embryology Flashcards
(21 cards)
stages of development
egg&sperm –> fertilization –> cleavage –> gastrulation –> organogenesis –> metamorphosis
cleavage
division of zygote into smaller cells every 12-24 hours
morula
solid ball of cells
blastula
hollow ball of cells
gastrulation
- the movement of cells to create germ layers
- starts at dorsal lip
- results in gastrula
3 germ layers
ectoderm, mesoderm, endoderm
ectoderm
skin, nervous system, teeth, lens
mesoderm
blood, skeletal, muscular, circulatory, and lymphatic system
endoderm
linings of respiratory, excretory, reproductive, and digestive system
deuterosomes
anus first
protostomes
mouth first
differentiation
- all cells have the same genes
- due to the expression or silencing of genes for specific proteins, determined by location of cells, and signaled by the environment
- signals are the same for many organisms
noggin and chordin
induce mesoderm to change to muscle and notochord (spine)
retinoic acid
regulates limb development and regeneration
homeotic selector genes
- genes whose expression affects the overall body plan / sequences
- bithorax/antennapedia are due to mutations in drosophila
lineage map
- tracing the cells during development and creating a map
- allows us to know what cells will become what structures
organogenesis
- organ formation begins
- apoptosis and gene activation/silencing are very important
apoptosis
hollows out blood vessels, creates fingers and toes, necessary for proper brain development and more
complete metamorphosis
egg larva pupa adult butterfly, mosquito, beetles, frogs
aging
- depends on genes and environment
- as we age our cells are less likely to divide and more likely to die
embryonic stem cell retrieval
~100 cells total
blastocyst
