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