spinal reflexes Flashcards
which has larger axon: specific sensors or general sensors
specific
what do muscle spindles do
send info on muscle length (and therefore somewhat on velocity). Run in PARALLEL w/muscle
two sensory afferents in muscle spindle
1a) largest in body, the stretch receptors 2) slower
what senses muscle force
tendon organs. Run in SERIES with muscle
what senses heat, pressure, pH, pain
free nerve endings
1a afferents: what kind of synapse, what does it stimulate, what reflexes, what purpose
monosynaptic excitation of homonymous muscle and synergist and inhibition of antagonists. Tendon tap reflex, stretch reflex, enhances muscle stiffness
pacinian corpulses
mechanoreceptors responding to vibration and pressure.
what could you do to increase the tendon tap reflex
serotonin reuptake inhibitors
what is the purpose of the stretch reflex
increases muscle stiffness so muscle behaves more like spring. Recruits more motor units
what is the order of the flexion (withdrawal) reflex
Cutaneous afferents to cord, crossed extension reflex, withdrawal reflex, pain sensation (LAST).
where is the central pattern generator for locomotion
spinal cord. You can improve locomotion with training even in cord injury
explain spasticity in spinal cord injury
uncontrolled flexion reflex. Lose cxn to presynaptics which release monoamines but You get less and less post trans modification of receptors which increases constitutive activity.
how do you inhibit spasms in spinal cord injury
GABA agonist, also serotonin and NE (via different receptors, excitatory for motor neurons, inhibitory in dorsal horn for flexion reflex)
