Early Embryogenesis and Fertilization

This set of vocabulary flashcards covers the biological terms and developmental stages associated with fertilization and early embryogenesis as described in the lecture notes.

Fertilization

The process of gamete attachment and fusion between a sperm and an oocyte.

Early embryogenesis

The transition from fertilization to a free-living conceptus that can communicate with the uterus.

Acrosome

A structure on the sperm head containing hydrolytic enzymes used during the fusion with the egg plasma membrane.

Cortical granule

Granules located within the egg that release their contents to the egg plasma membrane during fertilization.

Zona pellucida

The thick transparent membrane surrounding a mammalian ovum before implantation.

Ootid

The pronuclear stage after sperm entry when male and female pronuclei are present within the oocyte cytoplasm.

Syngamy

The specific process where the male and female pronuclei fuse.

Zygote

A single-celled unit formed when the pronuclei fuse in syngamy.

Embryo

A term referring to the early developing organism.

Blastomeres

The individual cells generated by the first cleavage division of a two-celled embryo.

Perivitelline space

The space between the zona pellucida and the egg plasma membrane where polar bodies are located.

Morula

An embryonic stage reached by Day 4 consisting of a $16\text{-cell stage}$ to $32\text{-cell stage}$ cluster.

Blastocyst

An embryonic stage occurring at Day 5, composed of the trophoblast and embryoblast.

Trophoblast

The outer layer of cells in a blastocyst that helps form the placenta.

Embryoblast

The inner cell mass of a Day 5 blastocyst.

Polar body

Small haploid cells produced during meiotic divisions (Meiosis I and Meiosis II) that do not develop into ova.