Learning Objectives for chapter 12

1.         What are the primary types of skin found on the human body? (Note that I mentioned three types in class although your book discusses two—you should include all three in your answer.)

2.         What are the types of mechanoreceptors found in skin tissue? Which are rapidly adapting? Which are slowly adapting? Why are there such differences?

3.         How does a Pacinian corpuscle respond to stimuli that are transient and stimuli that are sustained? What happens if you remove the capsule surrounding the nerve ending in a Pacinian corpuscle?

Note: In class I said that Pacinian corpuscles respond to deep pressure and not to vibration, however your book notes that they respond to vibration. Both of those are true statements—their unique structure, location, and rapid adaptation rate make them very well-suited to respond to deep pressure that is transient, especially if it has a rapid onset and offset. It’s actually more complicated than either answer leads you to believe, but for now, if you want to remember something, remember that they respond to deep pressure and vibrations of a specific frequency.

4.         What is two-point discrimination?

5.         What is the difference between fibers designated Aa, Ab, Ad, & C?

6.         How many groups of spinal nerves are there? What is a dermatome?

7.         Be able to diagram, outline, or describe both the dorsal column-medial lemniscal pathway and the spinothalamic pathway (your book discusses the spinothalamic pathway under the heading of ascending pain pathways).

8.         What is the trigeminal pathway?

.           Explain the concept of cortical somatotopy. Where on the somatosensory cortex would you find the location for the leg? What about the face? Why is it important to know the locations of these and other areas?

9.         How would you describe the plasticity of the somatosensory cortical map?

10.       What is astereognosia? Where would the damage that produces this condition be located? How is this like other conditions we have studied? You should also be able to relate asterognosia to other agnosias, such as prosopagnosia (although you won’t find prosopagnosia in this chapter).

11.       What are nociceptors? What are the different types of nociceptors and to what kinds of stimuli do they respond? Why is it important to emphasize that pain and nociception are not the same thing?

12.       How does transduction occur in nociceptors?

13.       What is hyperalgesia? What can cause it to occur?

14.       What are bradykins, prostaglandins, and substance P?

15.       You will need to know the pathway for pain information (slow pain and fast pain). You will also need to know what role the trigeminal pathway plays in pain.

16.       What is afferent regulation of pain? What about descending regulation?

17.       What are the endogenous opioids?

18.       What are the few general principles known about thermoreceptors? In other words, if you were to summarize the basic points in just a few sentences, how would you do it?

19.       What is the temperature pathway?

20.       Does the somatosensory system use a labeled-line or across-fiber pattern of firing (or both)?

You should also have an understanding of various pain-relief mechanisms (both endogenous and exogenous—endogenous=the body’s own mechanism; exoginous=something from the outside, such as aspirin, local anesthetics, and so on). And you should have a brief, general understanding of chronic pain syndromes such as causalgia, neuralgia, and phantom pain.