Chapter 5: sensorimotor system Flashcards
receptor cell
sense form of energy or substance, internal or external, than converts into a change in the electrical potentials across its membrane(acts as a filter)
labeled lines
particular neurons that are labeled for distinctive sensory experiences
receptor potential
change in the resting potential of a receptor cell in response to stimuli, which may initiate an action potential
sensory transduction
converting environmental stimuli into action potentials the brain can understand
somatosensory system
body sensations:
can determine whether body
sensations arise from outside or within the body
ca ndetermine whether body sensations arise from outside or in the body
receptive field
stimulus region and features that affect the activity of a cell in a sensory system
sensory adaptation
progressive decrease in a receptors response to sustained stimulation
phasic receptors
frequency of action potentials drops rapidly as stimulation is maintained
tonic receptors
frequency of action potentials decline slowly or not at all as stimulation is maintained
central modulation of sensory information
higher brain centers, such as the cortex and thalamus, suppress some sources of sensory information and amplify others
dermatome
a strip of skin innervated by a particular spinal nerve
primary sensory cortex
generally the initial destination of sensory inputs to the cortex
polymodal neurons
a neuron upon which information from more than one sensory system converges
synesthesia
a filter, that only the most important stimuli are selected for special processing
pain
an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage
nociceptors
respond to stimuli that produce tissue damage or pose the threat of damage
A delta fibers
large, myelinated, and fast-conducting axon that usually transmits pain info
C fibers
small, unmyelinated axon that conducts pain information slowly and adapts slowly
anterolateral system
somatosensory system that carries most of the pain and temperature information from the body to the brain
substance P
peptide transmitter that is involved in pain transmission
neuropathic pain
pain that persists long after the injury that started it has healed
analgesia
absence of or reduction of pain
endorphines
endogenous opioid
transcutaneous electrical nerve stimulation
mild electrical stimulation is applied to nerves around the injury sites to relieve pain
motor plan
complex set of commands to muscles that is established before an act occurs
electromyography (EMG)
electrical recording of muscle activity
synergists
a muscle that acts together with another muscle
neuromuscular junctions
where the motor neuron terminal meets its target muscle fiber and transmits messages
motor neurons
final common pathway, sole route through which the spinal cord and brain can control many muscles
proprioception
body sense; information about the position and movement of the body
(muscle spindle and golgi tendon organs)
muscle spindle
signals the central nervous system when the muscle is lengthened
intrafusal fiber
any of the small muscle fibers that lie within each muscle spindle
golgi tended organs
sends impulses to the central nervous system when a muscle contracts/ sensitive to muscle tension
pyramidal (corticospinal) system
includes neurons within the cerebral cortex and their axons, which form the pyramidal tract
extrapyramidal system
axons of this system pass into the spinal cord outside the pyramids of the medulla, interfere with spinal reflexes, and systems that regulate and fine-tune motor behavior
primary motor cortex M1
apparent executive region for the initiation of movement primarily the precentral gyrus
nonprimary motor cortex
contribute to motor control and modulate the activity of the primary motor cortex (supplementary motor area and premotor cortex)
supplementary motor area
receives input from the basal ganglia and modulates the activity of the primary motor cortex (initiation of movement)
plegia
paralysis
paresis
weakness
apraxia
inability to carry out complex movements even though paralysis or weakness is not evident and language comprehension and motivation are intact
two most important sources of extrapyramidal fibers
- basal ganglia: amplitude, direction, and initiation of movement from memory
- cerebellum: skilled movements (rapid, repeated movement that become automatic)
ataxia
loss of coordination
decomposition of movement
gestures are broken up into individual segments instead of being smooth
parkinsons disease
progressive deteriotion of dopamine-containing cells in the substantia nigra (slow movement, hand tremors, rigid bearing, diminished facial expressions
transient receptor potential vanilloid type 1 (TRPV 1)
detects heat
hyperalgesia
following a painful stimulus associated with tissue damage, stimuli in the area of the injury and the surrounding region are perceived as significantly more painful
basal ganglia
modulate movement, amplitude and direction of movement
-movement performed by memory rather than by sensory control
peripheral sensitization
interaction of nociceptors with the “inflammatory soup” of substances released when tissue is damaged
central sensitization
rapid onset, activity-dependent increase in the excitability of neurons in the dorsal horn of the spinal cord following high levels of activity in the nociceptive afferents
cerebellum
receives inputs from sensory sources and other brain motor systems
-guides movement through inhibition
-helps fine tune skilled movements
Huntington’s disease
clumsiness, twitches, involuntary jerks (damage to caudate nucleus and putamen in basal ganglia)
