Ch 1
✅ 1. Process of Fertilization, Implantation, and Cell Differentiation
🔹 Fertilization
Occurs when a sperm cell penetrates a mature egg (ovum) in the fallopian
tube.
Forms a single cell called a zygote, containing genetic material from both
parents (46 chromosomes total).
🔹 Implantation
The zygote divides multiple times to become a morula, then a blastocyst.
Around day 6–10 after fertilization, the blastocyst implants into the
uterine lining (endometrium).
The outer layer of the blastocyst, the trophoblast, develops into the
placenta.
🔹 Cell Differentiation
After implantation, cells begin to specialize into three primary layers:
o Ectoderm (skin, brain, nerves)
o Mesoderm (muscles, bones, blood)
o Endoderm (digestive and respiratory systems)
This specialization allows the formation of all body systems.
✅ 2. Normal Fetal Development (Conception to Birth)
🍼 Preembryonic Stage (Weeks 1–2)
Fertilization → zygote → morula → blastocyst → implantation.
🍼 Embryonic Stage (Weeks 3–8)
Major organs begin to develop.
Heart starts beating by week 4.
Neural tube forms → brain and spinal cord.
Limbs and facial features start to appear.
🍼 Fetal Stage (Weeks 9–Birth)
Weeks 9–12: External genitalia visible; kidneys start functioning.
Weeks 13–24: Lanugo (fine hair) and vernix form; mother may feel fetal
movement (~20 weeks).
Weeks 25–28: Lungs produce surfactant; eyes open.
Weeks 29–40: Rapid weight gain; organs mature; fetus prepares for life
outside womb.
✅ 3. Functions of the Placenta, Umbilical Cord, and Amniotic Fluid
1
,🔹 Placenta
Provides oxygen and nutrients to the fetus.
Removes waste products.
Produces hormones (e.g., hCG, estrogen, progesterone).
Acts as a barrier (partially) to some harmful substances.
🔹 Umbilical Cord
Contains two arteries and one vein.
Connects fetus to placenta.
Delivers nutrients and oxygen to the fetus, removes CO₂ and waste.
🔹 Amniotic Fluid
Cushions and protects the fetus.
Maintains temperature and allows movement for muscle and bone development.
Prevents compression of the umbilical cord.
Assists in lung development (as fetus "breathes" in fluid).
✅ 4. Ethical and Legal Issues in Genetic Testing
🔍 Examples Include:
Informed consent: Patients must fully understand risks, benefits, and options.
Privacy and confidentiality: Who has access to genetic information?
Discrimination: Potential bias in insurance or employment (protected by GINA – Genetic
Information Nondiscrimination Act).
Prenatal decisions: Ethical concerns with selective abortion or designer babies.
Family impact: One person’s test may reveal information about relatives (e.g., risk of BRCA
mutations).
✅ 5. Inheritance Patterns (Traditional & Nontraditional)
🔹 Traditional (Mendelian) Patterns
Autosomal Dominant: Only one copy of the gene is needed (e.g., Huntington's disease).
Autosomal Recessive: Two copies are needed (e.g., cystic fibrosis).
X-linked Recessive: Usually affects males (e.g., hemophilia).
🔹 Nontraditional Patterns
Mitochondrial Inheritance: Passed only from mother to child (e.g., mitochondrial myopathy).
Multifactorial Inheritance: Caused by genes + environment (e.g., diabetes, heart disease).
Genomic imprinting: Gene expression depends on whether it’s inherited from the mother or
father.
✅ 6. Role of the Nurse in Genetic Counseling and Related Activities
🩺 Nursing Responsibilities:
Assessment: Gather thorough family and medical history.
Education: Explain genetic risks, inheritance patterns, and testing options in clear terms.
Support: Provide emotional support during decision-making and after test results.
Referral: Refer to a certified genetic counselor or specialist as appropriate.
Advocacy: Ensure informed consent, patient autonomy, and privacy.
2
, Collaboration: Work with interdisciplinary teams (OB, oncology, pediatrics, etc.) in
planning care.
Summary of Preembryonic Development
Fertilization takes place in the ampulla of the fallopian tube.
Union of sperm and ovum forms a zygote (46 chromosomes).
Cleavage cell division continues to form a morula (mass of 16 cells).
The inner cell mass is called a blastocyst, which forms the embryo and
amnion.
The outer cell mass is called a trophoblast, which forms the placenta and
chorion.
Implantation occurs 7 to 10 days after conception in the endometrium.
Placenta
it brings oxygen and nutrients to the growing fetus and moves waste
away from it.
protects the fetus from an immune attack by the pregnant person’s
body and induces them to eat more, thereby bringing more food to the
placenta.
Near the time of delivery, it produces hormones that ready fetal organs
for life outside the uterus
Using diffusion, the placenta acts as a pass-through between the
pregnant person and fetus, not a barrier.
