AP BIOLOGY

Detailed explanation-1: -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: -In paracrine signaling, a molecule released by one cell acts on neighboring target cells. An example is provided by the action of neurotransmitters in carrying signals between nerve cells at a synapse.

Detailed explanation-3: -These results suggest that in human islets, acetylcholine is a paracrine signal secreted from alpha cells. Once released, it is likely that acetylcholine acts only locally on adjacent endocrine cells.

Detailed explanation-4: -In paracrine signaling, they act on nearby cells. Autocrine signals include extracellular matrix molecules and various factors that stimulate cell growth. An example of paracrine signals is the chemical transmitted from nerve to muscle that causes the muscle to contract.

Detailed explanation-5: -Whereas endocrine factors (hormones) travel through the blood to exert their effects, paracrine factors are secreted into the immediate spaces around the cell producing them.