AP BIOLOGY

Detailed explanation-1: -Paracrine signaling Often, cells that are near one another communicate through the release of chemical messengers (ligands that can diffuse through the space between the cells). This type of signaling, in which cells communicate over relatively short distances, is known as paracrine signaling.

Detailed explanation-2: -Paracrine signaling allows cells to communicate with their immediate neighbors via secretion of signaling molecules. The signal only triggers a response in nearby target cells as the signal molecules degrade quickly or are inactivated by nearby cells if not taken up.

Detailed explanation-3: -Paracrine signaling between the mesenchymal and epithelial cells and interactions with the extracellular matrix (ECM) are the major components of the stem cell niche that modulates cell behavior [1, 9].

Detailed explanation-4: -Paracrine signaling occurs between local cells where the signals elicit quick responses and last only a short amount of time due to the degradation of the paracrine ligands.