notes - 3.26.09

notes - 3.26.09 - Human gastrulation: Different in...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Human gastrulation: - Different in mammalian gastrulation: starts after blastocyst has implanted into  uterus - After the blastocyst has implanted, cells in inner cell mass begin to undergo  gastrulation - Epiblast cells - Look up what type of movement epiblast cells undergo (in relation to frog and sea  urchin) 1. Blastopore formation a. Gastrulation begins 180° from site of sperm entry b. How do cells choose fates before gastrulation? i. Dorsal-ventral axis in frog ii. A frog’s mother sets up the initial axis of polarity with animal vs vegetal  pole Outline of frog gastrulation: - Unfertilized egg o Sperm always enter at point in animal pole - Fertilized egg - Midblastula: 4000 cells Sperm entry is the critical asymmetric cue in setting up the dorsal-ventral axis of the frog  Xenopus - Triggers the rotation of the outer cortex Outer region of egg = cortex Inner cytoplasm (vegetal has yolk, animal does does Outer cortex rotates 30° with respect to innter cytoplasm This rotation sets up a new area of interaction: the gray crescent = junction of vegetal coretex  with animal cytoplasm Gray crescent = where gastrulation initiates.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 4

notes - 3.26.09 - Human gastrulation: Different in...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online