120 Questions
Which type of tracts deliver information to the brain?
Ascending tracts
What is the function of the posterior funiculus?
Primarily ascending tracts
Which tract delivers information from the spinal cord to the cerebellum?
Spinocerebellar tract
What is the role of the lateral funiculus?
Both ascending and descending tracts
Where are the fibers of the ascending tracts derived from?
Spinal nerves
What is a characteristic of funiculus in the spinal cord?
Large bundles known as fasciculi
How are tracts named in relation to the spinal cord?
"Spino" for sensory tracts and "spinal" for motor tracts
Where is the cell body of the second-order neuron in the spinothalamic tract located?
Spinal cord
Which sensations are carried by the lateral spinothalamic tract?
Pain and temperature
What is the clinical manifestation of a lesion in the spinothalamic tract in the brain stem or spinal cord?
Contralateral loss of pain and temperature
Which tracts carry discriminative touch, joint position sense, vibration, and pressure sensation?
Dorsal column-medial lemniscal pathway
What is the function of the spinocerebellar tracts?
Carry sensory information from the spinal cord to the cerebellum for monitoring and modulating movements
Which tract carries tactile, pressure, and proprioceptive input from muscle spindles and GTO to the cerebellum for monitoring and modulating movements?
Posterior spinocerebellar tract
What is astereognosis associated with?
Dorsal column-medial lemniscal lesions
Which sensory receptor is imbedded in tendons of skeletal muscles and monitors the degree of tension and force placed on the skeletal muscle?
Golgi tendon organs (GTO)
Which pathway is responsible for reflex postural movements in response to visual stimuli?
Tectospinal Tract
Lesions above the decussation of the corticospinal tract result in weakness seen in muscles on which side of the body?
Contralateral side
What is the characteristic response of an upper motor neuron (UMN) lesion?
Increase in muscle tonus followed by sudden decrease in resistance to stretch
Which descending pathway inhibits or facilitates voluntary movement and has some fibers that cross the midline at various levels?
Reticulospinal Tract
What is the function of the Rubrospinal Tract?
Facilitates activity of extensor muscles
Which descending pathway facilitates activity of extensor muscles and inhibits activity of flexor muscles?
Vestibulospinal Tract
Which descending pathway originates from the red nucleus in the mid-brain and facilitates activity of flexor muscles?
Rubrospinal Tract
Which fibers control autonomic systems and originate from the cortex, hypothalamus, amygdala, and reticular formation?
Descending Autonomic Fibers
Which descending tract in the spinal cord carries afferent information for spinovisual reflexes?
Spinotectal tract
Which tract in the spinal cord carries afferents influencing levels of consciousness?
Spinoreticular tract
Which descending tract in the spinal cord carries balance and unconscious proprioceptive afferent information to the cerebellum?
Spinoolivary tract
Which neural circuit is involved in initiating a voluntary contraction of skeletal muscle?
UMN and LMN
Where are the cell bodies of UMN located?
Brain stem and cerebral cortex
Which reflex is the simplest and involves only one synapse between 1 sensory and 1 motor neuron?
Deep muscle stretch (myotatic) reflex
Which tract is responsible for the voluntary innervation of skeletal muscle, descending through the brain stem?
Corticospinal Tract
Which type of tracts carry discriminative touch, joint position sense, vibration, and pressure sensation?
Posterior funiculus
Where are the cell bodies of upper motor neurons (UMNs) located?
In the cerebral cortex
What is the function of the rubrospinal tract?
Facilitates activity of extensor muscles
Which descending pathway originates from the red nucleus in the mid-brain and facilitates activity of flexor muscles?
Rubrospinal tract
What is the characteristic response of an upper motor neuron (UMN) lesion?
Hypertonia and hyperreflexia
Which descending tract in the spinal cord carries afferent information for spinovisual reflexes?
Tectospinal tract
Which neurons are used in the grey matter and tracts of axons in the grey matter of the spinal cord?
First-order neurons
Which descending tract in the spinal cord carries afferent information for spinovisual reflexes?
Spinotectal tract
Where do the corticospinal fibers descend through in the brain stem?
Ventral portion of the pons
Which tract carries balance and unconscious proprioceptive afferent information to the cerebellum?