TEROTOGENS
Ionizing radiation—leads to abnormal brain development, mental
impairment, and leukemia
Organic mercury—leads to damage of the neural system, mental
impairment, behavioral and cognitive problems, and blindness
Lead exposure—can cause spontaneous abortion, delayed fetal
development, increased risk of fetal death, or abnormal mental or physical
development
Toxoplasma—leads to spontaneous abortion or stillbirth, underdeveloped
fetal brain, blindness, and seizures
Syphilis bacteria—can cause fetal death, spontaneous abortion, liver and
spleen enlargement, and congenital syphilis
3
, Rubella virus—leads to abnormal brain development
Cytomegalovirus—leads to underdevelopment of the fetal brain, blindness,
deafness, jaundice, and liver and spleen dysfunction
Varicella zoster—leads to underdeveloped limbs and brain or eye
malformations
Herpes virus—causes fetal death, microcephaly, herpetic pneumonia, and
meningoencephalitis
Maternal conditions—obesity, diabetes, hypothyroidism, hyperthyroidism,
and phenylketonuria (PKU)
Medications—antiepileptic drugs (cognitive defects, structural
malformations); vitamin A in large doses (thymic and cardiac anomalies);
anticoagulants (fetal skeletal abnormalities); and certain antimicrobials such
as tetracycline (liver necrosis, bone and teeth defects
FETAL CIRCULATION
Fetal circulation functions to carry highly oxygenated blood to vital areas
(e.g., heart, brain) while first shunting it away from less important ones (e.g.,
lungs, liver). The placenta essentially takes over the functions of the lungs
and liver during fetal life. As a result, large volumes of oxygenated blood are
not needed.
Human Genome Project
started in 1990 by the Department of Energy and the National Institutes of Health
(NIH) and was completed in May 2003.
The goals of the HGP were to map, sequence, and determine the function of the
human genome, which led to advances in the field of genetics and genetic testing
A person’s genetic profile can help guide decisions made regarding prevention,
diagnosing, and treating disease.
Genetic Testing, Diagnosis, and Therapy
Gene therapy is a technique to prevent, treat, or cure a medical condition. It works
by adding new copies of a broken gene, replacing a defective or missing gene with a
healthy version of that gene.
It can be used to replace or repair defective or missing genes with normal ones
Mendelian or Monogenic Laws of Inheritance
4
✅ 1. Process of Fertilization, Implantation, and Cell Differentiation
🔹 Fertilization
Occurs when a sperm cell penetrates a mature egg (ovum) in the fallopian
tube.
Forms a single cell called a zygote, containing genetic material from both
parents (46 chromosomes total).
🔹 Implantation
The zygote divides multiple times to become a morula, then a blastocyst.
Around day 6–10 after fertilization, the blastocyst implants into the
uterine lining (endometrium).
The outer layer of the blastocyst, the trophoblast, develops into the
placenta.
🔹 Cell Differentiation
After implantation, cells begin to specialize into three primary layers:
o Ectoderm (skin, brain, nerves)
o Mesoderm (muscles, bones, blood)
o Endoderm (digestive and respiratory systems)
This specialization allows the formation of all body systems.
✅ 2. Normal Fetal Development (Conception to Birth)
🍼 Preembryonic Stage (Weeks 1–2)
Fertilization → zygote → morula → blastocyst → implantation.
🍼 Embryonic Stage (Weeks 3–8)
Major organs begin to develop.
Heart starts beating by week 4.
Neural tube forms → brain and spinal cord.
Limbs and facial features start to appear.
🍼 Fetal Stage (Weeks 9–Birth)
Weeks 9–12: External genitalia visible; kidneys start functioning.
Weeks 13–24: Lanugo (fine hair) and vernix form; mother may feel fetal
movement (~20 weeks).
Weeks 25–28: Lungs produce surfactant; eyes open.
Weeks 29–40: Rapid weight gain; organs mature; fetus prepares for life
outside womb.
✅ 3. Functions of the Placenta, Umbilical Cord, and Amniotic Fluid
1
,🔹 Placenta
Provides oxygen and nutrients to the fetus.
Removes waste products.
Produces hormones (e.g., hCG, estrogen, progesterone).
Acts as a barrier (partially) to some harmful substances.
🔹 Umbilical Cord
Contains two arteries and one vein.
Connects fetus to placenta.
Delivers nutrients and oxygen to the fetus, removes CO₂ and waste.
🔹 Amniotic Fluid
Cushions and protects the fetus.
Maintains temperature and allows movement for muscle and bone development.
Prevents compression of the umbilical cord.
Assists in lung development (as fetus "breathes" in fluid).
✅ 4. Ethical and Legal Issues in Genetic Testing
🔍 Examples Include:
Informed consent: Patients must fully understand risks, benefits, and options.
