Developmental Periods And Terminology Flashcards
When is the embryonic period?
0-8 weeks
When is the foetal period?
9-40 weeks
When is the developing foetus most prone to deformation?
In the embryonic period
When is the neonatal period?
0-4 weeks post natal
When is infancy?
4-52 weeks postpartum
When is childhood?
2 years - puberty
When is adolescence?
11-19 years
When does adulthood begin?
Around 19 years
What is the purpose of the Carnegie stages of development?
To standardise the developmental stages across species
What are the 5 early events in embryology?
1- gametogenesis
2 - fertilisation
3 - cleavage
4 - gastrulation
5 - formation of the body plan
What is the organogenesis?
Formation of the organ systems that occurs in an overlapping timeline
What does cranial refer to?
The brain end
What does caudal refer to?
The tail end
What does dorsal refer to?
Towards the back
What does ventral refer to?
Towards front
What does the transverse cut divide?
Cranial and caudal ends
What does sagittal cut?
Between right and left
What does the coronal cut?
Into ventral and dorsal
What is cell division?
The increase in the number of cells to influence shape and growth
What is differentiation?
Changes in appearance and structure to specialise cells
What is cell attachment?
Development of physical and functional linkages to allow formation of tissue
What is apoptosis?
Programmed cell death to create space and cavities within the body
What is induction?
The ability of cells to cause others to differentiate through chemical signals
What is cell migration?
Movement between locations
What are the secondary processes of development?
Axis formation, folding/rotation, increase/decrease in mass or dimension
Where is sonic hedgehog located?
Ventrally
Where are cells more likely to express ventral characteristics?
Closer to sonic hedgehog
What des folding and rotation allow?
Development of the disc to a tube and alteration of mass and dimension through hypertrophy and hyperplasia
What is hypertrophy?
Growth in size
What is hyperplasia?
Growth in numbers
What is teratology?
The study of abnormal development
What can cause birth defects?
Genetic factors, environmental factors and multi factorial inheritance
What are malformations?
Intrinsic abnormal developmental defects. Trisomy 18, Edward syndrome
What is disruption?
Extrinsic interference on normal development. (Teratogenic drugs, virus)
