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Human Embryonic Development
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Human Embryonic Development
Human Embryonic Development
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1
Question
What defines the prenatal period?
Answer
Time during pregnancy before birth
2
Question
How is gestational age measured?
Answer
From mother's last menstrual cycle in weeks and days
3
Question
What is fetal age?
Answer
Time elapsed since conception
4
Question
What is a teratogen?
Answer
Any exposure causing fetal harm
5
Question
What marks the postnatal period?
Answer
Time immediately after birth
6
Question
What spans the embryonic period?
Answer
Weeks 1 through 8 after fertilization
7
Question
When does the fetal period begin and end?
Answer
Weeks 9 through 37 after fertilization
8
Question
What is a zygote?
Answer
Single cell formed by egg and sperm fertilization containing all genetic information
9
Question
What is the primitive streak?
Answer
Structure on dorsal surface of embryonic disk early in development
10
Question
What forms the endoderm?
Answer
Inner cell layer of developing embryo
11
Question
What is the ectoderm?
Answer
Outer cell layer of developing embryo
12
Question
What constitutes the mesoderm?
Answer
Middle cell layer of developing embryo
13
Question
What role does the primitive node play?
Answer
Aggregate of cells at primitive streak tip orchestrating neural development
14
Question
What is the neural plate?
Answer
Thickening of ectoderm forming neural tube basis for nervous system
15
Question
What is the notochord?
Answer
Structure from primitive streak providing directional guidance to development
16
Question
What are mesenchymal cells?
Answer
Primordial embryonic cells giving rise to epidermis, blood, and bone
17
Question
What are neural crest cells?
Answer
Primordial cells from embryonic ectoderm
18
Question
What is the pharyngeal arch system?
Answer
Arches from neural crest migration forming head and neck structures basis
19
Question
What is myogenic mesoderm?
Answer
Mesoderm developing into muscle
20
Question
What do angioblasts form?
Answer
Blood vessels from mesoderm
21
Question
What are optic vesicles?
Answer
Lateral forebrain pouches giving rise to eyes
22
Question
What are ossification centers?
Answer
Embryonic regions where cartilage ossification begins
23
Question
What is intramembranous ossification?
Answer
Bone creation from osteoblasts without cartilage
24
Question
What characterizes endochondral ossification?
Answer
Bone produced by ossifying existing cartilage
25
Question
What happens in week 1 of embryonic development?
Answer
Germinal stage: fertilization to blastocyst implantation
26
Question
What forms the zygote initially?
Answer
Single cell from egg and sperm fusion
27
Question
What is a blastocyst?
Answer
50-150 cell structure implanting in uterine wall around day 5
28
Question
When does blastocyst implantation occur?
Answer
Approximately 2 weeks after fertilization
29
Question
What emerges in the 3rd week of development?
Answer
Primitive streak and node inducing neural plate
30
Question
What does the primitive node induce?
Answer
Formation of neural plate for neurulation