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Questions and Answers
What is the average volume of sperm in a normal ejaculation?
What is the average volume of sperm in a normal ejaculation?
At what stage of development is a conceptus formed?
At what stage of development is a conceptus formed?
What is the age of viability for a fetus generally accepted as capable of survival if born?
What is the age of viability for a fetus generally accepted as capable of survival if born?
Which of the following best describes the term zygote?
Which of the following best describes the term zygote?
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What is the primary role of hyaluronidase during fertilization?
What is the primary role of hyaluronidase during fertilization?
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How many chromosomes are present in a human embryo?
How many chromosomes are present in a human embryo?
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Which term describes the fetal development stage from week 8 until birth?
Which term describes the fetal development stage from week 8 until birth?
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What process occurs in the first 24 hours after fertilization?
What process occurs in the first 24 hours after fertilization?
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Which structure is responsible for oxygenating blood in the fetus?
Which structure is responsible for oxygenating blood in the fetus?
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What is the primary function of the aorta in fetal circulation?
What is the primary function of the aorta in fetal circulation?
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During which week may a fetal heartbeat be recorded with a Doppler instrument?
During which week may a fetal heartbeat be recorded with a Doppler instrument?
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What is the role of surfactant produced by alveolar cells?
What is the role of surfactant produced by alveolar cells?
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Which structure begins to divide the esophagus and trachea around the 4th week of development?
Which structure begins to divide the esophagus and trachea around the 4th week of development?
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What is the primary aspect of organogenesis in early fetal development?
What is the primary aspect of organogenesis in early fetal development?
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What is the approximate heart rate stabilized at during the 28th week of pregnancy?
What is the approximate heart rate stabilized at during the 28th week of pregnancy?
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What is an important function of the connective tissues in the fetal body?
What is an important function of the connective tissues in the fetal body?
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At what week of intrauterine life does the eye and inner ear begin to grow rapidly?
At what week of intrauterine life does the eye and inner ear begin to grow rapidly?
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What is a major risk if the intestines do not rotate 180 degrees during development?
What is a major risk if the intestines do not rotate 180 degrees during development?
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Which layer of the adrenal glands is responsible for producing cortisol?
Which layer of the adrenal glands is responsible for producing cortisol?
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When does the fetus's gastrointestinal tract start secreting enzymes essential for digestion?
When does the fetus's gastrointestinal tract start secreting enzymes essential for digestion?
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The adrenal gland's zona glomerulosa is primarily associated with which hormone's secretion?
The adrenal gland's zona glomerulosa is primarily associated with which hormone's secretion?
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At which gestational week does the meconium begin to accumulate?
At which gestational week does the meconium begin to accumulate?
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Which hormone is produced by the fetal pancreas, although it is not mature until 3 months after birth?
Which hormone is produced by the fetal pancreas, although it is not mature until 3 months after birth?
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What indicates that the ears can respond to sound by 24 weeks gestation?
What indicates that the ears can respond to sound by 24 weeks gestation?
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What is the primary function of insulin in the body?
What is the primary function of insulin in the body?
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Which enzyme is specifically associated with fat digestion?
Which enzyme is specifically associated with fat digestion?
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What condition is characterized by excessive breakdown products from destroyed RBCs in newborns?
What condition is characterized by excessive breakdown products from destroyed RBCs in newborns?
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What is lanugo and its role during fetal development?
What is lanugo and its role during fetal development?
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At what stage of pregnancy can a fetus first be observed moving in ultrasonography?
At what stage of pregnancy can a fetus first be observed moving in ultrasonography?
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Which immunoglobulin crosses the placenta and provides temporary passive immunity to the fetus?
Which immunoglobulin crosses the placenta and provides temporary passive immunity to the fetus?
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When does the ossification of cartilage into bones begin during fetal development?
When does the ossification of cartilage into bones begin during fetal development?
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When can the sex of a fetus be determined with a high degree of certainty?
When can the sex of a fetus be determined with a high degree of certainty?
