stimulus
All neural reflexes begin with a _______ that activates a sensory receptor.
Somatic motor neurons
Efferent division that controls skeletal muscles
Autonomic neurons
Efferent division that control smooth and cardiac muscle, glands, and adipose tissue
F
T/F Spinal reflexes require input from the brain
F, within
T/F Cranial reflexes are integrated outside of the brain
1. efferent division that controls the effector
2. Integrating region within the central nervous system
3. time at which the reflex develops
4. the number of neurons in the reflex pathway
Neural reflexes can be classified by:
spinal cord
Where are spinal reflexes integrated?
cranial reflexes
reflexes that are integrated in the brain are called what?
T
T/F spinal and cranial reflexes can be modulated by a higher input from the brain
F
T/F many reflexes are learned instead of innate
monosynaptic reflex
What is the name of the simplest reflex?
monosynaptic reflex
this reflex is name for the single synapse between the two neurons in the pathway: an afferent sensory neuron and an efferent somatic motor neuron.
one
how many synapses does a monosynaptic reflex have?
polysynaptic reflex
this reflex have three of more neurons in the pathway and at least two synapses
interneuron in spinal cord
Where does the first synapse of a polysynaptic reflex end?
excitation or inhibition
Modulation in polysynaptic pathways may involve _____ and ______.
input from the brain
Some visceral reflexes are spinal reflexes that can take place without ___________.
hypothalamus, thalamus, brain stem
Where specifically are autonomic reflexes integrated into the brain? (3)
polysynaptic
All autonomic reflexes are what kind of reflex?
autonomic reflexes are all polysynaptic, with at lease one synapse in the CNS between the sensory neurons and the preganglionic autonomic neuron, and an additional synapse in the ganglion between the preganglionic and postganglionic neurons.
autonomic reflexes and their synapses
tonic activity, a continuous stream of action potentials that creates ongoing activity in the effector.
many autonomic reflexes are characterized by what?
skeletal muscle, joint capsules, and ligaments
proprioceptors are located where? (3)
input sensory neurons
Proprioceptors carry ________ to the CNS
output signal
Somatic motor neurons carry _______.
activate somatic motor neurons to the muscle fibers
if there is a muscle contraction then the CNS will do what?
sensory input activated inhibitory interneuorns in the CNS, and these interneurons inhibit activity in somatic neurons controlling the muscle
If a muscle needs to be relaxed what will happen in the CNS?
F, excitation causes contraction
T/F relaxation always causes contraction in skeletal muscle
F
T/F there are inhibitory neurons that synapses on skeletal muscles to cause them to relax
excitatory input by the somatic motor neuron
relaxation of the muscle results from the absence of what?
synapses within the CNS
inhibition and excitation of somatic motor neurons and their associated skeletal muscles must occurs where?
extrafusal muscle fbers
normal contractile fibers (effectors)
excitatory and inhibitory interneurons
the CNS integrates the input signal using networks and pathways of
alpha motor neurons
Somatic motor neurons that innervate skeletal muscle contractile fibers are called what?
extrafusal fibers
action potentials in alpha motor neurons causes what to contract?
muscle spindles, golgi tendon organs, and joint receptors
what are the three types of proprioceptors found in the body?
joint receptors
these receptors are found in capsules and ligaments around joints in the body.
muscle spindles and golgi tendon organs
these receptors lie inside skeletal muscles and sense changes in muscle length and tension (2)
muscle reflexes
the sensory output of muscle spindles and golgi tendon organs activates what?
muscle spindles
stretch receptors that send information to the spinal cord and brain about muscle length and changes in muscle length
muscle spindles
small, elongated structures scattered among and arranged parallel to the contractile extrafusal muscle fibers
jaw
every skeletal muscle in the body has muscle spindles except where?
in muscle spindles
where are intrafusal fibers located?
intrafusal fibers
connective tissue CAPSULE that encloses a group of small muscle fibers
intrafusal fibers
these fibers are modified so that the ends are contractile but the central region lack myofibrils
gamma motor neurons
the contractile ends of the intrafusal fibers have their own innervation from what?
sensory nerve endings that are stimulated by stretch
noncontractile central region of each intrafusal fiber is wrapped by what?
sensory receptors
muscle spindles and golgi tendon organs are _______ in muscle.
on alpha motor neurons innervating the muscle in which the spindle lies
the sensory nerve endings that is located in the central region of intrafusal fibers project to the spinal cord and synapse directly where?
resting, active
when a muscle is at its ______ length, the central region of each muscle spindle is stretched enough to activated the sensory fibers. As a result, sensory neurons from the spindles are tonically ____, sending a steady stream of action potentials to the CN
muscle tone
when muscle at rest maintains a certain level of tension
parallel
muscle spindles are anchored in ____ to the extrafusal muscle fibers
stretch reflex
the reflex pathway in which muscle stretch initiates a contraction response
muscle spindle
this part of the muscle sends tonically active sensory neuron with information to the CNS
F, resting
T/F sensory neurons are tonically active when muscle fibers are contraction
F, presence of gamma motor neurons in a normal muscle keeps the muscle spindles active, no matter what the muscle length is.
