Question

which type of signaling involves a chemical messenger that influences the activity of the cell that releases it?

endocrine signaling

exocrine signaling

paracrine signaling

autocrine signaling

Explanation:

To solve this, we analyze each option:

• Endocrine signaling: Chemical messengers (hormones) travel via bloodstream to distant cells, not the releasing cell.
• Exocrine signaling: Involves secretion into ducts (e.g., sweat, digestive enzymes), not signaling the releasing cell.
• Paracrine signaling: Chemical messengers act on nearby cells, not the cell that released them.
• Autocrine signaling: The cell releases a chemical messenger that acts on itself (the releasing cell). This matches the description.

Answer:

D. Autocrine signaling