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39 Cards in this Set
- Front
- Back
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mechanoreceptors |
-the basis ofsensations like touch, pressure, vibration, muscle and joint position(proprioception), hearing and balance -Pacinian corpuscles,Ruffini corpuscles, Merkel disks, and Meissner corpuscles. Bending, stretchingor deforming stimulates a mechanoreceptor |
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Thermoreceptors |
-sensitive to changes in temperature |
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Nociceptors |
-sense pain from harmful stimuli -respond to extreme mechanical and temperature stimuli as well as to products of tissue damage |
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electromagnetic receptors |
aka photoreceptors -detect light striking the retinas |
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chemoreceptors |
-detect chemicals in the mouth, nose and body fluids to produce sensations of taste and smell, and detection of CO2, O2, H+, and osmolality |
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labeled line principle |
The concept of specificity in sensory nerve fibers that transmit only one modality of sensation |
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receptors |
-can also be called transducers because they convert a stimulus into an electrical signal |
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generator/receptor potentials |
-stimulation of receptors causes a change in the membrane potential of that receptor -graded response |
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transmission |
generator potentials resulting in AP going to the CNS |
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adaptation |
in the face of a continuous stimulus, AP frequency may quickly or gradually change depending on the type of receptor -EX: cant feel the touch of wedding ring |
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Tonic receptors |
slowly adapting -keep CNS up to date on info coming from periph -baroreceptors, muscle spindles, pain |
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Phasic receptors |
quickly adapting -sends CNS information on stimulus -touch and vibration- meissner and pacinian corpuscle |
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Labelled line coding |
a given pathway between a receptor and its destination is the cortex only transmits action potential from one spot and for one modailty |
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Webers law |
describes the ratio of an added stunmulus to a stimulus that is already in place -a stimulus has to overcome a background signal before it can be noticed |
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high two point discrimination |
have greater representation in the cortex |
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myelinated spinal neurons |
-high conducting velocity -alpha beta delta gamma -mechanoreceptors, motor neurons, fast pain |
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myelinated medium sized neurons |
-medium conducting velocity -associated with autonomic pathways |
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small unmyelinated neurons |
-low conducting velocity -associated with pain, itch, temp, and crude touch pathways |
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meissner's corpuscles |
return via A betas |
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free nerve endings |
-some return via A deltas -some return via C (itch pain and tickle) |
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spinal nerves |
mixed nerves, carry both sensory and motor information |
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somatic sensory information |
returns to spinal cord via dorsal root |
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dermatome |
area of skin innervated by a single dorsal root |
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Dorsal column-leminiscal and anterolateral system/spinothalamic tract |
somatic sensory information from the trunk and the limbs are transmitted to CNS via 1 2 |
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dorsal column-leminiscal modalities |
fine touch, vibration, position, mechanoreceptors |
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anterolateral system/spinothalamic tract modalities |
pain and temp, crude touch, pressure, tickling, itching, sexual sensations |
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labeled line theory |
location of stimulus interpreted by brain according to pathway and destination in sensory cortex |
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hyperesthesia |
-exaggerated and unpleasant sensations -can be caused by lesions of thalamus or surgical albation |
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analgesia |
inability to feel pain |
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hyperalgesia |
exaggerated pain response |
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allodynia |
painful perception of non noxious stimulus |
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causalgia |
burning pain because of nerve damage |
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absolute sensory theshold |
lowest intensity stimulus that can be detected in 50% of trials |
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first order neuron |
transmits AP from the skin and muscles to the CNS |
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second order neurons |
cross on the midline and transmit AP to the thalamus |
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third order neuron |
project to the parietal lobe. sensory information from the left side of the body goes to the right side of the brain |
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stereognosis |
ability to perceive and recognize the form of an object in the absence of visual and auditory information |
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neuropathic pain |
no tissue damage, synaptic changes |
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TRP channels (transient receptor channels) |
part chemoreceptor par mechanoreceptor -camphor depolarizes warmth receptors, menthol depolarizes cold receptors |
