QUESTION 20Some of the stem cells in bone become osteoclasts during differentiation. Researchers have shown that chemical signals called cytokines arereleased into the extracellular fluid by bone stem cells in response to environmental stimuli. The researchers also have shown that the cytokinesinduce these same bone stem cells to differentiate into osteoclasts. This example illustrates how a(n).signal functions in the human body.O a. autocrineb. hormoneO c. paracrineO d. juxtacrinee. intracellular

Some of the stem cells in bone become osteoclasts during differentiation. Researchers have shown that chemical signals called cytokines are released into the extracellular fluid by bone stem cells in response to environmental stimuli. The researchers also have shown that the cytokines induce these same bone stem cells to differentiate into osteoclasts. Meaning of the key terms: osteoclast: breaks or degrades the bone cells for remodeling of the bone. differentiation: grow in number , shape and size bone stem cells: germ cells that give rise to bone cells. In Autocrine signaling, the target cells are the same producing cells, The signaling molecules bind to the receptors present on its surface to produce an effect. Here the stem cells differentiate into osteoclasts. In paracrine signaling, the target cell is nearby the chemical-producing cell. Signaling molecules diffuse to nearby cells. Here, it is talking about cytokines that are released into extracellular space, so it would not be intracellular signaling. Therefore other options are incorrect.Option a) is the correct answer. This example illustrates how an Autocrime signal functions in the human body.