Chapter 8.4-8.5 Flashcards
Fertilization process
sperm and ovum unite to form a single-cell zygote with 46 chromosomes. Zygote then divides in mitosis, forming a baby. If it divides improperly, it can form twins or more!
Monozygotic Twins
Identical, one zygote splits into two separate masses of cells, forming two embryos
Dizygotic Twins
Fraternal, women’s body releases two fertilized eggs at different times forming two embryos
Bioethics
study of ethical and moral issues in biology and medicine
The 3 Stages of Prenatal Development
1) Germinal Period (0-2 weeks)
2) Embryonic Period (2-8 weeks)
3) Fetal Period (8 weeks - birth)
The Germinal Period (def and features)
- the first two weeks after fertilization where the zygote divides and moves down the uterus (protective organ) and implants in the lining
- Placenta (organ the nourishes and filters waste) and umbilical cord (connects baby to the placenta) are formed
- Cells begin to differentiate and specialize
The Embryonic Period (def and features)
- (2-8 weeks) time of major organ and structure development (eyes, lips, nose, teeth, heart) all while being an inch tall
Critical Periods
times when environmental factors can impact infant development of certain organs
Teratogen
substance that can cause a birth defect, i.e. Fetal-Alcohol-Spectrum-Disorders
Embryo
name for organism developing from 2-8 weeks
The Fetal Period
- (8 weeks - term) period categorized by tremendous growth
- age of viability where an infant could survive outside the womb ranges from around 22-26 weeks
- most children are born during the 38th-40th week
- most miscarriages happen within the first 3 months