Lab 2 Flashcards
isolecithal
having a small amount of yolk that is evenly distributed throughout the cytoplasm of an egg
Germinal vessicle
the enlarged nucleus of an immature egg cell, or oocyte, before meiosis. It’s a large, spherical structure that contains chromatin (DNA) and the nucleolus.
Fertilization membrane
physical barrier to sperm after oocyte is fertilized
blastula
an animal embryo at the early stage of development when it is a hollow ball of cells.
Radial clevage
a characteristic feature in the early embryonic development of deuterostomes. It is one of the simplest cleavage patterns in which the successful division planes are at 90° relative to each other. Thus this cleavage results in daughter cells that are located exactly on top of one another.
Blastulation
an early stage of embryonic development where a fertilized egg forms a ball of cells with a fluid-filled center
Blastula
an animal embryo at the early stage of development when it is a hollow ball of cells.
blastocoel
the cavity ay the center of the blastula
Gastrulation
The embryo transforms from a blastula, a single-layered ball of cells, into a gastrula, a three-layered ball of cells
vegetal pole
the portion of an ovum opposite the animal pole, containing most of the yolk and little cytoplasm.
invagination
the action or process of being turned inside out or folded back on itself to form a cavity or pouch.
Archenteron
the rudimentary alimentary cavity of an embryo at the gastrula stage.
blastopore
a temporary opening in the surface of an embryo that develops during gastrulation. It’s the first opening in the embryo, and it eventually becomes the mouth or anus.
animal pole
the region with less yolk and more active cytoplasm, where the nucleus is located and where cell division occurs rapidly
coelomic sacs
fluid-filled sacs that form during embryonic development and are part of the coelom
enterocoely
the process by which the coelom, or body cavity, forms in some animal embryos
ectoderm
the outermost layer of the three germ layers, which gives rise to numerous outer layers of the body, including the epidermis, hair, nails, oral epithelium, cornea, and olfactory epithelium
mesoderm
the middle layer of an embryo, and is one of the three primary germ layers. It’s a source of many tissues and organs, including bone, muscle, blood, and the circulatory system.
endoderm
Endoderm cells give rise to certain organs, among them the colon, the stomach, the intestines, the lungs, the liver, and the pancreas.
peritoneal structures
organs contained in the smooth sheet of peritonium
deuterostromos
deuterostomous animals are those whose blastopore develops into the anus,animals that develop with the anus forming before the mouth. The name comes from the Greek words deuteros, meaning “second”, and stoma, meaning “mouth
bipinnaria larva
a free-swimming, bilaterally symmetrical larva that is the first stage in the development of most starfish.
mesolethical
eggs with a moderate amount of yolk that is concentrated in one hemisphere
hoboblasic cleavage
a type of cell division that occurs when an entire fertilized egg divides into blastomeres
