Transcript Objective 4 What physical traits did I inherit?

Objective 4
What physical traits did I
inherit?
Physical Traits
A. Heredity and Environment
• Heredity-the passing of certain inherited
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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.
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.
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.
Objective 4.02
Stages of prenatal
development
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.
• 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 cellsmultiply. 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.
Fetus-3RD STAGE (17TH OR
18TH WEEK OR 4-5 MONTHS),
• unborn baby has:
1-hair appears, 2movement (sucking
thumb, swallow,
hiccup, move around)
MOTHER FEELS
SLIGHT FETAL
MOVEMENTS.
3-Weight gain for
mother 18-20 lbs.
• First trimester-3 months (first
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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 months7,8 &9) During eighth month
weight gain of fetus increases
rapidly while fetal movement
decreases.
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.
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.
• 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.
• 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 AfricanAmericans)
• 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. (HereditaryJewish)
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.
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
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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)