13.5-13.8 Flashcards
neuronal pool
functional groups of interconnected interneurons
Patterns of neural circuits in neuronal pools
divergence
convergence
serial processing
parallel processing
reverberation
divergence
spreads info from 1 neuron or neuronal pool to many
- common in sensory pathways
convergence
several neurons synapse on a single neuron
serial processing
neurons or pools work sequentially
parallel processing
several neurons/neuronal pools process the same info at the same time
- ex: stepping on a sharp object
reverberation
a positive feedback circuit
neural reflex
rapid, automatic response to specific stimuli
reflex arc
the route followed by nerve impulses to produce a reflex
5 steps in a reflex arc
- Stimulus activates a receptor
- Activation of a sensory neuron
- Information processing in the C N S
- Activation of a motor neuron – interneurons stimulate action potentials in motor neuron
- Response by a peripheral effector
classification of reflexes (8)
innate
acquired
somatic
visceral
monosynaptic
polysynaptic
spinal
cranial
innate reflex
basic neural reflexes formed before birth
- ex: chewing
acquired reflex
rapid, automatic learned motor patterns
somatic reflexes
allow for immediate involuntary control of muscular system
visceral reflex
control internal organs
monosynaptic reflex
involve a single synapse
polysynaptic reflex
involve at least 1 interneuron between the sensory neuron and the motor neuron + involves multiple synapse
spinal reflexes
processing occurs in the spinal cord
cranial reflexes
processing occurs in the brain
types of monosynaptic reflexes
stretch reflex
postural reflexes
stretch reflex
regulates skeletal muscle length
- ex: knee jerk
muscle spindle
sensory receptors involved in a stretch reflex
intrafusal muscle fibers
small specialized skeletal muscle that make up muscle spindle
muscle spindle function
stretching the intrafusal fibers increases the frequency of action potentials fired by the sensory neuron
postural reflexes
help maintain normal upright posture
examples of polysynaptic reflexes
tendon reflex
withdrawal reflexes
crossed extensor reflexes
tendon reflex
prevents skeletal muscles from developing too much tension and tearing or breaking tendons
withdrawal reflexes
move body part away from a stimulus (pain or pressure)
reciprocal inhibition
When one set of motor neurons is stimulated, those neurons that control antagonistic muscles are inhibited
ipsilateral reflex arcs
occur on the same side of the body as the stimulus
plantar reflex
curling of toes when lateral sole of foot is stroked
spinal nerve anatomy
- epineurum
-blood supply - fasicles (bundles of neurons)
- perineurium (covers fascicles)
- endoneurium (covers individual neuron/axon)
- schwann cell (myelinates axons)
anterior gray horn
contain somatic motor neurons that send information from the spinal cord to skeletal muscles.
central canal
the opening between the gray commissures that contains cerebrospinal fluid
fibrous connective tissue layer that attaches to the bony walls of the spinal cord
dura mater
dorsal ramus
branch of the peripheral nerves supplies the skin and muscles of the back
how many cervical and thoracic nerves
8 cervical
12 thoracic
how many lumbar and sacral nerves
5 lumbar
5 sacral
5 PLEXUS
cervical
brachial
lumbar
sacral
coccygeal
dorsal root function
carries sensory information from the PNS to the CNS
ventral root function
sending motor signals from the CNS to the body’s skeletal muscles/effectors
spinal cord belongs to ___ and spinal nerve belongs to ___
CORD: CNS
NERVE: PNS
