AP BIOLOGY

Detailed explanation-1: -This type of signaling, in which cells communicate over relatively short distances, is known as paracrine signaling. Paracrine signaling allows cells to locally coordinate activities with their neighbors.

Detailed explanation-2: -Hormones travel the large distances between endocrine cells and their target cells via the bloodstream, which is a relatively slow way to move throughout the body. Because of their form of transport, hormones get diluted and are present in low concentrations when they act on their target cells.

Detailed explanation-3: -Depending on the ligand’s origin (from the same cell, from the neighbour cell or from far distance), recptor-ligand interaction and signaling pathway activation is classified into four different types: autocrine, endocrine, paracrine and juxtacrine.

Detailed explanation-4: -In endocrine signaling, the signaling molecules (hormones) are secreted by specialized endocrine cells and carried through the circulation to act on target cells at distant body sites.