development quiz

Corona radiata

one of the barriers to initial sperm penetration. It is a layer of cells that chemically attracts sperm

Zona pellucida

one of the barriers to initial sperm penetration. it is a highly protective layer surrounding secondary oocyte

Protostomes

becomes the mouth

Deuterostomes

becomes the anus

extraembryonic membranes

yolk sac, amnion, chorion, allantois

Yolk sac

provides nutrients to embryo

amnion

protection and shock absorption

Chorion

gas exchange

allantois

collects waste from embryo

Preprogrammed theories

aging is at least partly genetically preprogrammed

damage control theories

aging is caused by accumulation of cellular damage over time. The body has to compensate for damage by aging

Fertilization

the union of two haploid nuclei (sperm cells and a egg)

Morula

a simple, solid, tiny ball of cells resulting from about 16 cleavages

Blastula

a hollow ball of cells resulting from 32 total cleavages

Acoelomate

organisms that lack a true body cavity

blastopore

the opening into the archenteron; first embryonic opening