Spinoolivary tract
Where do the corticospinal fibers cross at the decussation of the pyramids?
80-90%
Which descending pathway originates from the red nucleus in the midbrain and facilitates activity of flexor muscles?
Rubrospinal Tract
What is the characteristic response of an upper motor neuron (UMN) lesion?
Clonus
Which fibers control autonomic systems and originate from the cortex, hypothalamus, amygdala, and reticular formation?
Reticulospinal fibers
Where is the cell body of the third-order neuron in the spinothalamic tract located?
Thalamus
Which descending pathway is responsible for reflex postural movements in response to visual stimuli?
Tectospinal Tract
Which tract carries information related to pain, temperature, tickle, itch, and sexual sensations?
Anterior Spinothalmic Tract
Where are the cell bodies of gamma motor neurons located?
Anterior grey column
Which tract is responsible for carrying discriminative touch, joint position sense (kinesthetic), vibration, and pressure sensation?
Dorsal Column - Medial Lemniscal Pathway
What is the characteristic response of an upper motor neuron (UMN) lesion?
Increase in muscle tonus and resistance to stretch
Which tract carries tactile, pressure, and proprioceptive input from muscle spindles and GTO to the cerebellum for monitoring and modulating movements?
Posterior Spinocerebellar Tract
Which descending pathway originates from the red nucleus in the mid-brain and facilitates activity of flexor muscles?
Rubrospinal Tract
What is the clinical manifestation of a lesion in the spinothalamic tract in the brain stem or spinal cord?
Contralateral loss of pain and temperature
Which descending pathway inhibits or facilitates voluntary movement and has some fibers that cross the midline at various levels?
Reticulospinal Tract
What is astereognosis associated with?
Loss of ability to identify an object by touching with hands
What is the function of the Vestibulospinal Tract?
Facilitates activity of extensor muscles
Where do the fibers of the anterior spinocerebellar tract ultimately end?
Ipsilateral side
Where do the descending autonomic fibers controlling autonomic systems originate from?
Reticular formation
What is the role of the 1b afferent neurons stimulated by Golgi tendon organs?
Inhibit alpha motor neurons
Which descending pathway gives multiple branches at each level and represents about 30% of fibers going to the muscle?
Reticulospinal Tract
Where is the cell body of the third-order neuron in the spinothalamic tract located?
In the thalamus
Where do the corticospinal fibers descend through in the brain stem?
Pons
What is astereognosis associated with?
Inability to identify an object by touching with hands
Which descending pathway originates from the red nucleus in the midbrain and facilitates activity of flexor muscles?
Rubrospinal Tract
Which neural circuit is involved in initiating a voluntary contraction of skeletal muscle?
Reticulospinal Tract
Where are the cell bodies of gamma motor neurons located?
Spinal Cord
What is the function of the spinocerebellar tracts?
Monitor and modulate movements using sensory input from muscle spindles and GTO
Which type of tracts primarily carry information to the brain?
Ascending tracts
What is the specific function of the rubrospinal tract?
Inhibiting or facilitating voluntary movement
Where are the cell bodies of upper motor neurons (UMNs) located?
In the motor cortex of the brain
Which sensory receptor is embedded in tendons of skeletal muscles and monitors the degree of tension and force placed on the skeletal muscle?
Golgi tendon organ (GTO)
What is the clinical manifestation of a lesion in the spinothalamic tract in the brain stem or spinal cord?
Impaired pain and temperature sensation
Where do the corticospinal fibers cross at the decussation of the pyramids?
Cervical level of the spinal cord
Which descending pathway originates from the red nucleus in the mid-brain and facilitates activity of flexor muscles?
Rubrospinal tract
Which tract carries afferent information for spinovisual reflexes and terminates by synapsing on neurons in the superior colliculus?
Spinotectal tract
Which descending pathway inhibits or facilitates voluntary movement and has some fibers that cross the midline at various levels?
Rubrospinal Tract
Where are the fibers of the ascending tracts derived from?
Spinal Cord
What is the role of the lateral funiculus?
Facilitating activity of flexor muscles
Which sensory receptor is embedded in tendons of skeletal muscles and monitors the degree of tension and force placed on the skeletal muscle?
