Answer Happy

1. List the four major types of somatic receptors and describe the primary stimuli to which they are most sensitive. In which of these are baroreceptors categorized? 2. A) Explain the concepts of 'adequate stimulus' and 'threshold' as they apply to receptors of different types. B) When the membrane potential in a sensory receptor changes, what is (i) the name of the potential, and (ii) the type of potential that occurs (graded or action)? What are two ways that that potential may be transmitted to the brain (i.e., how is the sensory neuron affected)? 3. Draw three touch receptors with overlapping receptive fields; number them 1 – 3. For each receptor, draw separate primary and secondary neurons, so that there are three ascending pathways to the cortex (see Fig. 10.2, p. 311). Based on your drawing, answer the following two questions and explain your reasoning, or use adequate labels on your drawing to support your answer. A) How many distinct regions can the brain distinguish from these three receptors? B) How would your answer change if two of the primary neurons converged onto one secondary neuron? 4. Your brain must be able to distinguish light stimuli from sound, where the stimuli are coming from, as well as their intensities and durations. Explain how each is piece of information is analyzed in order for you to tell a faint, constant light on one side of your body, from a short, loud bang at the other side. (You will probably want to use some of the related terminology from lecture in your answers.) 5. A) Diagram the general pathway of afferent (sensory) signals to the cerebral cortex. B) List three sensory signals that deviate from the general pathway, and explain how they differ from it. c) (i) Group the specific somatosensory modalities of proprioception, temperature, vibration, fine touch, coarse touch, and nociception by their respective afferent pathways, and (ii) diagram (or explain) those pathways. What the heck does 'decussation' mean, anyway? 6. Compare tonic and phasic sensory receptors and provide examples of each. 7. Compare the transmission of a sharp, localized pain to a dull, diffuse one. Include the specific fiber types involved in each, along with their relative sizes and amount of myelination. 8. Briefly explain the difference between pain modulation through ascending and descending pathways. 9. A) Outline the mechanisms involved with descending pathway pain modulation. B) Briefly explain the gate control theory of pain modulation and its similarities to your description in part A. 1