Survey of Embryonic Development Flashcards
Name the structures
- Fertilization (zygote)
- Blastomeres 2 cells (cleavage)
- Bastomeres 4 cells (cleavage)
- Blastomeres 8 cells (cleavage)
- Morula (blastomeres 32 cells) “solid ball”
- Blastula (hollow ball)
- Blastocyst/ gastrula
- Implanted blastocyst
What is happening in 1?
Fertilization: sperm and ovum
Time zero
What is the term for 2 and what is its time duration?
Embryo
Weeks 3-9
What is the term for 3? How long does this stage last?
Fetus.
From 9 weeks to birth
What is happening in 4? What is the time?
Implantation into uterine wall
Week 1
Label
- Oocyte
- Zygote (fertilized egg)
- 4 cell stage
- Morula
- Blastocyst
- Implanting blastocyst
Label
- Endometrium
- Uterine endometrial epithelium
- Inner cell mass
- Trophoblast (outside cells)
- Blastocyst cavity
- Lumen of uterus
Label
- Endometrial stoma with blood vessels and glands
- Syncytiotrophoblast (“legs”)
- Cytotrophoblast
- Inner cell mass (future embryo)
- Trophoblast (outside of blastocyste)
- Lumen of uterus
Label
- Inner cell mass = embryoblast
- Trophoblast = outside cells
- Blastocyst cavity
- Blastocyst
Label
- Amnion
- Allantois
- Chorion
- Yolk sac
- Yolk (nutrient)
- Albumen
- Shell
- Amniotic cavity with amniotic fluid
- Embryo
Label
- Decidau basalis (bottom of mom’s uterus- where belly button forms)
- Maternal blood
- Chorionic villus
- Umbilical blood vessels in umbilical cord
- Amnion
- Amniotic cavity
- Yolk sac
- Chorion
- Decidua capsularis (cover of embryo)
What is the purpose of the amnion?
Encases and protects embryo against mechanical and temperature, trauma
What is the purpose of the yolk sac?
•Yolk sac: transfers nutrients to embryo. Replaced by placenta in humans.
What is the purpose of the allantois?
•Allantois: repository of embryo wastes. Replaced by placenta in humans.
What are the three germal layers?
- •Ectoderm: nervous tissues, epidermis and melanocytes.
- •Mesoderm: bones, muscles, mesenchyme, reproductive system, urinary system.
- •Endoderm: digestive system, respiratory system, endocrine system.
What does the ectoderm contribute to?
•Ectoderm: nervous tissues, epidermis and melanocytes.
What does the mesoderm contribute to?
•Mesoderm: bones, muscles, mesenchyme, reproductive system, urinary system.
What does the endoderm contribute to?
Endoderm: digestive system, respiratory system, endocrine system