Exam #1 Review Topics Lesson 1: What is the difference between the afferent division and the efferent division of the nervous system? Which involves the sensory pathway? Which involves the motor pathway? What are their components? Afferent: Sensory pathway. Receptors detect stimuli. Deliver sensory info TO CNS. Passes info to CNS in form of action potential.Efferent: Motor pathway. Nuclei. Motor tracts and nerves (carries commands to muscles and glands)• Sensory pathways: Nerves- axon bundles in PNS. Tracts- axon bundles in CNS. Nuclei- cell bodes located in CNS.What are the 6 general senses?Temperature, pain, touch, pressure, vibration, proprioceptionWhat are the 5 special senses?Olfaction (smell), vision (sight), gustation (taste), equilibrium (balance), hearingWhy is receptor specificity important to the detection of a specific stimulus?Because each receptor has a characteristic sensitivity. (ex. Your hands don’t smell or taste, and your eyes don’t hear, ect.)What does that have to do with labeled lines in the nervous system? Arriving stimulus reaches cortical neurons via labeled line (link between receptor and cortical neuron). Each labeled line carries info about ONE form such as force, dissolved chemical, sound, or light. What is the difference between sensation and perception?Sensation is the arriving information from general senses. Perception is conscious awareness of a sensation. If a receptor has a large receptive field, is it easier or harder to localize the stimulus? What if the receptor has a small receptive field?The larger the receptive field, the more difficult it is to localize a stimulus. What is adaptation and how are tonic and phasic receptors involved? Adaptation is reduction in sensitivity of a constant stimulus. The nervous system quickly adapts to stimuli that are painless and constant(new smells, rings, earrings.) Tonic receptors: always active, show little peripheral adaptation, are slow-adapting receptors. Ex: pain receptor (nociceptors) remind you of an injury long after the initial damage occurred. Phasic receptors: normally inactive, become active for short time when change occurs, fast- acting, provide info about intensity and rate of change of stimulus. Ex: thermoreceptors detect rapid change in temp.*Your perception of the nature of the stimulus depends on the path it takes inside the CNS.What is the difference between central adaptation and peripheral adaptation? What are the four types of general sensory receptors? 1. Nociceptors (pain receptors). 2. Thermoreceptors (temperature receptors). 3. Mechanoreceptors (physical distortion). 4. Chemoreceptors (chemical concentration.) What is the difference between the pain information sent by type A fibers and type C fibers?Type A fibers carry sensation of fast pain, or prickling pain. Type C carries sensations of slow pain. Type C causes a generalized activation of the reticular formation and thalamus. How many different classes of mechanoreceptors are there? 1.Tactile receptors - provide the sensations of touch, pressure, and vibration2.Baroreceptors- detects pressure changes in the walls of blood vessels and in portions of the digestive, reproductive, and urinary tracts. 3. Proprioceptors- monitor positions of joints and muscles. (help us feel body in 3d). The most structurally and functionally complex of general sensory receptors. Of the tactile receptors, how many types are there? Can you name the different types of stimuli that each type detects? 6 types.1. Free nerve endings- detects touch and pressure2. Root hair plexus nerve endings- detect initial contact and subsequent movements. 3. Tactile discs- aka merkel discs. Fine touch and pressure receptors. Small receptive field4. Tactile corpuscles- aka meissners corpuscles. Perceive sensations of fine touch, pressure, and low- frequency vibration. Adapt to stimuli 1 sec after contact.5. Lamellated corpuscles- aka pacinian corpuscles. Sensitive to deep pressure. Fast acting receptors. Most sensitive to pulsing or high-frequency vibrating stimuli.6. Ruffini corpuscles- sensitive to pressure and distortion of skin. Where can you find baroreceptors, proprioceptors, and chemoreceptors? Baroreceptors- found in free nerve endings that branch within elastic tissues; in wall of distensible organ(ex. Blood vessel)Proprioceptor- found in muscle spindles, golgi tendon organs, receptors in joint capsulesChemoreceptors- carotid bodies (near the origin of the internal carotid arteries oneach side of the neck), and Aortic bodies (between the major branches of the aortic arch)What are the three major somatic sensory pathways that carry sensory information to upper CNS centers? What kind of information does each pathway carry?1.The Spinothalamic pathway - conscious sensation of poorly localized “crude” touch, pressure, pain, and temp (from spinal cord to thalamus)2.The Spinocerebellar pathway - cerebellum receives proprioceptive info of skeletal muscles, tendons and joints. 3.The posterior column pathway - sensation of highly localized “fine” touch, pressure, vibration, and proprioception How are these sensory pathways involved in referred pain? Sensations arriving at segment of spinal cord can stimulate interneurons that are part of the spinothalamic pathway. Activity in interneurons leads to stimulation of primary sensory cortex, so you can feel pain in specific part of body surface. Referred pain ex: heart attack pain is felt in the left arm. Appendicitis is felt first in area around the navel and then in the right, lower quadrant. What is the difference between spastic and flaccid paralysis? What causes these types of paralysis? Spastic- caused by damage to upper motor neuronsFlaccid- damage to lower motor neuronsWhat is amyotrophic lateral sclerosis? How does it affect the nervous and muscular systems? It is progressive degenerative disorder affecting motor neurons in the spinal cord, brain stem, and cerebral hemisphere. Death of these neurons cause atrophy in associated skeletal muscles. Lesson 2: What are the cells involved in olfaction and gustation? Chemoreceptors are involved in both.How do olfactory receptor cells detect different odors? Olfactory receptors are highly modified neurons. Olfactory reception involves detecting dissolved chemicals as they interact with odorant-binding proteins on cell membranes of olfactory receptor cells. CNS interprets smells by the pattern of receptor activity. How do
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