embryology Flashcards
1
Q
stages of development
A
egg&sperm –> fertilization –> cleavage –> gastrulation –> organogenesis –> metamorphosis
2
Q
cleavage
A
division of zygote into smaller cells every 12-24 hours
3
Q
morula
A
solid ball of cells
4
Q
blastula
A
hollow ball of cells
5
Q
gastrulation
A
- the movement of cells to create germ layers
- starts at dorsal lip
- results in gastrula
6
Q
3 germ layers
A
ectoderm, mesoderm, endoderm
7
Q
ectoderm
A
skin, nervous system, teeth, lens
8
Q
mesoderm
A
blood, skeletal, muscular, circulatory, and lymphatic system
9
Q
endoderm
A
linings of respiratory, excretory, reproductive, and digestive system
10
Q
deuterosomes
A
anus first
11
Q
protostomes
A
mouth first
12
Q
differentiation
A
- 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
13
Q
noggin and chordin
A
induce mesoderm to change to muscle and notochord (spine)
14
Q
retinoic acid
A
regulates limb development and regeneration
15
Q
homeotic selector genes
A
- genes whose expression affects the overall body plan / sequences
- bithorax/antennapedia are due to mutations in drosophila
