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86 Cards in this Set
- Front
- Back
free nerve endings
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pain, tickle, itch, temp.
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touch receptors
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encapsulated dendrites, sense pressure and vibration
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special sensory receptors
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vision, taste, hearing, balance
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phasic receptors
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rapidly adapting receptors for smell, pressure, and touch
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tonic receptors
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slowly adapting receptors for body position
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localization
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due to overlapping receptor fields (2 neurons detect 3 locations)
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lateral inhibition
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when an active nerve will inhibit other nerves around it from being stimulated by a stimulus in the receptor field
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meissner's corpuscles
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dendrites in CT, discriminative touch & fine vibration, phasic receptors
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Merkels discs
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free nerve endings, tonic, used in discriminative touch
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ruffini corpuscle
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type II cutaneous mechanoreceptor ---are encapsulated & tonic, feel deep touch, continuous touch, stretch and pressure
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pacinian corpuscle
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onion like- encapsulates, phasic, senses deep pressure, high frequency vibration, diffuse vibration
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cold receptors
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free nerve endings in stratum basale, respond b/t 50-105
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warm receptors
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in dermis respond to temps b/t 90-118 degrees
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bradykinin
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most potent pain stimulus, little adaptation occurs
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nociceptors
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free nerve endings, sense pain. Found everywhere except the brain
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tissue injury releases:
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K+. Kinins, seretonin, histamine, or prostglandins
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fast pain
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not felt in deeper tissues, large A delta fibers
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slow pain
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chronic, in superficial and deeper tissues, smaller C fibers
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superficial somatic pain
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in skin areas
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deep somatic areas
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from muscle, joints, tendons, & fascia
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free nerve endings
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pain, tickle, itch, temp.
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touch receptors
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encapsulated dendrites, sense pressure and vibration
|
|
special sensory receptors
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vision, taste, hearing, balance
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phasic receptors
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rapidly adapting receptors for smell, pressure, and touch
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tonic receptors
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slowly adapting receptors for body position
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localization
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due to overlapping receptor fields (2 neurons detect 3 locations)
|
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lateral inhibition
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when an active nerve will inhibit other nerves around it from being stimulated by a stimulus in the receptor field
|
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meissner's corpuscles
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dendrites in CT, discriminative touch & fine vibration, phasic receptors
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|
Merkels discs
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free nerve endings, tonic, used in discriminative touch
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ruffini corpuscle
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type II cutaneous mechanoreceptor ---are encapsulated & tonic, feel deep touch, continuous touch, stretch and pressure
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pacinian corpuscle
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onion like- encapsulates, phasic, senses deep pressure, high frequency vibration, diffuse vibration
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cold receptors
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free nerve endings in stratum basale, respond b/t 50-105
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warm receptors
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in dermis respond to temps b/t 90-118 degrees
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bradykinin
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most potent pain stimulus, little adaptation occurs
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nociceptors
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free nerve endings, sense pain. Found everywhere except the brain
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tissue injury releases:
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K+. Kinins, seretonin, histamine, or prostglandins
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fast pain
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not felt in deeper tissues, large A delta fibers
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slow pain
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chronic, in superficial and deeper tissues, smaller C fibers
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superficial somatic pain
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in skin areas
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deep somatic areas
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from muscle, joints, tendons, & fascia
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visceral pain
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organ pain---cutting causes no pain but distension can cause severe pain
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referred pain
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felt in skin area overlying an organ or an area far away but has common innervation
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aspirin and ibuprofen
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block formation of prostaglandins
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novocaine
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blocks conduction of nerve impulses along pain fibers
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morphine
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lessen the perception of pain
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enkephalins
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endogenous analgesic= 200 x more potent than morphine
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gate control theory
