ANSC 3323 Chapter Notes - Chapter 2: Intracytoplasmic Sperm Injection, Pronucleus, Polyspermy
Document Summary
In vivo embryos: syngamy = pronucleus formation and fusion of pronuclei. The 2 pronuclei (pn) fuse, forming one diploid nucleus. In vivo fertilization: completed within 24 hours of ovulation, 400-600 million sperm deposited during ejaculation. Only about 200 sperm reach the fertilization site. Most degenerate and are absorbed by female reproductive tract. In vitro fertilization: after oocyte maturation, co-culture of capacitated sperm (heparin, caffeine) with matured oocytes, takes about 6 hours. Shorter low fertilization rates: 100-200k sperm per 25 oocytes, sperm penetrates the eggs as in in vivo fertilization, remove sperm, culture presumptive zygotes. Frozen semen usually used for ivf and motile sperm need to be isolated after thawing. Stages of ivf: matured oocytes + sperm = fertilized, matured oocytes, denuded; intra-cytoplasmic sperm injection. Steps of embryo development in cattle: 1 cell (oviduct, 4 cells (oviduct, 8 cells (oviduct) Mzt occurs during 4-8 cell transition: morula (traveling from oviduct to uterus) Compaction occurs here: early blastocyst (uterus, expanded blastocyst.
