textbook W3D1 Flashcards
dorsal side of spinal chord has BLANK nerves
efferent/motor
ventral side of spinal chord has BLANK nerves
afferent/sensory
what do the efferent and afferent nerves combine to form
spinal nerves
name the four spinal regions (including numbers)
cervicle (C1-C7), thoracic (T1-T12), lumbar (L1-L5), sacral (S1-S5)
sensory neurons carry info BLANK CNS
TO the CNS
motor neurons carry info BLANK CNS
AWAY FROM the CNS
mixed neurons have BLANK
both sensory and motor fibers
most neurons in the body are BLANK neurons
mixed
what columns/horns are white matter
dorsal column, ventral horn, lateral column
dorsal column (location)
posterior side of spinal chord
ventral horn (location)
anterior side of spinal chord
lateral column (location)
lies between dorsal column and ventral horn
what horns/columns are made of gray matter
dorsal horn, ventral horn, lateral horn
dorsal horn
loaction of sensory synapses
ventral horn
location of motor neurons
lateral horn
location of cell bodies in autonomic nervous system
where are the cell bodies of ALL somatosensary receptor neurons located
DORSAL ROOT GANGLION
where are the cell bodies of alpha motor neurons located
ventral horn of spinal chord
where do the axons of alpha motor neurons go
leave spinal chord via ventral roots and travel to the muscle via EFFERENT spinal nerves
what is myasthenia gravis (MG)
autoimune disorder characterized by weak facial muscles (droopy eyes, double vision, etc).
results from disctruction of nicitinic ACh receptors at neuromuscular junctions causing weak or no contractions of facial muscles
motor unit (def)
alpha motor neuron + all the muscle fibers that it innervates
motor pool (def)
group of motor neurons that innervate all the fibers of one muscle
slow motor unit (def)
slow to contract, generate less force but can work for a long time. used during endurance work (ex running)
fast fatigue-resistant motor units (def)
quick to contract, generate more force than slow motor units and are more resistant to fatigue than fast fatiguable
fast fatigable motor units (def)
quickest to contract and generate the most force. prone to fatigue due to fewer mitochondria within muscles. used in high-intensity exercise (ex. weighlifting, sprinting)
unfused tetanus (def)
short time between stimuli, but far enough apart that the muscle fiber has a partial relaxation period
fused tetanus (def)
if action potentials are close enough together, they will summate and cause one large contraction
muscle recruitment
smallest motor units are activated first and ‘recruit’ larger ones as necessary (lifting pencil vs 20 lbs)
sensory cells from dorsal root ganglion (function)
provide sensory info from muscles through propreoception
upper motor neurons from motor cortex in brain + brainstem (function)
are responsible for innitiating voluntary movement
interneurons in spinal chord (function)
largest input to alpha neurons, can provide excitation or inhibition to alpha motor neurons
proprioceptors (function)
inform us about body position + movement in space
muscle spindles (function)
measure muscle stretch (length) + transmit this info via 1a sensory fibers. nested within and arranged parallel to the extrafusal muscle fibers
golgi tendon organs (function)
measure muscle tension + transmit this sensory info via 1b sensory fibers. located between extrafusal muscle fibers and their points of attachement to bone
extrafusal + intrafusal muscle fibers (def)
fiberous cpsuls located within muscles (muscle spindle)
intrafusal muscle fiber (def)
located within fiberous capsul of muscle spindle. innervated by gamma motor neurons that cause them to contract
extrafusal muscle fiber (def)
make up bulk of muscle, located outside muscle spindle. stimulated to contract by alpha motor neurons
golgi tendon organ (def)
propreoceptor that measure muscle tention/force of contraction
golgi tendon organ (location)
inside tendon that connects muscle to bone
reflex (def)
involuntary motor response performed automatically and independantly of brain signals
myotatic reflex (def)
knee jerk reflex
stretch reflex that occurs in response to activation of the muscle spindle stretch receptors
monosynaptic communication (def)
only one synapse between the sensory input and motor output
