Embryogenesis and Development Flashcards
Region of fallopian tube where fertilization occurs
Ampulla
Cortical reaction
Release of calcium ions into egg membrane to depolarize and prevent further fertilization of ovum and increase metabolic rate of new zygote
Dizygotic (fraternal) twins
Fertilization of two different eggs released during one cycle by two different sperm
Monozygotic (identical) twins
One zygote splits in two
Indeterminate cleavage
Cells that can still develop into complete organisms
Determinate cleavage
Cells with fates already determined, committed to differentiating into a type of cell
Morula
Next step after embryo and before blastula
Blastulation
Morula becomes blastula
Blastocoel
Inner cavity in a blastula
Trophoblast cells
Surround blastocoel and give rise to chorion and placenta
Inner cell mass
Protrudes into blastocoel and gives rise to organism itself
Chorion
Extraembryonic membrane that develops into placenta
Chorionic villi
Form from trophoblasts and penetrate the endometrium for interface between maternal blood supply and embryo
Umbilical cord
Has one vein that carries oxygenated and nutrient-rich blood from placenta to embryo, and two arteries that carry deoxygenated blood and waste to placenta from embryo
Yolk sac
Supports the embryo until placenta is functional, site of early blood cell development
Allantois
Early fluid exchange between embryo and yolk sac
Amnion
Thin, tough membrane filled with amniotic fluid that surrounds allantois, fluid serves as shock absorber during pregnancy
Gastrulation
Generation of 3 distinct cell layers after blastulation, making a gastrula
Archenteron
Membrane invagination into blastocoel that leads to gut
Blastopore
Opening of archenteron
Differential blastopore development
Anus in deuterostomes and mouth in protostomes
Ectoderm
Outermost germ layer that gives rise to skin, hair, nails, nose, mouth, eye, nervous system, adrenal medulla, ear