48_lol_ns_sensory.docx Bio 48 - Human Physiology Biology 48 - Human Physiology Lecture Summary Sheet - Norris Nervous System: Sensory Physiology I. Definitions A. Stimulus B. Sensation C. Perception II. General Characteristics of Sensory Systems A. Basic model 1. stimulus à dendrite 2. stimulus à accessory structure à dendrite 3. stimulus à transducer cell à dendrite B. Receptor Types 1. Mechanoreceptors 2. Chemoreceptors 3. Thermoreceptors 4. Photoreceptors 5. Nociceptors (pain) C. Specificity 1. Modality / Adequate stimulus 2. Pathway D. Stimulus Localization / Amplitude 1. Receptive Field 2. Lateral Inhibition 3. Action Potential Frequency / Summation E. Adaptability 1. Tonic Receptors 2. Phasic Receptors III. General Senses A. Touch / Pressure (cutaneous & visceral) 1. Pacinian Corpuscles 2. Meissner’s Corpuscles 3. Root Hair Plexus 4. Free Nerve Endings 5. others B. Temperature (cutaneous & visceral) C. Pain (Nociception) (cutaneous & visceral) D. Proprioception 1. Muscle Spindles 2. Golgi Tendon Organs General Categories of Senses 1. General Senses a. Cutaneous b. Visceral c. Proprioceptive 2. Special Senses48_lol_ns_sensory.docx Bio 48 - Human Physiology IV. The Special Senses A. Smell (Olfaction) B. Taste (Gustation) C. Hearing 1. Structure a. External Ear b. Middle Ear c. Inner Ear 2. Neural Pathways (CN VIII) 3. Mechanism a. Volume b. Tone D. Equilibrium (Balance) 1. Structure 2. Mechanism a. Static (orientation to gravity and linear acceleration) b. Dynamic (orientation to angular acceleration) E. Vision 1. Structure a. Eye (gross anatomy) b. Retina c. Light Path 2. Neural Pathway (CN II) 3. Mechanism of Stimulation of Photoreceptors V. Additional Key Terms / Topics accommodation acuity adaptation baroreceptor concave constriction conversion convex dilation diversion emmetropia frequency hyperopia modality myopia nystagmus phasic presbyopia reflection refraction tonic48_lol_ns_sensory.docx Bio 48 - Human Physiology Study Questions – Sensory Physiology: 1. Define “sensation”and “perception”. 2. Describe the basic structure of a sensory receptor with reference to the neuron. 3. Some receptors have non-neural accessory structures, what is the general purpose of these accessory structures? 4. Describe the five different functional types of receptors and provide examples of each. 5. Define “modality”and “adequate stimulus”. 6. How are different specific stimuli distinguished at the receptor level and at the CNS level? 7. What is necessary for two identical and simultaneous stimuli to be distinguished from each other. 8. Explain how lateral inhibition contributes to stimulus localization. 9. How is the intensity of a stimulus represented in a single neuron? How does the CNS use summation to evaluate stimulus intensity? 10. Describe the characteristics of a “phasic’ receptor. Provide an example. 11. Describe the characteristics of a “tonic’ receptor. Provide an example. 12. Describe how the structure of the pacinian corpuscle contributes to its phasic nature. 13. Describe the distribution and responsiveness of the following receptors: pacinian corpuscle, root hair plexus, Golgi tendon organ and muscle spindle. 14. Describe the structure of the olfactory receptor epithelium. What type of cells function as receptors? What is unique about these cells? 15. Describe the structure of the taste receptor (taste bud). What type of cells function as receptors? 16. Compare and contrast the sensory structures if the inner ear (discuss the bony and membranous labyrinths, receptor epithelium, and overlying gel mass). 17. How is the tone of a sound (soundwave frequency) differentiated at the cochlear level? At the CNS level? 18. How is the volume of a sound (soundwave amplitude) differentiated at the cochlear level? 19. What are the semicircular canals sensitive too? What are the utricle and saccule sensitive too? 20. How is eye movement & stabilization influenced by the vestibular apparatus? 21. Define “nystagmus”. 22. Describe the path of light from its entry into the eye until it stimulates photoreceptors. Name all of the structures the light passes and how they influence the light. 23. Describe how the central retina (i.e. fovea centralis) and the peripheral retina differ both structurally and functionally. 24. Why is the central retina better able to distinguish color and details while the peripheral retina is better able to distinguish weak visual stimuli? 25. Describe the neural pathway from the light receptor cells in the eye to the visual cortex in the brain. Describe the sequence and interconnectivity of the visual pathway neurons as well as the gross characteristics of the visual pathway. 26. Explain how changes in the shape of the lens change the focal point of vision. 27. Explain how color vision works. Example: how can we see yellow if we do not have photoreceptors specifically sensitive to