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Questions and Answers
What is the inner group of cells in a blastocyst called?
What percentage of blastocysts typically do not implant in the uterine wall?
During which period does the zygote become known as an embryo?
What process is primarily responsible for the division of cells during the early development of an organism?
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What major physical traits are present in the early embryonic period?
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What structure forms during the embryonic period to provide nourishment to the developing embryo?
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Which type of development refers to growth from the head to the tail?
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Which developmental stage follows the embryonic period?
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At the end of the embryonic period, what approximate size and weight does the embryo reach?
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What is one major reason fewer than half of all zygotes survive beyond the first two weeks?
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What capability does the embryo exhibit by the end of the embryonic stage?
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During prenatal development, which structures develop first in relation to their proximity to the torso?
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What is the age of viability for a fetus?
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Which system continues to develop during the fetal period?
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Why are potential mothers often unaware of risks during the embryonic period?
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Which reflexes develop during the 5th month of fetal development?
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What is the duration of the germinal period in prenatal development?
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Which stage follows the germinal period in prenatal development?
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What is a zygote?
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What prevents additional sperm from entering the egg after fertilization?
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During which process does the fertilized egg travel to the uterus?
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What is the primary event that occurs during the germinal period?
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Where does fertilization typically take place?
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What becomes of the sperm's tail after it enters the egg?
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What factors can influence the impact of teratogens on a developing fetus?
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Which of the following substances is noted as a prominent teratogen?
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How does the exposure to multiple teratogens affect fetal development compared to exposure to a single teratogen?
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What is one of the leading preventable causes of intellectual disabilities in children?
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Which chromosome is associated with a higher likelihood of damage due to teratogen exposure?
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What physical features are commonly associated with Fetal Alcohol Syndrome (FAS)?
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What critical period around conception is mentioned for the development of arms and ears?
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What is the umbrella term for the range of effects that can occur due to alcohol consumption during pregnancy?
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What are some cognitive effects associated with children affected by fetal alcohol exposure?
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What is a significant risk factor for having a baby with Fetal Alcohol Spectrum Disorder (FASD)?
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Which of the following is NOT a facial feature typically associated with Fetal Alcohol Spectrum Disorder?
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What percentage of pregnant women reported smoking during pregnancy in 2016?
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What long-term problems may persist into adulthood for individuals affected by prenatal alcohol exposure?
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Which of the following statements about smoking among pregnant women is accurate?
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Which characteristic is included in the facial features of Fetal Alcohol Spectrum Disorders?
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What common behavior during pregnancy has been reported by 23% of women before they became pregnant?
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Study Notes
Prenatal Development Periods
- Prenatal development consists of three periods: the germinal, embryonic, and fetal periods.
- The germinal period lasts from conception to implantation of the fertilized egg in the uterine lining and typically lasts around 14 days.
- During the germinal period, cell division occurs through mitosis, leading to the formation of a blastocyst, containing the inner cell mass that will become the embryo and outer cells that form the support system.
- Approximately 50-75% of blastocysts do not implant, and fewer than half of all zygotes survive beyond the first two weeks.
- The embryonic period starts in the third week, with the blastocyst implanted in the uterine wall.
- Growth during prenatal development occurs in two directions:
- Cephalocaudal development (head to tail)
- Proximodistal development (midline outward)
- The embryonic period is crucial for the formation of major body structures and is the stage when the organism is most vulnerable to harm.
- The fetal period, from the ninth week until birth, sees the continued development of major structures and the appearance of external genitalia, hair, nails, teeth, and functional excretory and digestive systems.
Prenatal Brain Development
- The brain rapidly develops during the fetal period, with connections between neurons forming and increasing complexity.
- The brain development process continues after birth, with a significant number of neurons and connections forming during the first few years of life.
Teratogens
- Teratogens are environmental agents that can harm the developing fetus.
- Factors influencing teratogen effects include:
- Amount of exposure: Certain teratogens may be harmless unless reaching a critical level.
