ANHB1101 Lecture Notes - Lecture 31: Blastocoel, Endometrium, Primordial (Band)
3 Jun 2018
School
Course
Professor
Lecture 31
Tuesday, 24 May 2016
8:48 am
Embryogenesis 1
Pregnancy:
• 266 days from the day of fertilization
• 1st trimester
o Point of fertilization -> 12 weeks
o Embryonic period - embryogenesis
o Basic elements of tissues and organs formed
• 2nd trimester
o 12-24 weeks
o Rapid relative growth of foetus
o Organs further developing in complexity
• 3rd trimester
o 24 weeks - to term
o Foetus is laying down more fat
o Towards the end of pregnancy - maturation in foetal tissues in
preparation for birth
Embryology Overview:
• Week 1
o Fertilization
o Journey of zygote into uterus for implantation
• Week 2
o Formation of bilayer embryo
• Week 3
o Development of three-layer embryo
o Destination of the primary germ layers
o Beginning of organogenesis
• Week 4
o Folding occurring
o Formation of placenta
Mechanisms in Embryogenesis:
• Cell division (mitosis)
o Zygote is totipotent - potential to form any cell that exists in the body
o As the cells divide and differentiate they become more specialised -
pluripotent (refinement)
• Induction mechanisms
o Signals from adjacent tissues that induce change
o Cell communication
• Cavity formation (pumping fluid)
o Important for future establishment of geometry of bodies
• Cell migration
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