Golgi Tendon Organs (GTO)
What is astereognosis associated with?
Lesion in the Spinocerebellar tracts
Which neural circuit is involved in initiating a voluntary contraction of skeletal muscle?
UMN and LMN circuit
Which descending pathway originates from the red nucleus in the midbrain and facilitates activity of flexor muscles?
Rubrospinal Tract
What is the characteristic response of an upper motor neuron (UMN) lesion?
Increased muscle tonus and sudden decrease in resistance to stretch
Where are the cell bodies of gamma motor neurons located?
Anterior grey column
Which descending pathway is responsible for reflex postural movements in response to visual stimuli?
Tectospinal Tract
What is the role of the 1b afferent neurons stimulated by Golgi tendon organs?
Inhibit alpha motor neurons
Which descending pathway facilitates activity of extensor muscles and inhibits activity of flexor muscles?
Vestibulospinal Tract
Where do the corticospinal fibers cross at the decussation of the pyramids?
Medulla oblongata
Which tract carries tactile, pressure, and proprioceptive input from muscle spindles and GTO to the cerebellum for monitoring and modulating movements?
Spinocerebellar Tracts
What is the function of the Rubrospinal Tract?
Facilitates activity of extensor muscles
Which type of tracts primarily carry information to the brain?
Ascending tracts
What is the role of the lateral funiculus?
Facilitates intersegmental coordination
Where are the cell bodies of gamma motor neurons located?
Grey matter of the spinal cord
Which descending pathway inhibits or facilitates voluntary movement and has some fibers that cross the midline at various levels?
Rubrospinal tract
What is the characteristic response of an upper motor neuron (UMN) lesion?
Increased muscle tone and hyperreflexia
Where is the cell body of the third-order neuron in the spinothalamic tract located?
Thalamus
What is the function of the Vestibulospinal Tract?
Facilitates activity of extensor muscles and inhibits activity of flexor muscles
Where is the cell body of the third-order neuron in the spinothalamic tract located?
In the thalamus
Which tract carries pain, temperature, tickle, itch, and sexual sensations?
Lateral Spinothalamic Tract
Where do the axons of the second neuron in the dorsal column-medial lemniscal pathway cross midline and ascend as the medial tract in the brain stem?
Medulla
Which spinocerebellar tract is responsible for conveying tactile, pressure, and proprioceptive information from muscle spindles and GTO to the cerebellum?
Posterior Spinocerebellar Tract
What is the characteristic clinical manifestation of a lesion in the spinothalamic tract in the brain stem or spinal cord?
Ipsilateral loss of pain and temperature sensation
What is the clinical correlate of lesions in the dorsal column-medial lemniscal pathway?
Loss of discriminative touch and joint position sense
Where do the second-order neurons in the spinothalamic tract have their cell bodies located?
In the spinal cord
Which tract carries balance and unconscious proprioceptive afferent information to the cerebellum?
Spinoolivary tract
Where do the corticospinal fibers cross at the decussation of the pyramids?
80-90% of fibers cross at the decussation of the pyramids
What is the primary motor cortex responsible for?
Initiating voluntary contraction of skeletal muscle
Which neurons initiate involuntary motor responses to a sensory stimulus?
Sensory neurons
What is the characteristic response of an upper motor neuron (UMN) lesion?
Hyperreflexia and muscle atrophy
Which descending pathway originates from the red nucleus in the midbrain and facilitates activity of flexor muscles?
Rubrospinal tract
Which neural circuit is involved in initiating a voluntary contraction of skeletal muscle?
UMN and LMN circuit
Which descending pathway originates from the red nucleus in the mid-brain and facilitates activity of flexor muscles?
Rubrospinal Tract
What is the characteristic response of an upper motor neuron (UMN) lesion?
Increased resistance to muscle stretch followed by sudden decrease
Where are the cell bodies of gamma motor neurons located?
Anterior grey column
What is astereognosis associated with?
Inability to recognize objects by touch
Where do the descending autonomic fibers controlling autonomic systems originate from?
Reticular formation
Which descending pathway inhibits or facilitates voluntary movement and has some fibers that cross the midline at various levels?
