Chp. 10 1.2 Touch

Q: What do cutaneous receptors detect?

A: Touch, pressure, pain, cold, heat.

Q: What is a receptive field?

A: Skin area that changes neuron firing when touched.

Q: What affects field size?

A: Receptor density.

Q: More receptors = ?

A: Smaller field, better touch accuracy.

Q: Fewer receptors = ?

A: Larger field, worse touch accuracy.

Q: Cold receptors — location and traits

A: Upper dermis, > abundance than heat receptors, some respond to menthol

Q: Warm receptors — location and traits

A: deeper dermis, excited = warming, inhibited = cooling, doesn’t sense pain

Q: What stimulates nociceptors (pain receptors)?

A: Chemicals released by damaged tissues.

Q: What type of neurons carry sharp, sudden pain?

A: Myelinated neurons.

Q: What type of neurons carry dull, persistent pain?

A: Unmyelinated neurons.

Q: Which receptors detect painful heat?

A: Capsaicin receptors.

Q: What causes acute itch (pruritus), and how is it treated?

A: Histamine release from mast cells and basophils; responds to antihistamines.

Q: What causes chronic itch, and does it respond to antihistamines?

A: Other chemicals; does not respond to antihistamines.

Q: Referred pain — what is it?

A: Pain felt in wrong place (e.g. heart pain interpreted as arm, gallbladder → back).

Q: Why does referred pain happen?

A: Somatic + visceral neurons share same interneuron.

Q: Why does rubbing injury help?

A: Gate Control Theory.

Q: Gate Control — how does it work?

A: Touch/pressure signals use thick axons → faster → block pain.