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theory that as long as there is balance b/t large and small fibers there will be continuous inhibtion of pain fibers
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descending pathway mechanism of gate control
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desceding interneurons from the cortex, reach the medulla and secrete enkephalins and synapse on 2nd order neurons thus inhibiting them
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Muscle spindles
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innervated by gamma motor neurons
are intrafusal muscle fibers leads to muscle contraction |
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golgi tendon organs
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at junction of tendon and muscle
when tendon is overly stretched it leads to relaxation |
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ruffini corpuscles in joints
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found in the joint capsule and responds to pressure
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pacinian corpuscles
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in CR around the joint
responds to acceleration and deceleration of the joint |
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first order neurons (somatic sensory)
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conducts impulses to brainstem or cord
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second order neurons (somatic sensory)
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impulses from cord or brainstem to thalamus and decussates before reaching the thalamus
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dorsal columns- medial lemniscal system
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for fine touch, stereognosis, proprioception, kinesthesia
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stereognosis
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ability to recognize size, shape, texture
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proprioception
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awareness of precise body position and weight discrimination
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kinesthesia
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awareness of direction of movement
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spinothalamic/anterolateral system
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carries crude senses
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senses carried by spinothalamic/anterolateral system
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pain
thermal sensation crude touch and pressure itch and tickle sexual sensations |
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spinocerebellar (anterior and posterior)
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proprioception
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pathway of dorsal column/medial lemniscus
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1. into DRG go to medulla and decussate
2. becomes medial lemniscus and goes to the thalamus 3. synapses in the thalamus and goes to the cortex ---sensory area 1 (postcentral gyrus) |
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1st order neuron in medial lemniscus pathway
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goes up cord, synapses in medulla
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2nd order neuron in medial lemniscus pathway
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synapses in medulla and decussates, goes to the thalamus
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3rd order neuron in medial lemniscus pathway
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synapses in thalamus and goes to the cortex (sensory area 1) in the postcentral gyrus
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senses carried by spinothalamic pathway
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pain, temp. crude touch, itch, tickle, sexual sensations
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spinothalamic tract pathway
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1st order neuron: synapses in Dorsal Horn
2nd order neuron: decussates in anterior commissure-->opposite & anterior lateral white columns and ascend 3rd order neurons: synapses in thalamus and goes to cerebral cortex |
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anterior spinothalamic tract
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carries itch, tickle, pressure, vibrations, crude touch
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spinocerebellar tract
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major route of proprioception, impulses go from limbs straight to inferior cerebellar peduncle on same side
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basal ganglia
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establishes muscle tone, & integrate semivoluntary automatic movements
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direct pathways
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from cerebral cortex-->cord -->muscles
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indirect pathways
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cortex-->basal ganglia--> thalamus-->reticular formation-->cerebellum-->cord-->muscles
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primary motor area
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in precentral gyrus of frontal lobe
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direct pathways (pyramidal tracts)
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corticospinal
corticobulbar used for precise muscular movement |
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lateral corticospinal tract
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skilled movements (hands and feet)
90% decussation of axons in medulla |
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anterior corticospinal tract
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control neck and trunk muscles
10% of axons decussate in the cord |
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corticubulbar tracts
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to nuclei of CN 3, 4,5,6,7,9,10,11,12)
moves eyes, tongue, chewing, expressions and speech |
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indirect tracts are
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rubrospinal
tectospinal vestibulospinal lateral reticulospinal medial reticulospinal |
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rubrospinal tract
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cortex-->red nucleus--> contralateral skeletal muscles
governs precise movements in distal parts of limbs |
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tectospinal tract
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cortex-->superior colliculus-->contralateral skeletal muscle that move head and eyes
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vestibulospinal tract
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cortex-->vestibular nucleus-->stabilizer muscles
maintains balance in response to head movements |
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lateral reticulospinal tract
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cortex--> reticular formation-->flexor muscles (inhibits extensors)
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medial reticulospinal tract
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cortex-->reticular formation--> extensor muscles (inhibits flexors)
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role of basal ganglia
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initiates and terminate movements
suppresses unwanted movements |
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damage to basal ganglia results in:
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uncontrolled body movements, rigidity and tremors
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cerebellar functions
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learning and performing rapid coordinated movements, highly skilled movements, posture and equilibrium
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