Reticulospinal Tract
What is the function of the spinocerebellar tracts?
Deliver information from the spinal cord to the cerebellum for monitoring and modulating movements
Which type of tracts carry discriminative touch, joint position sense, vibration, and pressure sensation?
Posterior column-medial lemniscus pathway
Where are the cell bodies of upper motor neurons (UMNs) located?
Primary motor cortex
Study Notes
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Friedreich's Ataxia: three descending tracts in the spinal cord: Spinotectal, Spinoreticular, and Spinoolivary
-
Spinotectal tract: carries afferent information for spinovisual reflexes, terminates by synapsing on neurons in the superior colliculus
-
Spinoreticular tract: carries afferents influencing levels of consciousness, terminates on neurons in the reticular formation
-
Spinoolivary tract: carries balance and unconscious proprioceptive afferent information to the cerebellum, 3rd order neurons in the inferior olivary nuclei in the medulla, axons cross and enter the cerebellum
-
Sensory tracts: organization based on the site of origin, arranged in a somatotopic manner, medial-lateral rule: neurons that enter a lower level of the spinal cord are more medial, neurons that enter at a higher level are more lateral
-
Motor system: voluntary innervation of skeletal muscle, basic neural circuit: upper motor neuron (UMN) and lower motor neuron (LMN), initiating a voluntary contraction: an LMN must be innervated by a UMN, UMN: LMN: cell bodies in brain stem and cerebral cortex, cell bodies in the ventral horn of the spinal cord and cranial nerve nuclei in the brain stem, LMN (in spinal cord) axons exit the spinal cord in a ventral root, join and course with a spinal nerve, reach and synapse on a neuromuscular junction in skeletal muscle
-
Motor neuron groups in the spinal cord: Anterior Grey Column, Alpha Efferents: large, multipolar LMN of brainstem and spinal cord, innervate extrafusal muscle fibers of skeletal muscle, present in most segments, innervate skeletal muscles of neck, trunk, intercostals, abdominals, present in some cervical and lumbosacral segments, innervate the diaphragm, accessory nucleus, lumbosacral nucleus, Corticospinal Tract: voluntary innervation of skeletal muscle, primary motor cortex: precentral gyrus of the frontal lobe, corticospinal fibers descend through the brain stem in the ventral portion of the mid brain, pons, and medulla, corticospinal tract in the lower medulla: 80-90% of fibers cross at the decussation of the pyramids, continue in the contralateral part of the spinal cord as the lateral corticospinal tract, descend full length of the cord in the lateral part of the white matter, as it descends axons leave and enter the gray matter of the ventral horn to synapse on a LMN, corticospinal tract in the lower medulla: 80-90% of fibers cross at the decussation of the pyramids, corticospinal tract reflex innervation of skeletal muscle: involuntary motor responses to a sensory stimulus, requires a minimum of 2 neurons: a sensory neuron that initiates a motor response and lower motor neurons, reflexes range from simple 2-neuron circuits to more complex reflexes, deep muscle stretch (myotatic) reflex: simplest of the reflexes, involves only one synapse between 1 sensory and 1 motor neuron, tests the integrity of the reflex in the limbs provides important clinical information when assessing different types of motor weaknesses and dysfunction, present in most skeletal muscles, provides the important physiological mechanism of regulating and maintaining proper muscle tone throughout the skeletal muscular system.
