Principles of Embryology Flashcards
In-utero human development
9 months
3 trimesters
Week 0-3 = Embryo
Week 3-8 = Embryonic period
Week 9-40 = Foetal Period
Spermogenesis
Male gamete formation
Occurs a puberty and throughout life
Production rate - 6.5million sperm per gram
Outcome –> 22 + X or 22+Y
Spermatogonia
Primary spermatocyte
Secondary spermatocyte
Spermatids
Oogenesis
Female Gamete formation
Starts in development and ends at menopause
Week 28-30 - Primary oocyte being meiosis but arrest until puberty
Oogina
Primary Oocyte
Secondary Oocyte
Polar Body & Oocyte
Outcome –>22+X
Trisomy 21 - Down Sydnrome
Aneuploidy
Additional copy of Chr21
Non-disjunction
Fertilisation
Gamete union
Zygote formation - diploid, single cell embryo, sex determination
Polyspermy - membrane depolarises, zona pellucida (harden)
Cleavage
Period of rapid mitotic cell division
No increase in size
Formation of Morula –> Blastocyst
Trophoblast
Epiblast
Gastrulation
Week 3
Ectoderm
Mesoderm
Endoderm
Body axes established
Primitive streak
Formation of the Body Plan
Embryonic folding
Both directions
Organogenesis
Formation of organs and organ systems
Week 5-8
COntinue to develop through foetal period
Foetal Period
Growth and weight gain (2nd and 3rd trimester)
7.7lb at birth
Tissues mature and become functional
Overt sexual differentiation
Bone laid down
CNS connections
Cartilage
Cranial and Caudal
Ventral and Dorsal
Top and Bottom
Front and Back
Primary Processes - Zygote to Human (6)
Cell Division
Differentiation
Cell attachment
Apoptosis
Induction
Cell migration
Secondary Processes (2)
Axis formation/Polarity
Folding/Rotation
Control of Development
Genetic
Epigenetic
Environment
