PSYC 251 Lecture Notes - Lecture 2: Spina Bifida, Neural Tube Defect, Programmed Cell Death
Document Summary
Important to proper development ie. webbing and tail must die off: hormonal effects, all fetuses are born so that they can become male or female, presence of testosterone is what allows for males to develop. Germinal period: a blastocyst is a hollow sphere with inner cell mass, <1 mm in diameter, identical twins occur due to a splitting of inner cell bass, complete implantation marks the end of the germinal period. January 16, 2018: takes a week for the blastocyst to reach the uterus, two weeks total. Implantation takes about a week: differentiation starts after implantation. Fetus at 11-12 weeks: fingers and external genitalia are fully formed, reflexes present and moving a lot but still not felt, organs, muscles, and nervous system are becoming organized and connected. Fetus at 16 weeks: mom begins to feel babies" first kicks, beginning of period of lower body growth, head is less disproportional to rest of body. Fetus at 18 weeks: starts sucking thumb.