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Friedreich's Ataxia: three descending tracts in the spinal cord: Spinotectal, Spinoreticular, and Spinoolivary
-
Spinotectal tract: carries afferent information for spinovisual reflexes, terminates by synapsing on neurons in the superior colliculus
-
Spinoreticular tract: carries afferents influencing levels of consciousness, terminates on neurons in the reticular formation
-
Spinoolivary tract: carries balance and unconscious proprioceptive afferent information to the cerebellum, 3rd order neurons in the inferior olivary nuclei in the medulla, axons cross and enter the cerebellum
-
Sensory tracts: organization based on the site of origin, arranged in a somatotopic manner, medial-lateral rule: neurons that enter a lower level of the spinal cord are more medial, neurons that enter at a higher level are more lateral
-
Motor system: voluntary innervation of skeletal muscle, basic neural circuit: upper motor neuron (UMN) and lower motor neuron (LMN), initiating a voluntary contraction: an LMN must be innervated by a UMN, UMN: LMN: cell bodies in brain stem and cerebral cortex, cell bodies in the ventral horn of the spinal cord and cranial nerve nuclei in the brain stem, LMN (in spinal cord) axons exit the spinal cord in a ventral root, join and course with a spinal nerve, reach and synapse on a neuromuscular junction in skeletal muscle
-
Motor neuron groups in the spinal cord: Anterior Grey Column, Alpha Efferents: large, multipolar LMN of brainstem and spinal cord, innervate extrafusal muscle fibers of skeletal muscle, present in most segments, innervate skeletal muscles of neck, trunk, intercostals, abdominals, present in some cervical and lumbosacral segments, innervate the diaphragm, accessory nucleus, lumbosacral nucleus, Corticospinal Tract: voluntary innervation of skeletal muscle, primary motor cortex: precentral gyrus of the frontal lobe, corticospinal fibers descend through the brain stem in the ventral portion of the mid brain, pons, and medulla, corticospinal tract in the lower medulla: 80-90% of fibers cross at the decussation of the pyramids, continue in the contralateral part of the spinal cord as the lateral corticospinal tract, descend full length of the cord in the lateral part of the white matter, as it descends axons leave and enter the gray matter of the ventral horn to synapse on a LMN, corticospinal tract in the lower medulla: 80-90% of fibers cross at the decussation of the pyramids, corticospinal tract reflex innervation of skeletal muscle: involuntary motor responses to a sensory stimulus, requires a minimum of 2 neurons: a sensory neuron that initiates a motor response and lower motor neurons, reflexes range from simple 2-neuron circuits to more complex reflexes, deep muscle stretch (myotatic) reflex: simplest of the reflexes, involves only one synapse between 1 sensory and 1 motor neuron, tests the integrity of the reflex in the limbs provides important clinical information when assessing different types of motor weaknesses and dysfunction, present in most skeletal muscles, provides the important physiological mechanism of regulating and maintaining proper muscle tone throughout the skeletal muscular system.
-
Friedreich's Ataxia: three descending tracts in the spinal cord: Spinotectal, Spinoreticular, and Spinoolivary
-
Spinotectal tract: carries afferent information for spinovisual reflexes, terminates by synapsing on neurons in the superior colliculus
-
Spinoreticular tract: carries afferents influencing levels of consciousness, terminates on neurons in the reticular formation
-
Spinoolivary tract: carries balance and unconscious proprioceptive afferent information to the cerebellum, 3rd order neurons in the inferior olivary nuclei in the medulla, axons cross and enter the cerebellum
-
Sensory tracts: organization based on the site of origin, arranged in a somatotopic manner, medial-lateral rule: neurons that enter a lower level of the spinal cord are more medial, neurons that enter at a higher level are more lateral
-
Motor system: voluntary innervation of skeletal muscle, basic neural circuit: upper motor neuron (UMN) and lower motor neuron (LMN), initiating a voluntary contraction: an LMN must be innervated by a UMN, UMN: LMN: cell bodies in brain stem and cerebral cortex, cell bodies in the ventral horn of the spinal cord and cranial nerve nuclei in the brain stem, LMN (in spinal cord) axons exit the spinal cord in a ventral root, join and course with a spinal nerve, reach and synapse on a neuromuscular junction in skeletal muscle
-
Motor neuron groups in the spinal cord: Anterior Grey Column, Alpha Efferents: large, multipolar LMN of brainstem and spinal cord, innervate extrafusal muscle fibers of skeletal muscle, present in most segments, innervate skeletal muscles of neck, trunk, intercostals, abdominals, present in some cervical and lumbosacral segments, innervate the diaphragm, accessory nucleus, lumbosacral nucleus, Corticospinal Tract: voluntary innervation of skeletal muscle, primary motor cortex: precentral gyrus of the frontal lobe, corticospinal fibers descend through the brain stem in the ventral portion of the mid brain, pons, and medulla, corticospinal tract in the lower medulla: 80-90% of fibers cross at the decussation of the pyramids, continue in the contralateral part of the spinal cord as the lateral corticospinal tract, descend full length of the cord in the lateral part of the white matter, as it descends axons leave and enter the gray matter of the ventral horn to synapse on a LMN, corticospinal tract in the lower medulla: 80-90% of fibers cross at the decussation of the pyramids, corticospinal tract reflex innervation of skeletal muscle: involuntary motor responses to a sensory stimulus, requires a minimum of 2 neurons: a sensory neuron that initiates a motor response and lower motor neurons, reflexes range from simple 2-neuron circuits to more complex reflexes, deep muscle stretch (myotatic) reflex: simplest of the reflexes, involves only one synapse between 1 sensory and 1 motor neuron, tests the integrity of the reflex in the limbs provides important clinical information when assessing different types of motor weaknesses and dysfunction, present in most skeletal muscles, provides the important physiological mechanism of regulating and maintaining proper muscle tone throughout the skeletal muscular system.
