Chapter 15 [ EXAM #2 ] Flashcards
where does visceral sensory info go
primary reflex centers
brainstem and diencephalon
where does somatic sensory info go
primary somatosensory cortex
cerebellum
what are two sub-divisions of motor NS
somatic and autonomic
what are two sub-divisions of autonomic NS
sympathetic and parasympathetic
difference between general and special senses
general = touch, pressure, temp, pain, proprioception
special = smell, taste, vision, hearing, balance
what is transduction
converting stimulus into action potentials sent to CNS
what are sensory receptors
specialized cell or dendrites of sensory neuron
what percentage of info that moves through ascending tract reaches our consciousness
1 %
what is sensor specificity
detection of different stimuli (e.g. chemical vs touch)
what is receptive field
area of body monitored by a single receptor cell
difference between large and small receptive fields
large = poor ability to localize stimulus
small = finer ability to localize stimulus
sensory receptor types
thermoreceptors = temperature
nociceptors = pain
chemoreceptors = chemicals
mechanoreceptors = physical distortion
tactile receptors = touch
baroreceptors = stretch / pressure
proprioceptors = joint position
are there more or less pain, temp, and touch receptors in viscera
less pain, tamp, and touch receptors in viscera
proprioceptors: more in viscera or somatic NS
none in viscera
only in somatic NS
function: chemoreceptors
detect change in chemical concentration
location and function: central chemoreceptors
respiratory centers of brain
detects pH and CO2
location and function: peripheral chemoreceptors
carotid bodies and aortic bodies
detects pH, CO2, and O2 in blood
are nociceptors present in the brain?
no
are nociceptors present in the meninges?
yes (headache)
location: nociceptors
skin, mucous membranes, organs, bones
description: nociceptors
free nerve endings with large receptive fields
description: type A pain fibers
stabbing sharp localized pain
myelinated
fast and short-lived
description: type C pain fibers
dull aching
unmyelinated
slow and long-lived
difference: somatic vs. visceral pain
somatic = skin, muscles, joints
visceral = organs
what is referred pain
pain felt in a dermatome far from affected organ
e.g. heart attack
two NTs that relay pain
substance P
glutamate
two Endogenous opiods
endorphins = runner high
enkephalins = birth
what is anesthesia
loss of sensation, targets synapses
classification of first order sensory neruon
unipolar sensory neuron
classification of second order neuron
interneuron
classification of third order neruon
interneuron
location: first order neuron
DRG or cranial nerve ganglion
location: second order neuron
dorsal horn or brain stem
location: third order neuron
thalamus
function: first order neuron
delivers somatic sensory sensations to CNS
function: second order neuron
decussates impulse
function: third order neuron
conducts impulse to primary somatosensory cortex
what are three somatic sensory pathways
posterior column pathway
spinocerebellar pathway
spinothalamic pathway
process: posterior column pathway
[ carries precisely localized sensory info ]
1st order neuron
2nd order neuron
decussates in medulla
synapse onto 3rd order neuron
sort / filter arriving stimuli
synapse to thalamus
sends to primary somatosensory cortex
process: spinothalamic pathway
[ impulses for poorly localized sensory info ]
1st order = connects receptor to 2nd order
2nd order = decussation through brain stem
3rd order = synapse to thalamus
what is phantom limb pain
sensory neuron bodies remain after amputation
pain is felt in limb that is not there
process: spinocerebellar pathway
[ critical for posture, balance, movement ]
proprioception info arrives at cerebellum
1st order = synapse on 2nd order in dorsal gray horn
2nd order = interneuron axons ascend through tacts
synapses on Purkinje cells in cerebellum
what type of receptors are in the visceral sensory pathway
interoreceptors
how many neurons are needed in the somatic NS
two motor neurons
location: upper motor neuron
precentral cortex
location: lower motor neuron
brainstem / ventral horn
lower motor neuron innervates ___ ____ ____
lower motor neuron innervates one motor unit
what is a motor unit
mew to many muscle fibers being controlled by one neuron
corticospinal pathway controls…
skeletal muscle
medial pathway controls…
gross movement of trunk and proximal limbs
lateral pathway controls…
distal limb movement (precise)
