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66 Cards in this Set
- Front
- Back
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depolarization |
membrane potential more positive than resting |
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repolarization |
return of membrane potential to resting value |
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hyperpolorization |
resting potential more negative than resting |
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threshold |
requisite potential for AP to occur |
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what are axons of some neurons wrapped in? |
myelin sheaths |
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function of myelin? |
prevents current from leaking across membrane |
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AP jumps from one_____ to the next |
Node of ranvier |
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Saltatory Conduction |
speeds up conduction velocity -insulation of myelin sheaths |
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information flows from presynaptic cell to post synaptic List the steps: |
-ap down axon -axon terminals depolarize -Neurotransmitter released -Change in membrane voltage of postsynaptic cell -if excitatory then postsynaptic more likely to fire |
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sensory neurons |
Detect changes in the environment referred to as stimuli and transmit information to CNS |
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Where to afferent neurons transmit information to? and where do afferent axons enter spinal chord? |
-CNS -Dorsal roots |
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Motor nuerons |
send signals to target tissue in order to elicit a response to a particular stiumulus |
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Efferent information transmits information where? Where does it leave spinal chord? |
-Away from CNS -Ventral roots |
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interneurons -how many of neurons are inter? |
-serve a integrative function-interconnect incoming sensory and outgoing motor info -90% |
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motor pool |
all the motor neurons that innervate a particular muscle, the cell bodies of all the motor neurons in a motor pool are clustered together in spinal chord |
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innervation ratio |
number of muscle fibers innervated by a motor neuron |
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a motor nuerons |
innervate extrafusal muscle fibers that are responsible for generating force |
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y motor nuerons |
innervate intrafusal muscle fibers in muscle spindle |
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motor unit |
motor nueron and the group of muscle fibers it innervates |
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smallest functional unit that nervous system can use to control movement |
motor unit |
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zero firing rate: Minimum firing rate: Maximum firing rate: |
-bellow threshold -at threshold -high forces |
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EMG |
records and quantify electrical activity of activated motor units in the muscle fiber |
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Primary sensory affarent |
a neuron that carries sensory information from periphery to CNS |
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somatosensory system includes: |
-cutaneous sensation -proprioception |
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vestibular system |
detects static head position, angular acceleration of head, linear acceleration of head |
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vision |
uses light to detect location movement and properties of objects in environment, parts of our own bodies and our movement relative to environment |
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adequate stiumulus |
unique stimulus that activates a specific receptor at low energy level. Stimulus that naturally activates receptor |
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modality |
general class of stimulus, determined by the type of energy transmitted by the stimulus and receptors specialized to sense that energy |
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adaptation |
decrease in firing rate of a sensory neuron in response to a constant stimulus |
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receptive field |
region of sensory surface that when stimulated modulates the activity of a neuron |
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intensity coding |
receptors can detect and code strength or magnitude of stimulus |
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graded response |
greater the stimulus the greater the response |
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spacial summation |
larger number of receptors that are stimulated, the stronger the percieved stimulus |
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temporal summation |
a strong stimulus caused receptors to fire at a higher frequency than weak ones |
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encapsulated endings |
primarily mechanoreceptors that inform about object movement and frictions |
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free endings primarily act as |
nociceptors |
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nociceptors |
sensory nerve cell that responds to potentially damaging stimuli by sending signals to spinal chord Free: sensitive ends encapsulated: pressure |
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cutaneous receptors can be classified as either 1. 2. |
-fast adapting (dynamic sensitivity -slowly adapting (static) |
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do primary afferents transmit sensory information directly to cortex? |
no- at each synapse there is oppurtunity for info to be enhanced, inhibited, integrated |
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stretch reflex |
muscle spindles detect stretch and muscle spindle afferents increase firing rate |
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in spinal chord muscle spindle afferents Excite: Inhibit: |
-alpha motor neurons innervating stretched muscle -inhibit via an interneuron the alpha motor neurons of antagonistic muscle |
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where are golgi tendon organs located |
myotendinous junction |
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proprioceptive information travels to |
primary somatosensory cortex and cerebellum |
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Deafferented individuals |
df |
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vestibular system |
detect position and acceleration of head |
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hair cells |
-membrane voltage becomes more or less negative depending on direction of bending -synapse on vestibular primary afferents that send information to CNS |
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semiciricular canals Mechanism: inertia of endolymph |
detect angular acceleration of head -can detect rotation about any axis |
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rate coding |
primary afferents fire spontaneously when head at rest |
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what happens when there is angular acceleration to the right |
-afferent fibers from right horizontal canal increase firing rates -from left decrease firing rates |
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primary afferent firing rates code both ____ and ____ of acceleration |
amount and direction of acceleration |
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otoliths uricle and scales: |
detect linear acceleration and static tilt of head Mechanism: higher specific weight than endolymph |
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vestibulocochlear nerve transmits vestibular information to ______ |
vestibular nuclei in brainstem |
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vestibulo occular reflex |
if head movies while person is fixated on an object vestibular information is used to rotate eyes in order to maintain fixation |
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rods |
-very sensitive -resonpsinble for detecting movement and contrast |
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cones |
-need strong light -detect color -detect fine features |
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visual information from photoreceptors not transmitted directly out of retina: |
2 synapses between photoreceptors and ganglion cells whose axons leave retire via optic nerve |
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axons of ganglion cells synapse directly on cells in_____ these cells send visual information to ____ located in the _____ |
thalmus, primary visual cortex, occipital lobe |
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ventral pathway |
-from visual cortex to temporal love -responsible for object recognition |
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dorsal pathay |
-visual cortex to parietal love -responsible for object location and movement |
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binocular cue |
disparity of images received by left and right eyes |
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-interposition -relative size -shadows -linear perspective -motion parallex |
-object blocking part of another object is nearer -object of smaller sizes at varying distances cast different retinal image sizes -3 dimensional form and source of light -parallel lines converge towards vanishing point -image of nearly objects cross retire more quickly - |
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deaffereneted patient is an individual who has damage in the |
motor cortex |
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semicircular canals detect |
angular motion |
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utricle and scales detect |
linear motion |
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patients with damage to inferior temporal area are unable to_____but could___ |
recognize objects but could reach out and grasp them |
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spatial summation implies that |
larger number of receptors that are stimulated the stronger the perceived stimulus |
