Lecture4 Flashcards
what is saturation
absolute refractory period…no APs can be fired
3 ways of representing information
place coding
frequency coding
recruitment
space between saturation and threshold is known as
dynamic range
what does dc/ml respond to
touch
vibration
proprioception
what does anterolateral respond to
pain and temperature
axons that terminate in the VPL thalamus have cell bodies in the _____ nuclei
cuneate or gracile
axons for DC/ML system are coming from
body and poster 1/3 of head
mechanoreceptors for lower part of body are in the ___ spinal cord
lumbar
mechanoreceptors for upper part of body are in the ___ spinal cord
cervical
DC/ML
1st order
2nd order
3rd order
1: DRG
2: cuneate or gracile nuclei
3: VPL
Trigeminal
1st order
2nd order
3rd order
1: trigemina ganglion
2: ipsilateral principal trigeminal nucleus
3: VPM
Ad fibers main projection?
marginal zone (laminae 1) also some laminae 5 projections
C fibers main projection
substantia gelatinosa (laminae 2)
also some laminae 1 projection
will go to thalamus, midbrain, or reticular formation
cell bodies of Ad fibers are in?
DRG
cell bodies of C fibers are in?
DRG
laminae 1 nuerons form which pathway?
neospinothalamic
when does windup happen
in response to activation of tonic receptors of nociceptive afferents
why does windup happen
response won’t outlast stimulus BUT will fire rapidly to get a stronger signal (so you can feel the stimulus and stop it if it causing you pain)
where does primary hyperalgesia occur
tissues
where does secondary hyperalgesia occur
spinal cord
VPL is sensory for the
body
VPM is sensory for the
face
fn of intralaminar nuclei
alterness
arousal
pain
VPL gets input form
body and 1/3 of face
VPM gets input from
trigeminal system
VP thalamus projects to
SI- primary somatic somatosensory cortex
where is the first site for bilateral input
SII- secondary somatic somatosensory cortex
SII projects to
limbic system (amygdala and hippocampus): learning + memory
motor cortex
auditory and visual association areas
back to SI
Types of receptors in the major sensory systems
mechanoreceptors
nociceptors and thermoreceptors
proprioceptors
which receptors have free nerve endings
nociceptors
thermoreceptors
which receptors have encapsulated nerve endings
mechanoreceptors
- messiness corpuscles
- merkles disk
- pacinian corpuscles
- ruffian endings
fn of meissners corpuscles
respond well to light touch and light movement of skin
fn of merkels disk
respond well to touch and pressure
fn of pacinian corpuscles
respond well to vibrations
fn of ruffian endings
respond well to stretching of muscles
three types of proprioceptive mechanoreceptors
muscle spindles
golgi tendon organs
joint receptors
fn of muscle spindles
respond well to stretch, length, and rate of change
fn of GTO
in tendons, respond well to force of muscle length
two types of adaptation
phasic
tonic
