ACB 330 Lecture Notes - Lecture 7: Blastocoel, Cytoplasm, Morula

• School: U of S
• Department: Anatomy and Cell Biology
• Course: ACB 330
• Professor: Kulyk William

Document Summary

Cleavage: period of rapid cell divisions post fertilization. By dna double with each round of mitosis. Early cleavage done by: mrna/proteins made early and stored by oocyte. Patterns: vary with different groups based on yolk and genetic factors. Holoblastic cleavage: cleavage furrows extend through entire egg. Radial: sea cucumber: meridional (1/2): equatorial (3): 4-8 alternated back and forth. Displaced radial: amphibian: meridional (1/2): equatorial (3:on top 1/3rd of cell): meridional (4): equatorial (5: on either side of 3). Bilateral: tunicates: bilateral plane of symmetry down the center. Not even division though due to cytoplasmic concentrations. Rotational: mammals: meridional (1): meridional and equatorial (2): blastomeres divide asynchronously: @ 8 cell stage (cid:862)compaction(cid:863) increase in e-cadherin (makes tight junctions). After this: (cid:272)ells either divide parallel or perpe(cid:374)di(cid:272)ular to (cid:862)a(cid:454)is of (cid:373)orula(cid:863). This (cid:272)reates a(cid:374) outside ri(cid:374)gs a(cid:374)d i(cid:374)side (cid:272)ells. Inner cells: hippo active pluripotency transcribed inner cell mass forms embryo/yolk.