-
Friedreich's Ataxia: three descending tracts in the spinal cord: Spinotectal, Spinoreticular, and Spinoolivary
-
Spinotectal tract: carries afferent information for spinovisual reflexes, terminates by synapsing on neurons in the superior colliculus
-
Spinoreticular tract: carries afferents influencing levels of consciousness, terminates on neurons in the reticular formation
-
Spinoolivary tract: carries balance and unconscious proprioceptive afferent information to the cerebellum, 3rd order neurons in the inferior olivary nuclei in the medulla, axons cross and enter the cerebellum
-
Sensory tracts: organization based on the site of origin, arranged in a somatotopic manner, medial-lateral rule: neurons that enter a lower level of the spinal cord are more medial, neurons that enter at a higher level are more lateral
-
Motor system: voluntary innervation of skeletal muscle, basic neural circuit: upper motor neuron (UMN) and lower motor neuron (LMN), initiating a voluntary contraction: an LMN must be innervated by a UMN, UMN: LMN: cell bodies in brain stem and cerebral cortex, cell bodies in the ventral horn of the spinal cord and cranial nerve nuclei in the brain stem, LMN (in spinal cord) axons exit the spinal cord in a ventral root, join and course with a spinal nerve, reach and synapse on a neuromuscular junction in skeletal muscle
-
Motor neuron groups in the spinal cord: Anterior Grey Column, Alpha Efferents: large, multipolar LMN of brainstem and spinal cord, innervate extrafusal muscle fibers of skeletal muscle, present in most segments, innervate skeletal muscles of neck, trunk, intercostals, abdominals, present in some cervical and lumbosacral segments, innervate the diaphragm, accessory nucleus, lumbosacral nucleus, Corticospinal Tract: voluntary innervation of skeletal muscle, primary motor cortex: precentral gyrus of the frontal lobe, corticospinal fibers descend through the brain stem in the ventral portion of the mid brain, pons, and medulla, corticospinal tract in the lower medulla: 80-90% of fibers cross at the decussation of the pyramids, continue in the contralateral part of the spinal cord as the lateral corticospinal tract, descend full length of the cord in the lateral part of the white matter, as it descends axons leave and enter the gray matter of the ventral horn to synapse on a LMN, corticospinal tract in the lower medulla: 80-90% of fibers cross at the decussation of the pyramids, corticospinal tract reflex innervation of skeletal muscle: involuntary motor responses to a sensory stimulus, requires a minimum of 2 neurons: a sensory neuron that initiates a motor response and lower motor neurons, reflexes range from simple 2-neuron circuits to more complex reflexes, deep muscle stretch (myotatic) reflex: simplest of the reflexes, involves only one synapse between 1 sensory and 1 motor neuron, tests the integrity of the reflex in the limbs provides important clinical information when assessing different types of motor weaknesses and dysfunction, present in most skeletal muscles, provides the important physiological mechanism of regulating and maintaining proper muscle tone throughout the skeletal muscular system.
Test your knowledge of ascending sensory pathways in the nervous system with this quiz. Explore the spinotectal tract, spinoreticular tract, and spinoolivary tract, and understand their roles in transmitting afferent information for various reflexes and functions.
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