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What significant developmental milestone occurs by the end of the 24th gestational week?
What significant developmental milestone occurs by the end of the 24th gestational week?
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Which reflex is actively demonstrated in a newborn at birth?
Which reflex is actively demonstrated in a newborn at birth?
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What happens to the eyelids around the 12th week of gestation?
What happens to the eyelids around the 12th week of gestation?
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What cue indicates that the fetus is responding to sound?
What cue indicates that the fetus is responding to sound?
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What is a potential consequence if the testes do not descend into the scrotal sac?
What is a potential consequence if the testes do not descend into the scrotal sac?
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Which of the following is a key change that occurs by the end of the 36th gestational week?
Which of the following is a key change that occurs by the end of the 36th gestational week?
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What happens to lanugo by the end of the 28th gestational week?
What happens to lanugo by the end of the 28th gestational week?
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What indicates that a newborn may have Down syndrome based on the sole of the foot?
What indicates that a newborn may have Down syndrome based on the sole of the foot?
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Study Notes
Stages of Fetal Development
- Pre-embryonic period lasts the first 2 weeks post-fertilization.
- Embryonic period spans from weeks 3 to 8.
- Fetal period extends from week 8 until birth.
Fetal Growth Terms
- Zygote: From fertilization until implantation in the uterus.
- Embryo: From implantation to 5-8 weeks, consists of 46 chromosomes (22 pairs of autosomes plus 1 pair of sex chromosomes).
- Fetus: Development from 5-8 weeks until term.
- Conceptus: Refers to the developing embryo and placental structures throughout pregnancy.
- Age of viability: Approximately 24 weeks gestation or weighing over 500 grams.
Fertilization Journey
- Journey of the zygote includes movement from the Fallopian tube to the uterus over 3-4 days, with mitotic division occurring during implantation.
- A blastocyst forms, consisting of the inner embryoblast (embryo) and outer trophoblast (placenta).
Trimester Divisions
- 1st trimester: 0-12 weeks, significant developmental processes occur.
- 2nd trimester: 13-24 weeks, continued development and maturation.
- 3rd trimester: 24-40 weeks, preparing for birth.
Major Organ Development
- Cardiovascular System: First functional system; heart forms early (16th day) and beats by the 24th day.
- Respiratory System: Respiratory passages develop by the 3rd week, with lungs beginning to form at 4 weeks.
- Digestive System: Develops as a solid structure, and significant changes occur after 16 weeks.
Hormonal Functions and Endocrine System
- Adrenal glands regulate metabolism and immune response, producing cortisol, aldosterone, and androgens.
- Fetal pancreas develops insulin and glucagon to manage blood sugar levels.
Immune System Development
- Maternal immunoglobulin IgG antibodies cross the placenta as early as 20 weeks, providing passive immunity to the fetus.
Musculoskeletal and Integumentary Systems
- Initial cartilage formation occurs in the first 2 weeks; ossification begins around week 12.
- Skin initially thin and translucent, covered by lanugo and vernix caseosa for protection and insulation.
Fetal Responses and Development Milestones
- Fetus begins to move by week 11 (quickening); sound responses develop by week 24.
- Essential nutrient stores, such as iron and glycogen, increase in the later weeks of pregnancy.
Key Developmental Weeks
- By the end of the 24th week: fetus demonstrates viability, responds to light and sound, and performs gilt reflexes.
- By the end of the 28th week: maternal antibodies provide immunity, and lanugo decreases.
- By the end of the 36th week: body stores critical nutrients, eye responses to light react, and significant weight gain occurs.
Final Development Stages
- By the end of the 40th week: fetal hemoglobin starts converting to adult hemoglobin; the fetus is actively moving.
- If testes do not descend, it may result in cryptorchidism, compromising fertility and health.
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Description
Explore the crucial stages of fetal development, from pre-embryonic to fetal periods. Learn about key terms such as zygote, embryo, fetus, and conceptus, along with the journey of fertilization. This quiz will test your knowledge of prenatal growth and trimester divisions.
