Question

Which of the following accurately describes the two different classes of local regulators and their differences?

A. The two classes are autocrine and paracrine regulators, with autocrine acting on nearby cells and paracrine acting on the same cell that secretes them.
B. The two classes are endocrine and exocrine regulators, with endocrine acting on distant cells through the bloodstream and exocrine acting on nearby cells.
C. The two classes are hydrophilic and hydrophobic regulators, with hydrophilic regulators acting on cell surfaces and hydrophobic regulators entering cells to act on intracellular receptors.
D. The two classes are catabolic and anabolic regulators, with catabolic regulators promoting breakdown processes and anabolic regulators stimulating synthesis processes.

Answer 1

There are four classes of chemical signaling: autocrine, paracrine, endocrine, and direct signaling through gap junctions.

Step-by-step explanation:

There are four classes of chemical signaling in multicellular organisms: autocrine signaling, paracrine signaling, endocrine signaling, and direct signaling through gap junctions. Autocrine signaling occurs when a cell targets itself, whereas paracrine signaling acts on nearby cells. Endocrine signaling uses the circulatory system to transport signals to distant cells, and direct signaling occurs between adjacent cells through gap junctions.