NUR4467 M1 PT2, NUR 4467 M1 Exam
Study Guide.
Genetics - answerrefers to the study of a particular gene
Genomics - answerrefers to the study of the entire genome
Genes - answerbasic physical units of inheritance that are passed from parents to offspring
and contain the information needed to sp...
Name 5 sex-linked inherited disorders - answer✔- Hemophilia (blood does not clot properly; x-
linked recessive)
- Turner's syndrome
- red-green color blindness (x linked recessive)
- Duchenne Muscular dystrophy (x linked recessive)
- Fragile X (x linked dominant)
Autosomal Dominant - answer✔- only requires ONE affected gene for a disease to express
itself
- can appear in either sex, and do not skip generations
- With one affected parent, offspring will have a 50% chance of being affected and a 50% chance
of being unaffected
X-linked Dominant - answer✔- only one copy of the gene is needed to express itself, ie to
cause a disease
- When the FATHER has the disease. ALL 100%)of his daughters will be affected, because they
will inherit his ONLY x chromosome, and hence the affected gene. None of his sons will be
affected.
- When the MOTHER is affected, 50% of her daughters and sons will have a chance of being
affected.
- When both are affected with one copy, Male offspring have a 50% chance of being affected,
Girls a 100% chance. Overall there is a 75% chance of having an affected child and 25% chance
unaffected male
**remember, a boy will always get his X from mom, because he's got the Y from dad! And a girl
will always get one X from mom and one X from dad.
X-linked Recessive - answer✔- If a male inherits the affected copy, even though it is a
recessive gene, they will be affected because they only inherit one x chromosome.
- If the mother has one copy of the gene, male offspring have a 50% chance of inheriting it and
being affected, and a 50% chance of being unaffected.
- Girls have a 50% chance of being a carrier or being unaffected.
What are high-risk factors for genetic disorders? - answer✔- Advanced maternal age (>35 y/o)
- Prior history in previous pregnancies
- One or both parents with a disorder
- Family history of disorder
Oogenesis - answer✔the process of egg (ovum) formation
Spermatogenesis - answer✔production of sperm; cells that undergo meiosis in the male are
called spermatocytes
Conception - answer✔the union of a single egg and sperm, marks the beginning of a pregnancy
This sequential process includes gamete (egg and sperm) formation, ovulation (release of the
egg), union of the gametes (which results in an embryo), and implantation in the uterus.
What are the 3 primary germ layers? - answer✔ectoderm, mesoderm, endoderm
When does the embryonic disk differentiate into the 3 primary germ layers? - answer✔3rd
week after conception
What days are considered an embryo? - answer✔From Day 15 to 8 weeks
What days are considered a fetus? - answer✔8th week until term
What is the chorion? - answer✔- is the outer membrane that surrounds the amnion, the embryo
and other membranes and entities in the womb.
- becomes covering of the fetal side of the placenta and contains major umbilical blood vessels
that branch out over the placenta
-Formed by two layers; trophoblast as the outer layer and mesoderm as the inner layer.
What is the amnion? - answer✔is a thin but tough sac of membrane that covers an embryo.
-Main purpose is to protect the embryo during the months of pregnancy. It helps reduce the risk
of injuries to the unborn embryo and its development in the womb.
- becomes the amniotic sac which fills with amniotic fluid
How much amniotic fluid is released at term?? - answer✔Between 700-1000 mL of clear fluid
What is the yolk sac? - answer✔- aids in transferring maternal nutrients and oxygen, which
have diffused through the chorion, to the embryo
- manufactures blood cells and plasma during the second and third weeks while uteroplacental
circulation is being established and is forming primitive blood cells until hematopoietic activity
begins.
- 4th week = folding in of the embryo during the fourth week results in incorporation of part of
the yolk sac into the embryo's body as the primitive digestive system
- Primordial germ cells arise in the yolk sac and move into the embryo. The shrinking remains of
the yolk sac degenerate
- By the fifth or sixth week, the remnant has separated from the embryo.
any part of the yolk sac separates from fetus and is expelled when baby is born
What is the umbilical cord? What does the artery carry? The vein? - answer✔- It is the conduit
connecting mother to infant via the placenta; contains two arteries and one vein.
- arteries = carry blood from the embryo to the chorionic villi
- vein returns blood to the embryo
How wide and long is the umbilical cord at term? - answer✔- 2 cm in width, and 30-90 cm in
length (avg = 55 cm)
What is the placenta? - answer✔- an organ that develops in your uterus during pregnancy. This
structure provides oxygen and nutrients to your growing baby and removes waste products from
your baby's blood. The placenta attaches to the wall of your uterus, and your baby's umbilical
cord arises from it.
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