Objective 4 What physical traits did I inherit?

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Objective 4What physical traits did I inherit?
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Physical TraitsA. Heredity and Environment

• Heredity-the passing of certain inherited
  characteristics from one generation to the next.
• Chromosomes-threadlike particles in the nucleus
  of a cell which carry hereditary characteristics.
  (46 chromosomes)
• Genes-the parts of the chromosomes that determine
  all inherited characteristics.

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B. Recessive and dominant genes

• Recessive-gene which can only determine a
  particular trait when paired with a similar gene.
• Dominant-stronger gene, predicts outcome of the
  trait.

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C. Sex determination

• Male-carries x or y chromosomes in the sperm.
• Female-carries only x chromosomes.
• Boy x y
• Girl x x
• Fraternal twins-when two eggs are released at the
  same time and fertilized by different sperm.
• Identical twins-one egg is released and splits
  into and fertilized by one sperm.

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Objective 4.02

• Stages of prenatal development

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A. Terms

• 1. Ovum-female cell or egg is released once a
  month, moves through the fallopian tubes to the
  uterus or womb. (2-3 days)
• 2. Conception-egg meets with sperm and is
  fertilized in the fallopian tubes.

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• Zygote/implantation-fertilized egg travels to
  the uterus and attaches itself to the thickened
  lining of the uterus and begins to grow.
• PERIOD OF THE OVUM (OVULATION, CONCEPTION,
  ZYGOTE-LASTS TWO WEEKS) FIRST STAGE
• Embryo-increasing cluster of cells-
• multiply. SECOND STAGE-LASTS SIX WEEKS.
• Major organs begin to develop. By the end of
  this stage the connecting tissue between the
  embryo and the uterus has developed into the
  placenta. Nourishment and oxygen from the
  mother's blood stream are carried from the
  placenta to the developing baby through the
  umbilical cord. Amniotic Fluid-surrounds the
  embryo and acts as a cushion to protect it even
  through minor bumps or falls of the mother.

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Fetus-3RD STAGE (17TH OR 18TH WEEK OR 4-5 MONTHS),

• unborn baby has
• 1-hair appears, 2-movement (sucking thumb,
  swallow, hiccup, move around) MOTHER FEELS
  SLIGHT FETAL MOVEMENTS.
• 3-Weight gain for mother 18-20 lbs.

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• First trimester-3 months (first three of nine
  months). All organs are formed and heartbeat can
• be heard.
• Second trimester-(2nd set of three months, months
  4,5, 6 of nine months) The fetus becomes more
  active and hair, eyelashes, and eyebrows appear.
  
• Third trimester-(last 3 months- 7,8 9) During
  eighth month weight gain of fetus increases
  rapidly while fetal movement decreases.

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Objective 4.03

• Birth Defects
• Birth defects-abnormality that affects the
  structure or function of the body.
• Some are inherited from one or both parents.
  Others are caused by controllable factors in the
  environment.

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A. Types

• Genetic-defective genes that match up with
  conception.
• Environmental-whether the mother's diet is
  nutritional, any diseases or infections that
  strike the mother during pregnancy, or any
  harmful substances such as alcohol, tobacco
  smoke, and drugs, exposure to outside hazards
  such as radiation.

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• Cystic Fibrosis-functional defect involving
  respiratory and digestive systems. Many die
  before adulthood. (Hereditary-Caucasian)
• Down's syndrome-mental retardation, delayed
  development, heart defects. Chromosomal error.
  (Extra chromosome 21)
• Fetal Alcohol Syndrome (FAS)-alcohol taken by
  mother while baby is in the womb, interferes with
  the tissue growth and development. The brain is
  most easily injured. Most all babies are
  mentally retarded.

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• Sickle-cell anemia-malformed red blood cells
  interfere with the supply of oxygen to all parts
  of the body. Symptoms include tiredness, lack of
  appetite, and pain. Can lead to early death.
  (Hereditary in African-Americans)
• Tay-Sachs Disease-lack of a specific chemical in
  the blood, resulting in the inability to
  metabolize fats. Leads to severe brain damage
  and death by age 2 or 3. (Hereditary-Jewish)

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B. Prevention

• Genetic counseling-service combines a knowledge
  of heredity and birth defects with lab tests.
• Prenatal care- prenatal tests and care before and
  after baby is born.

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Prenatal tests- any women 35 or older is a
high-risk pregnancy. Prenatal tests detect birth
defects.

• Ultrasound-uses sound waves to make a video image
  of the unborn child. (Low-risk to baby or
  mother)
• Amniocentesis-special needle in used to withdraw
  a small amount of amniotic fluid surrounding the
  baby. The fluid is taken to lab to inspect for
  defects. (risks-miscarriage)
• Chorionic villi sampling- (villi are fingers of
  tissue protruding from the chorion- the membrane
  encasing the fetus). Villi is used for analysis.
  (risks-low of miscarrriage)