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58 Cards in this Set
- Front
- Back
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Vision sensory modality carried by CN |
CN II |
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Olfaction sensory modality carried by CN |
CN I |
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Taste sensory modality carried by CN |
CN VII and CN IX |
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Hearing and balance (equilibrium) sensory modality carried by CN |
CN VIII
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General or Somatic senses (somatosensory) detected from all parts of the body + head and transmitted to CNS via |
CN V
spinal nerves except CI |
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2 types of Mechanoreceptors |
- exteroceptors – respond to stimuli from outsidethe body eg. touch receptors - - proprioceptors – give information about positionof the body, or its parts eg. muscle spindles |
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The generator potential (GP) is a ________ of the peripheral, receptiveportion of the sensory axon |
depolarization except: in rods and cones --> GP is hyperpolarization |
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GP is similar to EPSP --> (3) |
- graded in amplitude (eg. the bigger the stimulus, the biggerthe GP)
- does NOT cause the membrane to be refractory (causes opening of channel) - is NOT actively propagated. |
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Action potential (3) |
- all or none (magnitude)
- cause membrane to become refractory - are actively propagated by regenerating themselves along the axonal membrane |
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The GP of somatosensory mechanoreceptors |
–direct effect of mechanical stimuli onstretch-sensitive channels. •Non-selectiveand allow both Na+and K+to pass. •Netresult is depolarization due to greater driving force for Na+. |
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The GP of nociceptors, photoreceptors, andchemoreceptors |
– G-protein–coupled mechanisms that influence channels indirectly. |
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How is stimulus intensity coded? |
- frequency coding - population coding |
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Frequency coding |
- greater intensity --> greater frequency of AP in indv. axons - not linear function (ie. touch not related to amount of receptors) |
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Refractory period and frequency of AP |
Refractory period sets limit on the frequency of AP |
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Population coding |
- w/ increased intensity, more indv receptors are recruited |
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Slowly adapting [sensory receptor] *read more in notes |
- monitor static unchanging stimulus - tonic |
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Rapidly adapting [sensory receptor] *read more in notes |
- detect onset of stimulus - phasic |
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Rapidly adapting convey info ____ |
on rapid changes in stimulus INTENSITY and RATE |
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Rapidly adapting doesn't provide info on ____ |
duration of stimulus |
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Slowly adapting provides info on _____ |
duration of stimulus |
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examples of slowly adapting sensory receptors |
- ruffini endings - merkel's endings - secondary muscle spindle endings - pain receptors - joint capsule |
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examples of rapidly adapting sensory receptors |
- pacinian corpuscle - meissner corpuscle - endings surrounding hair follicles - primary muscle spindle endings |
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adaptation in mechanoreceptors is due to ________ surrounding the axon terminal. |
accessory (non-neuronal) structures |
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–Meissner’scorps. are abundant in |
fingertips |
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Place rapidly adapting sensory receptor on body parts we need to |
sense - eg. pacinian corpuscles on fingers |
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•Merkel’s endings and Ruffini endings signal |
maintained pressure |
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example Proprioception sensory receptors |
- muscle spindles - golgi tendon organs - joint receptors - skin receptors |
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•Joint receptors |
–Ruffiniendings and Paciniancorpuscles –injoint capsules and ligaments |
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•Skin receptors |
–deformedby changes in joint angle |
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•Golgi Tendon Organs |
–tensionreceptors |
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Primary muscle spindle signal |
rate of change of muscle length |
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Secondary muscle spindle signal |
absolute length |
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Pain and Temperature detected by receptors |
which are free nerve endings - no associated capsule orspecialization. (increase firing when warm) |
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2 ways to classify peripheral nerves |
- conduction velocity (ABC) - diameter (I, II, III, IV) |
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classification of peripheral nerves via diameter (I, II, III, IV) is exclusive to |
sensory axons |
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Group A |
- fastest conduction velocity - large diameter, thick myelin |
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Group B |
- smaller than group A, but still myelinated |
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Group C |
- smallest diameter, non-myelinated |
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Type of sensory info group C carries |
- dull aching pain - temp - touch, pressure, itch |
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Ia innervates |
primary muscle spinding ending |
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*spinal cord* grey matter consists of |
neuronal cell bodies dendrites, synapses no myelin |
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*spinal cord* white matter divided into |
dorsal, lateral, ventral columns |
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*spinal cord* white matter contains |
axons |
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Dorsal root carries ___ |
sensory info into spinal cord |
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Sensory neuron's cell bodies are in |
DRG |
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Ventral root contains |
axons of motor neurons |
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Sensory neuron's cell bodies are in |
ventral horn gray matter |
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Intermediolateralhorn at spinal levels |
- T. 1 – L. 2 and S. 2 – S.4 – containscell bodies of preganglionic autonomic neurones |
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Dorsal horn contains |
sensory neurons |
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study this pic |
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reflex |
occurs automatically: - it does notrequire a voluntary command from the brain - It requires activity in a series of neuronsreferred to as a reflex arc |
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components of a reflex arc are |
•A sensory receptor •A sensory axon •An integration centre in the CNS •A motor neurone and its motor axon •An effector organ eg.muscle or gland |
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1a |
rapidly adapting |
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Muscle spindle |
- detects stretch of muscle |
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2 types of intrafusal muscle fibers |
– nuclear bag fibres (usually only one per spindle) – nuclear chain fibres (several per spindle). |
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Exrafusal fiber |
- contain contractile elements |
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Intrafusal fiber |
- noncontractile central portion - contractile portion at ends |
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*study sensory innervation + monosynaptic stretch reflex + polysynaptic flexor + cross extensory reflex* |
go |