T/F the release of tension on the center of the intrafusal fibers will cause the afferent neurons to slow their firing rate or stop firing altogether.
...
when alpha motor neurons fire, the muscle shortens and releases tension on the muscle spindle capsule. Simultaneously, gamma motor neurons innervating the contractile ends of the muscle spindle fire, which causes the ends of intrafusal fibers to contract
contraction of the spindle ends
what causes the central region of the spindle to lengthen and maintain stretch on the sensory nerve endings?
active
spindle remains ____ when the muscle contracts
alpha-gamma coactivation
Excitation of gamma motor neurons and alpha motor neurons at the same time is called
yes
when extrafusal muscle fibers are at resting length, are sensory neurons tonically active?
alpha motor neurons
what receives the tonic input from muscle spindles?
decrease
without gamma motor neurons, muscle contraction cause the spindle firing rate to _____.
stretched
alpha-gamma coactivation keeps the spindles ____ when the muscle contracts
golgi tendon organ
these receptors are found at the junction of tendons and muscle fibers, placing them in series with the muscle fibers
golgi tendon organ
what responds primarily to the tension that a muscle develops from an isometric contractions
isometric
this type of contraction causes a relaxation reflex
f
T/F golgi tendon organ is more sensitive to muscle stretch than the muscle spindles
golgi tendon organ
composed of free nerve endings that wind between collagen fibers inside a connective tissue capsule
inhibitory
afferent input from activation of the golgi tendon organ excited ____ interneurons in the spinal cord.
excessive contraction that might injure the muscle
golgi tendon organs prevent what?
myotatic unit
collection of pathways controlling a single joint
monosynaptic stretch reflex
simplest reflex in a myotatic unit
sesnory neuron from the muscle spindle and the somatic motor neuron to the muscle
the monosynaptic stretch reflex involves which two neurons?
flexion reflexes
polysynaptic reflex pathways that cause an arm or leg to be pulled away from a painful stimulus
divergent pathways
flexion reflexes rely on what kind of pathways in the spinal cord?
crosses extensor reflex
flexion reflexes are usually accompanied by what other reflex?
divergence
this allows the sensory signal to permit a single stimulus to control two sets of antagonistic muscle groups as well as to send sensory information to the brain.
reflex, voluntary, rhythmic
3 types of movement
reflex movement
least complex movement and is integrated primarily in the spinal cord
T
T/F reflex movements can be modulated by input form higher brain centers.
postural reflexes
these reflexes help us maintain body position as we stand or move through space and are integrated in the brain stem
postural reflexes
these reflexes require continuous sensory input form visual and vestibular sensory systems and from the muscles themselves
voluntary movement
this is the most complex type of movement. They require integration at the cerebral cortex and they can be initiated at will without external stimuli
rhythmic movements
this type of movement is the combination of reflex and voluntary movements
cerebral cortex
rhythmic movements are initiated and terminated by input from which part of the brain?
rhythmic
central pattern generators (CPGs) are interneurons that are activated during which type of movement?
brain stem and cerebellum
which parts of the brain control postural reflexes and hand and eye movements?
cerebral cortex and basal ganglia
which parts of the brain help intiate voluntary movement?
spinal cord
this part of the body integrates spinal reflexes and contains central pattern generators.
thalamus
this part of the brain relays and modifies signals being sent from the spinal cord, basal ganglia, and cerebellum to the cerebral cortex
F
T/F reflex movements require input from the cerebral cortex
spinal cord, brain stem, and cerebellum
proprioceptors provide information to which parts of the brain
F, directly goes to the cerebellum
T/F sensory input from the vestibular apparatus go to the spinal cord, cerebral cortes, and cerebellum
basal nuclei, cortical association areas, cerebellum
planning movement happens where in the brain?
motor cortex
initiating movement happens where in the brain?
corticospinal tract
a group of interneurons controlling voluntary movement that run form the motor cortex to the spinal cord, where they synapse directly onto somatic motor neurons
parkinson's disease
this disease is caused by the loss of basal ganglia that release dopamine
visceral movement
moves products in hollow organs, controlled by ANS, some create own action potentials