Nociceptors are found in which tissues?

• A. Skin, bone, muscle, organs, heart
• B. Brain only
• C. Spinal cord only
• D. Blood vessels only

Answer: (A)

Nociceptors are pain-detecting endings that sit in tissues across the body so you can sense potential damage. They are distributed in the skin, bone, muscle, and many organs—including the heart and blood vessels. The brain tissue itself doesn’t contain nociceptors, which is why pain isn’t felt from brain tissue directly; pain signals originate in peripheral tissues and travel to the brain. Because this option lists the tissues where nociceptors actually reside, it best reflects their widespread distribution. The other options imply nociceptors are restricted to brain, spinal cord, or blood vessels alone, which doesn’t match their true, broad presence.