MCD BIO 138 Lecture Notes - Lecture 9: Tight Junction, Cell Junction, Basement Membrane
4 Jun 2019
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Cellular basis of morphogenesis gastrulation: gastrulation: conversion of cleavage stage embryo to one with primary germ layers & clear body plan (basically formation of stomach) Changes in cell shape, cell-cell interactions and cell-ecm interactions lead to cell rearrangement. New cell combination -> different signaling events/induction. Cell rearrangements form germ layers, allow new interactions e. g. induction. Emergence of the body plan: shape changes lead to clear a/p & d/v axis: body plan: organization of cells resembling final organism when it hatches. Epithelium: arranged in sheets, tightly linked, polarity. Basal: basement membrane (ecm) made by epithelium themselves. Important for cell to know apical-basal polarity: know where to put junctional complex & where to secrete stuff: basement membrane: dense layer of extracellular proteins. So filaments can slide past each other -> rapid contraction & expansion. Regulates flexibility, cell shape change & mobility: microtubules. Epithelium: epithelium contains apical belt of microfilaments. Microfilament constitutes different from in basal levels: longitudinal fibers control cell length.
