somatic sensation
somatesthetic
proprioceptive
special senses
vision
hearing
taste
smell
uses of sensory input
control of efferent output
reticular formation and cortical arousal and consciousness
stored for future reference
perception: the conscious interpretion of the external world
limited receptor modalities
differential processing of input
manipulation of input to produce altered “reality”
receptors have differential sensitivities to various stimuli
stimulus modality
transduction
adequate stimulus and the law of specific nerve energies
receptor types
photoreceptors
mechanoreceptors
thermoreceptors
chemoreceptors
nociceptors
compound sensations: wetness
altered membrane permeability of receptors results in graded receptor potential
causes
mechanical stimulation
chemical signals
temperature
electromagnetic radiation
increased intensity of stimulus results in increased receptor potential
increased receptor potential results in increased frequency of action potentials [Why?]
frequency code [number of action potentials]
population code [number of activated receptors]
adaptation
tonic receptors
proprioceptors
nociceptors
phasic receptors
off response
somatosensory pathways
destinies of afferent information
reflex arc
ascending pathway
labeled lines
decoding the stimulus
stimulus modality
receptor type
ascending pathway
stimulus location
location of activated receptor field
pathway to somatesthetic cortex
stimulus intensity
frequency of action potentials
number of activated receptors
activation of sensory pathway
phantom pain
acuity is influenced by receptor field size
somatesthetic cortical homunculus
protective mechanism
motivated behavioral responses
emotional responses
subjective interpretation
categories of pain receptors
mechanical nociceptors
thermal nociceptors
polymodal nociceptors
free nerve endings
sensitization by prostaglandins
pathways
fast pain pathway
myelinated A-delta fibers
slow pain pathway
unmyelinated C fibers
role of bradykinin
capsaicin
synapse with second-order neuron
substance P
activates ascending pathways
somatosensory cortex
thalamus
reticular formation
roles of hypothalamus and limbic system
glutamate
AMPAa receptors
generate action potentials in dorsal horn cells
transmission of pain message to higher centers
NMDAb receptors
Ca2+ entry into dorsal horn cells
induces hyperexcitability
analgesia
periaqueductal gray matter and reticular formation
descending analgesic system
blocking substance P release from afferent synaptic terminal
opiate receptors for endorphins, enkephalins, and dynorphin
|
[ Previous lecture ][
Anatomy & Physiology 2 syllabus ][
Next lecture ] [ Page created 29 July 1999 ][ Last update 22 January 2004 ] [ Questions about this lecture? E-mail me ] |