Test 2 - Lecture 1 (sensory reception) Flashcards
photoreceptors
vision
chemoreceptors
smell/taste
mechanoreceptors
touch
nociceptors
pain
“the state of” implies current conditions…
both within and outside the body
peripheral
outside the CNS
stimulus
physical energy to which a particular sensory receptor will respond
transduction
neurochemical process through which a sensory neuron transforms the stimulus energy into a bioelectrical signal
bioelectrical signal
action potentials that originate from a sensory neuron
mechanical receptors stimulated by
pressure/sound
electromagnetic receptors stimulated by
radiant heat; light (retna)
thermal receptors stimulated by
heat
chemical receptors stimulated by
aciditiy; concentration
modality
type of stimulus
intensity
strength of stimulus
duration
span of time that stimulus is sensed
location
of the receptor upon or within the body, and/or the origin of the stimulus from outside the body
sensory receptor: sensory neuron
directly transduces the stimulus energy
gives rise to an axon that serves as the primary sensory afferent fiber from that receptor
sensory receptor: modified epithelial cell
receives the stimulus energy
accessory structures to a sensory receptor
enhance or focus a particular stimulus upon the receptor
sensory receptors transduce the “ “ into a coded ___________ for relay in the CNS
stimulus energy; bioelectrical signal
stimulus transduction starts with a
generator potential
generator potential
responsive depolarization of the sensory neuron’s membrane
the greater a stimulus intensity is…
the greater the membrane change is
the greater the stimulus intensity is…
the greater the depolarization of sensory neuron is
stimulus threshold
how strong stimulus intensity is action upon a receptor
the greater the stimulus intensity is above threshold…
the greater the depolarization and frequency is
the frequency of action potentials encodes
stimulus intensity
the duration of the train of action potentials encodes
stimulus duration
recepter “adaptation”
declining generator response during a sustained stimulus
slowly adapting sensory receptors
gradually decreasing frequency for the duration that the stimulus is applied
(stimulus intensity is changing, but not while it is sustained)
rapidly adapting sensory receptors
rapid fall in the frequency of action potentials, or else a complete cessation of action potentials for the remainder of the stimulus duration
(sustained signaling as long as the stimulus is sustained, with a gradual reduction in the frequency)
peripheral sensory information are…
primary afferent axons and synapse in the dorsal horn of the spinal cord
first order neuron
sensory receptor neuron in the periphery that transduces the stimulus energy into a train of action potentials
(axon is a primary sensory afferent fiber)
second order relay neuron
located in the dorsal horn of the spinal cord
(projects a secondary fiber via an ascending tract through the spinal cord and brainstem
third order relay neuron
located within the thalamus
projects a tertiary fiber into the primary sensory cortex of the brain
the distribution of peripheral sensory receptors presents as being
topographically organized
topographically organized
spatial arrangement of the primary afferent fibers “maps” the spatial arrangement of the receptive fields
somatotopic mapping
is maintained from specific body regions through the ascending tracts of fibers into specific regions of the sensory cortex so as to preserve identification of the location of peripheral sensory information
two major ascending tracts serve to relay peripheral sensory information into the somatosensory areas of the cerebral cortex
dorsal column
anterolateral (ventrolateral) system
