DOH253 Lecture Notes - Lecture 1: Zona Pellucida, Primitive Streak, Amniotic Sac
Document Summary
Development - fertilisation to birth, infancy (first year), childhood (2 years to puberty), adolescence (11-19 years) Single cell zygote is fertilised by a sperm. Cleavage: the cell doesn"t grow but begins to split while in zona pellucida. After split into about 32 the cell becomes known as the morula. The outside cells become a bit different and are known as trophoblasts. And the inside cells are known as embryoblasts. The inside cells then begin to clump more and cluster at one end known as the inner cell mass blastocoel. Thus forming a cavity on the other end known as the blastocoel. The blastocyst is the name for the zona pellucida with the inner cell mass and. Blastulation - zona pellucida starts to disintegrate away. Eventually the zona pellucida is completely lost - important for implantation. The inner cell mass then begins to look different. Another cavity on the outer edge is formed which is called the amniotic cavity.
