Lecture 8 deepseek

Question 1

Prenatal Development Stages

Answer 1

1. Zygote (0-2 weeks: conception→implantation)
2. Embryo (3-8 weeks: organ formation)
3. Fetus (9w-birth: growth/finishing)

Question 2

Zygote Blastocyst Layers

Answer 2

Ectoderm (skin/nerves), Mesoderm (muscles/bones), Endoderm (digestive/respiratory)

Question 3

Mitosis vs. Meiosis

Answer 3

Mitosis: cell replication (diploid→diploid); Meiosis: gamete production (diploid→haploid, with recombination)

Question 4

Twin Types

Answer 4

Monozygotic (1 egg→identical) vs. Dizygotic (2 eggs→fraternal)

Question 5

Embryonic Development

Answer 5

Cephalocaudal (head→tail) & Proximodistal (center→outward)

Question 6

Placenta Function

Answer 6

Supplies O₂/nutrients; removes waste; filters SOME toxins (not all, e.g., alcohol)

Question 7

Fetal Reflexes (12w+)

Answer 7

Grasp, Babinski (toe spread), Sucking – same as newborn reflexes

Question 8

Fetal Sensory Experience

Answer 8

• Tactile (thumb-sucking),
• Taste (prefers sweet),
• Hearing (mom’s voice ↑heart rate),
• Sight Limited
• Smell

Question 9

Fetal Learning Evidence

Answer 9

Habituation by 30w; recognizes mom’s voice; post-birth preference for familiar smells/tastes

Question 10

Teratogens Definition

Answer 10

external environmental agents that can cause damage or death during the prenatal period

Question 11

Critical Periods

Answer 11

1st trimester most vulnerable (organogenesis); e.g., rubella at 8w → 85% birth defects

Question 12

Fetal Alcohol Spectrum Disorder FASD Symptoms

Answer 12

Microcephaly, facial malformations, CNS damage, IQ↓, hyperactivity – NO safe alcohol dose

Question 13

Thalidomide Impact

Answer 13

1950s anti-nausea drug → limb deformities, deafness, brain damage

Question 14

Rubella Consequences

Answer 14

8w exposure: 60-85% defects (blindness/deafness); 1964 epidemic linked to psychosis risk

Question 15

Support Structures

Answer 15

Amnion (cushioning fluid), 羊膜
Chorion (placenta lining), 绒毛膜, 最终会形成胎盘内
Allantois –> Umbilical Cord (3 vessels: 1 nutrient, 2 waste) 尿囊形成脐带