411 Chapter 2

  1. Zygote
    The single cell formed from separate sperm and egg cells at conception.
  2. Ovum
    The cell released monthly from a woman's ovaries, which, if fertilized, forms the basics for the developing organism.
  3. Fallopian Tube
    The tube between the ovary and the uterus down which the ovum travels to the uterus and in which conception usually occurs.
  4. Uterus
    The female organ in which the embryo/fetus develops (popularly referred to as the womb).
  5. Sperm
    The cells produced in a man's testes that may fertilize an ovum following intercourse.
  6. Chromosomes
    The structures, arrayed in 23 pairs, within each cell in the body that contain genetic information. Each chromosome is made up of many segments called genes.
  7. Gametes
    Sperm and ova . These cells, unlike all other cells of the body, contain only 23 chromosome rather than 23 pairs.
  8. Deoxyribonucleic Acid (DNA)
    The chemical of which chromosomes are composed.
  9. Gene
    A uniquely coded segment of DNA in a chromosome that affects one or more specific body processes or developments.
  10. Homozygous
    Term describing the genetic pattern when the two genes in the pair at any given genetic locus both carry the same instructions.
  11. Heterozygous
    Term describing the genetic pattern when the two genes in the pair at any given genetic locus both carry different instructions, such as a gene for blue eyes from one parent and a gene for brown eyes from the other parent.
  12. Genotype
    The pattern of characteristics and developmental sequences mapped in the genes of any specific individual, which will be modified by individual experience into the phenotype.
  13. Phenotype
    The expression of a particular set of genetic information in a specific environmen; the observable result of the joint operation of genetic and environmental influences.
  14. Dominant/recessive Pattern of Inheritance
    The pattern of genetic transmission in which a single dominant gene influences a person's phenotype, but an individual must have two recessive genes to express a recessive trait.
  15. Polygenic Pattern of Inheritance
    Any pattern of genetic transmission in which multiple genes contribute to the outcome, such as is presumed to occur for complex traits such as intelligence or temperament.
  16. Multifactorial Pattern of Inheritance
    The pattern of genetic transmission in which both genes and environment influence the phenotype.
  17. Fraternal (dizygotic) twins
    Children carried in the same pregnancy but who develop from two separately fertilized ova. They are no more alike genetically than other pairs of siblings.
  18. Identical (monozygotic) twins
    Children carried in the same pregnancy but who develop from the same fertilized ova. They are genetic clones of each other.
  19. Germinal Stage
    The first stage of prenatal development, beginning at conception and ending at implanatation of the zygote in the uterus (approximately the first 2 weeks).
  20. Blastocyst
    Name for the mass of cells from roughly 4 to 10 days after fertilization.
  21. Embryo
    The name given to the developing organism during the period of prenatal development between about 2 weeks and 8 weeks after conception, beginning with implantation of the blastocyst in the uterine wall.
  22. Embryonic Stage
    The second stage of prenatal development, from week 2 through week 8, when the embryo's organs form.
  23. Amnion
    The sac, or bag filled with liquid in which the embryo/fetus floats during prenatal life.
  24. Chorion
    The outer layer of cells of the blastocyst during prenatal development, from which both the placenta and umbilical cord are formed.
  25. Placenta
    An organ that develops between the fetus and the wall of the uterus during gestation.
  26. Umbilical Cord
    The cord connecting the embryo/fetus to the placenta, containing two arteries and one vein.
  27. Fetus
    The name given to the developing organism from about about 8 weeks after conception until birth.
  28. Fetal Stage
    The third stage of prenatal development, from week 8 to birth, when growth and organ refinement take place.
  29. Viability
    The fetus's capacity for survival outside the womb.
  30. Neurons
    The cells in the nervous system that are responsible for tramsmission and reception of nerve impulses.
  31. Neuronal Proliferation
    The rapid development of neurons between the 10th and 18th week of gestation.
  32. Neuronal Migration
    The movement of neurons to specialized regions of the birth.
  33. Cell Body
     The part of the cell that contains the nucleus and in which all the cell's vital functions are carried out.
  34. Synapses
    Tiny spaces across which neural impulses flow from one neuron to the next.
  35. Axons
    Tall-like extensions of neurons.
  36. Dendrites
    Branchlike protrusions from the cell bodies of neurons.
  37. Glial Cells
    The "glue" that holds neurons together to give form to the structures of the nervous system.
  38. Teratogens
    Substances such as viruses and drugs or events that can cause birth defects.
  39. Down Syndrome (Trisomy 21)
    A genetic anomaly in which every cell contains three copies of chromosome 21 rather than two. Children born with this genetic pattern have characteristic physical features and usually have mental retardation.
  40. Fetal Alcohol Syndrome (FAS)
    A pattern of abnormalities, including mental retradation and minor physical anomalies, often found in children born to alcoholic mothers.
Card Set
411 Chapter 2
Prenatal Development