Ch. 6.2. Mechanical senses Flashcards
People with damage to the vestibular system have trouble
reading street signs while walking. Why?
The vestibular system enables the brain to shift eye movements to compensate for changes in head position. Without feedback about head position, a person would not be able to correct the eye movements, and the experi- ence would be like watching a jiggling book page.
How do jalapeños produce a hot sensation?
Jalapeños and other hot peppers contain capsaicin, which stimulates receptors that are sensitive to painful heat.
In what way is somatosensation several senses instead of one?
We have several types of receptors, sensitive to touch, heat, and so forth, and different parts of the somatosensory cortex respond to different kinds of skin stimulation.
What evidence suggests that the somatosensory cortex is
essential for the conscious perception of touch?
People are conscious of only those touch stimuli that produce sufficient arousal in the pri- mary somatosensory cortex. Also, cells in the somato- sensory cortex respond to what someone experiences, even if it is an illusion.
How do the responses to skin sensations differ between the somatosensory cortex and the insular cortex or the anterior
cingulate cortex?
The somatosensory cortex is necessary for conscious perception of the location and type of skin sensation. The insular cortex and anterior cingulate cortex respond to the pleasantness.
Suppose you suffer a cut through the spinal cord on the right side only. For the part of the body below that cut, will you lose pain sensation on the left side or the right side? Will you lose touch sensation on the left side or the right side?
You will lose pain sensation on the left side of the body because pain information crosses the spinal cord at once. You will lose touch sensation on the right side because touch pathways remain on the ipsilateral side until they reach the medulla.
In what ways are hurt feelings similar to physical pain?
Hurt feelings activate the cingulate cortex, just as physical pain does. Also, paracet decreases hurt feelings (as well as pleasant feeling).
Why do opiates relieve dull pain but not sharp pain?
Endorphins block messages from the thinnest pain fibers, conveying dull pain, but not from thicker fibers, carrying sharp pain
How do the pain-relieving effects of cannabinoids differ
from those of opiates?
Unlike opiates, cannabinoids exert most of their pain-relieving effects in the peripheral nervous system, not the CNS.
Which aspect of pain is most responsive to relief by
placebos?
Placebos primarily relieve the emotional aspect of pain.
How do ibuprofen and other nonsteroidal anti-inflamma- tory drugs decrease pain?
Antiinflammatory drug blocks the release of chemicals from damaged tissue. Which would otherwise magnify the effect on pain receptors.
In what way is chronic pain like memory?
A barrage of stimulation to a neuron can potentiate its synaptic receptors so that they respond more vigorously to the same input in the future. That mechanism is central to learning and memory, but unfortunately, pain activates the same mechanism. A barrage of painful stimuli potentiates the cells responsive to pain so that they respond more vigorously to similar stimulation in the future
Do opiates increase or decrease itch sensations?
Increases itching by blocking pain receptors.
Suppose someone suffers from constant itching. What kinds
of drugs might help relieve it?
antihistaminer og capsaisin
In which of these ways do coldness receptors differ from heat receptors?
Coldness receptors respond to a change in tempera- ture, not to the absolute temperature.