Privacy and confidentiality: Who has access to genetic information?
Discrimination: Potential bias in insurance or employment (protected by GINA – Genetic
Information Nondiscrimination Act).
Prenatal decisions: Ethical concerns with selective abortion or designer babies.
Family impact: One person’s test may reveal information about relatives (e.g., risk of BRCA
mutations).
✅ 5. Inheritance Patterns (Traditional & Nontraditional)
🔹 Traditional (Mendelian) Patterns
Autosomal Dominant: Only one copy of the gene is needed (e.g., Huntington's disease).
Autosomal Recessive: Two copies are needed (e.g., cystic fibrosis).
X-linked Recessive: Usually affects males (e.g., hemophilia).
🔹 Nontraditional Patterns
Mitochondrial Inheritance: Passed only from mother to child (e.g., mitochondrial myopathy).
Multifactorial Inheritance: Caused by genes + environment (e.g., diabetes, heart disease).
Genomic imprinting: Gene expression depends on whether it’s inherited from the mother or
father.
✅ 6. Role of the Nurse in Genetic Counseling and Related Activities
🩺 Nursing Responsibilities:
Assessment: Gather thorough family and medical history.
Education: Explain genetic risks, inheritance patterns, and testing options in clear terms.
Support: Provide emotional support during decision-making and after test results.
Referral: Refer to a certified genetic counselor or specialist as appropriate.
Advocacy: Ensure informed consent, patient autonomy, and privacy.
2
, Collaboration: Work with interdisciplinary teams (OB, oncology, pediatrics, etc.) in
planning care.
Summary of Preembryonic Development
Fertilization takes place in the ampulla of the fallopian tube.
Union of sperm and ovum forms a zygote (46 chromosomes).
Cleavage cell division continues to form a morula (mass of 16 cells).
The inner cell mass is called a blastocyst, which forms the embryo and
amnion.
The outer cell mass is called a trophoblast, which forms the placenta and
chorion.
Implantation occurs 7 to 10 days after conception in the endometrium.
Placenta
it brings oxygen and nutrients to the growing fetus and moves waste
away from it.
protects the fetus from an immune attack by the pregnant person’s
body and induces them to eat more, thereby bringing more food to the
placenta.
Near the time of delivery, it produces hormones that ready fetal organs
for life outside the uterus
Using diffusion, the placenta acts as a pass-through between the
pregnant person and fetus, not a barrier.
TEROTOGENS
Ionizing radiation—leads to abnormal brain development, mental
impairment, and leukemia
Organic mercury—leads to damage of the neural system, mental
impairment, behavioral and cognitive problems, and blindness
Lead exposure—can cause spontaneous abortion, delayed fetal
development, increased risk of fetal death, or abnormal mental or physical
development
Toxoplasma—leads to spontaneous abortion or stillbirth, underdeveloped
fetal brain, blindness, and seizures
Syphilis bacteria—can cause fetal death, spontaneous abortion, liver and
spleen enlargement, and congenital syphilis
3
, Rubella virus—leads to abnormal brain development
Cytomegalovirus—leads to underdevelopment of the fetal brain, blindness,
deafness, jaundice, and liver and spleen dysfunction
Varicella zoster—leads to underdeveloped limbs and brain or eye
malformations
Herpes virus—causes fetal death, microcephaly, herpetic pneumonia, and
meningoencephalitis
Maternal conditions—obesity, diabetes, hypothyroidism, hyperthyroidism,
and phenylketonuria (PKU)
Medications—antiepileptic drugs (cognitive defects, structural
malformations); vitamin A in large doses (thymic and cardiac anomalies);
anticoagulants (fetal skeletal abnormalities); and certain antimicrobials such
as tetracycline (liver necrosis, bone and teeth defects
FETAL CIRCULATION
Fetal circulation functions to carry highly oxygenated blood to vital areas
(e.g., heart, brain) while first shunting it away from less important ones (e.g.,
lungs, liver). The placenta essentially takes over the functions of the lungs
and liver during fetal life. As a result, large volumes of oxygenated blood are
not needed.
Human Genome Project
started in 1990 by the Department of Energy and the National Institutes of Health
(NIH) and was completed in May 2003.
The goals of the HGP were to map, sequence, and determine the function of the
human genome, which led to advances in the field of genetics and genetic testing
A person’s genetic profile can help guide decisions made regarding prevention,
diagnosing, and treating disease.
Genetic Testing, Diagnosis, and Therapy
Gene therapy is a technique to prevent, treat, or cure a medical condition. It works
by adding new copies of a broken gene, replacing a defective or missing gene with a
healthy version of that gene.
It can be used to replace or repair defective or missing genes with normal ones
Mendelian or Monogenic Laws of Inheritance
4
