weight, heart and brain abnormalities, and Sudden Infant Death Syndrome (SIDS)

• Medications & Drugs—Prescription and non-prescription should be checked with doctor first – Can cause birth defects, premature labor, or miscarriage – Baby can be born addicted to the drug • Caffeine—Some studies prove that it can cause health issues, best to avoid

Toxic Substances • • • Cat Litter Solvents Lead Mercury Insecticides

Procedures

• Pregnant women should eat a well balanced diet – they are eating for 2!!! • Take vitamins • Go to the doctor regularly for checkups

Atypical Conditions During Pregnancy • Twins – Identical – 1 egg & 1 sperm divides Fraternal – 2 separate eggs & sperm Conjoined – twins joined at birth Other Multiples

Multiples = twins, triplets, quads, quints, sextuplets, septuplets, octuplets!