Ch 13 anatomy
spinal nerves are
both sensory and motor
____ reflexes activate skeletal muscles
somatic
information communicated through the ventral root of the spinal cord
somatic motor, visceral motor
examples of brain modifying reflex patterns
when someone holds their breath, when a person deliberately walks on hot coals, when someone keeps postponing emptying a full urinary bladder
nerve tracts or fasciculi make up the
white columns
positive babinski reflex
a sign of injury to descending spinal tracts, abnormal in adults, flaring of the toes when the sole is stroked, normal in newborns
neural reflexes
are the simplest form of behavior, are automatic motor responses, help preserve homeostasis, involve at least two neurons
reflex arc
arrival of stimulus and activation of receptor, activation of a sensory neuron, information processing in the CNS, activation of a motor neuron, response by effector
the ventral root of a spinal nerve contains
axons of motor neurons
the dorsal root of a spinal nerve contains
axons of sensory neurons
in meningitis
bacteria can be the cause, viruses can be the cause, inflammation of the meninges occurs, CSF flow can be disrupted
the white matter of the spinal cord contains
bundles of axons with common origins, destinations, and functions
the dorsal root ganglia mainly contain
cell bodies of sensory neurons
the dorsal root ganglia consist mainly of
cell bodies of unipolar neurons
the spinal cord is part of the ____ nervous system
central
reflexes that activate muscles on the opposite side of the body as the stimulus are called
contralateral
the ____ reflex complements the flexor reflex by activating contralateral muscles
crossed extensor
the ____ of each spinal nerve innervates the skin and muscles of the back
dorsal ramus
the tough, fibrous, outermost covering of the spinal cord is the
dura mater
neuronal pools are described as
functional groups of interconnected neurons
reflexes based on synapses formed during development are ____ reflexes
innate
essential components of a monosynaptic reflex
input of a sensory neuron, receptor activation, output to a peripheral effector
the most complicated spinal reflexes are called
intersegmental reflex arcs
reflexes that activate muscles on the same side of the body as the stimulus are called
ipsilateral
during the procedure known as ______, a needle is inserted into the subarachnoid space in the inferior lumbar region
lumbar puncture
the flexor reflex
moves a limb away from a painful stimulus
interneurons are organized into functional groups called
neuronal pools
pain sensation, withdrawal of hand, and auditory comment
parallel neuronal circuit
the layer of the meninges in direct contact with the spinal cord is the
pia mater
the cerebrospinal fluid is confined between the ____ and the _____
pia mater; arachnoid mater
the _____ gray horns contain sensory nuclei
posterior
the condition in which a person loses all feeling and movement of the arms and legs due to spinal cord injury is termed
quadriplegia
the neural "wiring" of a single reflex is called
reflex arc
clenching the fists often enhances the knee jerk reflex. this is an example of
reinforcement
the dorsal root contains ____ neurons
sensory
if the dorsal root of a spinal nerve is severed,
sensory input would be blocked
the posterior horns of the spinal cord contain mainly
sensory nuclei
a reflex arc always includes
sensory receptor, afferent axon, efferent axon
Immediate and intense pain sensation
serial processing
a dorsal and ventral root of each spinal segment unite to form a
spinal nerve
the polysynaptic reflex that limits muscle tension is the ____ reflex
tendon
the subdural space lies between
the dura mater and the arachnoid mater
anesthetics administered into the epidural space are advantageous because
the effect is localized and only sensory
the major anatomical difference between gray matter and white matter is ____
the presence of myelinated axons
damage to which branch of the spinal nerve is likely only to have an effect on the muscles of the limbs
the ventral ramus
reflexes can be classified according to
their development, where information processing occurs, the complexity of the neural circuit, the motor response
the spinal cord consists of four regions and ____ segments
thirty-one