EMBRYOLOGY Flashcards
what is differentiation?
specialisation
change in appearance and structure
adoption of new functions
what is cell arrangement?
physical and functional linkages
formation of tissues
what is apoptosis?
programmed cell death in response to specific signals
what is induction?
the ability of one cell type to cause another to differentiate
what is cell migration?
movement from one location to another
what causes angelman syndrome?
Deletion on maternal chromosome 15
what causes prader willi syndrome?
Deletion on paternal chromosome 15
what is cell division?
increase in the number of cells
what are the six phases of embryogenesis?
gametogenesis fertilisation cleavage gastrulation formation of a body plan organogenesis
what causes trisomy 21?
additional copy of chromosome 21 caused by nondisjunction
what is a zygote?
single cell embryo, diploid
what is cleavage?
period of rapid cell division but with no increase in size
how is a body plan formed?
embryonic folding
what is organogenesis?
formation of organs and organ systems
what occurs during the foetal period? (5)
growth and weight gain tissues mature and become functional overt sexual differentiation bone laid down connections made in CNS
what are the primary processes for formation of an embryo? (6)
cell division differentiation cell attachment apoptosis induction cell migration
what are the secondary processes in the formation of an embryo?
axis formation/polarity
folding/rotation
what does meiosis cause in gametogenesis?
genetic variation
how long does spermatogenesis take and when does it begin?
64 days
what is oogenesis?
the formation of female gametes
when is oogenesis arrested and restarted?
arrested in prophase at weeks 28-30
restarted in puberty
what is nondisjunction?
chromosome doesn’t split and both are pulled to one side, meaning theres three copies when joined with the other gamete
what is established at gastrulation and what happens if this goes wrong?
body axes are established
structures can be in the wrong place
what is posterior called in an embryo?
dorsal
what is anterior called in an embryo?
ventral
what is superior called in an embryo?
cranial
what is inferior called in an embryo?
caudal
what is weeks 3-8 of development called?
embryonic period
what is weeks 9-40 of development called?
foetal period
what is fertilisation?
fusion of sperm and an oocyte
what is formed by cleavage over days 1-4?
morula and then a blastocyst
what is gastrulation?
formation of the germ layers at week 3
when does an embryo have a large gain in height and weight?
height = 2nd trimester weight = 3rd trimester
what is weeks 0-3 of development called?
conceptus/embryo
what week is critical for birth defects?
5
what is gametogenesis?
the formation of gametes
what is a gamete?
a haploid sex cell (23 chromosomes)
what stages make up gametogenesis?
mitosis and meiosis
what is spermatogenesis?
the formation of male gametes
what are the germ layers from outer to inner?
ectoderm
mesoderm
endoderm