- Number of teratogens: Multiple teratogenic exposure can lead to more severe problems.
- Genetics: Genetic makeup plays a role in the impact of teratogens, impacting both the fetus and the mother.
- Sex of the fetus: Males are more likely to suffer damage from teratogens.
Common Teratogens
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Alcohol: Leads to fetal alcohol spectrum disorders (FASD), including fetal alcohol syndrome (FAS), characterized by facial abnormalities, developmental delays, and cognitive impairments.
- FAS is the leading preventable cause of intellectual disabilities in children in the US.
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Tobacco: Increases the risk of:
- Premature birth
- Low birth weight
- Sudden infant death syndrome (SIDS)
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Drugs:
- Illegal drugs: Many drugs, such as cocaine and heroin, can lead to severe and lifelong health problems, including neurological impairments and addiction.
- Prescription drugs: Some prescription medications have teratogenic effects and should be carefully monitored during pregnancy.
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Infectious Agents:
- Rubella: Can cause deafness, blindness, and intellectual disabilities.
- HIV/AIDS: Can be transmitted to the fetus during pregnancy, labor, or breastfeeding, leading to lifelong health issues.
- Cytomegalovirus: Can cause hearing loss, cerebral palsy, and developmental delays.
- Toxoplasmosis: Can cause blindness, seizures, and mental retardation.
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Environmental Factors:
- Radiation: Can cause mental retardation and physical deformities.
- Mercury: Can cause neurological damage and developmental delays.
- Lead: Can cause learning disabilities, behavioral problems, and developmental delays.
Maternal & Paternal Factors Affecting the Fetus
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Maternal Factors:
- Age: Maternal age (both very young and older mothers) can increase the risk of complications during pregnancy.
- Nutrition: Proper nutrition is crucial for healthy fetal development, with malnutrition increasing the risk of birth defects and low birth weight.
- Stress: Chronic stress can negatively impact the fetus, potentially affecting cognitive development and behavior.
- Physical Health: Certain maternal health conditions, such as diabetes and high blood pressure, can increase the risk of complications during pregnancy.
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Paternal Factors:
- Age: Older fathers may increase the risk of certain genetic conditions and developmental problems.
- Exposure to Teratogens: Fathers' exposure to teratogens can also impact fetal health.
Prenatal Assessment Types
- Ultrasound: A non-invasive imaging technique using sound waves to visualize the fetus and assess its development.
- Amniocentesis: A procedure that involves extracting amniotic fluid containing fetal cells for genetic testing.
- Chorionic Villus Sampling: A procedure that collects tissue from the placenta to test for genetic disorders.
Complications of Pregnancy
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Minor Complications:
- Nausea and vomiting: Common in early pregnancy, usually resolving on its own.
- Back pain: Frequent as the uterus grows and puts pressure on the spine.
- Leg cramps: Can occur due to increased blood volume and pressure.
- Hemorrhoids: Enlarged veins in the rectum, often caused by increased pressure from the growing fetus.
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Major Complications:
- Premature birth: Delivery before 37 weeks of gestation, increasing the risk of health problems for the baby.
- Preeclampsia: A condition characterized by high blood pressure and protein in the urine, posing significant risks for both mother and baby.
- Gestational diabetes: A form of diabetes that develops during pregnancy, increasing the risk of complications for both mother and fetus.
- Placental abruption: When the placenta separates from the uterine wall before birth, causing severe bleeding and potential fetal distress.
- Placenta previa: A condition in which the placenta covers the cervix, potentially blocking the birth canal.
- Other potential complications include:
- Fetal growth restriction: The fetus is smaller than expected for its gestational age.
- Stillbirth: The death of a fetus after 20 weeks of gestation.
- Ectopic pregnancy: The fertilized egg implants outside the uterus, often in the fallopian tube.
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Description
Test your knowledge on the three key periods of prenatal development: germinal, embryonic, and fetal. This quiz covers important concepts including the process of implantation, growth directions, and critical stages of development. Challenge yourself and learn more about this fascinating topic!
