In a covalent bond, electrons are shared between atoms. In an ionic bond, electrons are transferred between atoms.

TLS Online TPP Program

#Id: 7014

#Unit 5. Developmental Biology

The types of the intracellular mechanisms used by a given stem cell are in part the downstream net result of the extracellular stimuli in its niche.

TLS Online TPP Program

#Id: 7015

#Unit 5. Developmental Biology

Physical mechanisms of influence, including Structural & adhesion factors within the extracellular matrix that support the cellular architecture of the niche. 

TLS Online TPP Program

#Id: 7016

#Unit 5. Developmental Biology

Differences in cell-to-cell and cell-to-matrix adhesions as well as the cell density within the niche can alter the mechanical forces that influence stem cell behavior.

TLS Online TPP Program

#Id: 7017

#Unit 5. Developmental Biology

Chemical regulation of stem cells takes the form of secreted proteins from surrounding cells that influence stem cell states and progenitor differentiation through endocrine, paracrine, or juxtacrine mechanisms.

TLS Online TPP Program

#Id: 7018

#Unit 5. Developmental Biology

In many cases, signaling factors maintain the stem cell in an uncommitted state.

TLS Online TPP Program

#Id: 7019

#Unit 5. Developmental Biology

Once stem cells become positioned farther from the niche, signaling factors cannot reach them, and differentiation commences.