Podcast
Questions and Answers
What is the primary function of the myelin sheath?
What is the primary function of the myelin sheath?
Which type of tract carries motor information down the spinal cord?
Which type of tract carries motor information down the spinal cord?
What is the name of the structure where fibers cross over in the ventral white column?
What is the name of the structure where fibers cross over in the ventral white column?
Which tract carries fine touch, vibration, and proprioception information?
Which tract carries fine touch, vibration, and proprioception information?
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What is the name of the tract that allows pain and temperature fibers to ascend one to two segments before synapsing on posterior gray horn neurons?
What is the name of the tract that allows pain and temperature fibers to ascend one to two segments before synapsing on posterior gray horn neurons?
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What is the arrangement of the lateral corticospinal tract in terms of somatotopic organization?
What is the arrangement of the lateral corticospinal tract in terms of somatotopic organization?
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Which tract primarily stimulates flexors?
Which tract primarily stimulates flexors?
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What is the function of the ventral spinocerebellar tract?
What is the function of the ventral spinocerebellar tract?
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What is the function of the spino-olivary tract?
What is the function of the spino-olivary tract?
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What is the function of the anterior spinothalamic tract?
What is the function of the anterior spinothalamic tract?
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Study Notes
Here are the study notes:
White Matter and Neurons
- White matter: consists of myelinated axons, which gives a whitish appearance
- Myelin sheath: a lipid protein sheet surrounding the axon, allowing for action potentials to be carried quickly
- Neuron structure: has dendrites (receptive region), cell body (nucleus), axon terminal (axon bulb), and myelin sheath
Tracts
- Tract: a bundle of axons in the central nervous system
- Ascending tracts: carry sensory information up the spinal cord
- Descending tracts: carry motor information down the spinal cord
Anatomy of White Matter in the Spinal Cord
- Columns: white columns or funiculi (dorsal, lateral, ventral)
- Dorsal white column: posterior to gray matter
- Lateral white column: on the side of gray matter
- Ventral white column: anterior to gray matter
- Anterior white commissure: a structure where fibers cross over in the ventral white column
Function of White Matter
- Ascending tracks: carry sensory information (e.g., pain, temperature) up the spinal cord
- Descending tracks: carry motor information (e.g., voluntary control of skeletal muscles) down the spinal cord
Specific Tracts
- Lateral corticospinal tract: a descending motor tract in the lateral white column; stimulates lower motor neurons for voluntary control of skeletal muscles
- Rubrospinal tract: a descending motor tract in the lateral white column
- Dorsal column tracts: ascending sensory tracts in the dorsal white column, carrying fine touch, vibration, and proprioception (position and movement) information
- Lateral spinothalamic tract: an ascending sensory tract in the lateral white column, carrying pain and temperature information
- Anterior spinothalamic tract: an ascending sensory tract in the anterior white column, carrying pain and temperature information
- Tractus de Lasauer: an ascending tract that allows pain and temperature fibers to ascend one to two segments before synapsing on posterior gray horn neurons
Somatotopic Arrangement
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Lateral corticospinal tract: legs are laterally, with sacral supply most laterally, then lumbar, thoracic, and cervical
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Dorsal column: sacral supply is most medially, then lumbar, thoracic, and cervical
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Lateral spinothalamic tract: legs are laterally, with sacral supply most laterally, then lumbar, thoracic, and cervical### Descending Tracts in Lateral White Column
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Lateral reticulospinal tract (also known as medullary reticulospinal tract) primarily stimulates flexors
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Medial reticulospinal tract (also known as pontine reticulospinal tract) primarily supplies extensors
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Vestibulospinal tract primarily stimulates extensors, specifically anti-gravity muscles
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Tectospinal tract sends information for movement of the head, neck, and eye movements
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Ventral or anterior corticospinal tract stimulates lower motor neurons for voluntary skeletal muscle control
Ascending Tracts in Lateral White Column
- Dorsal spinocerebellar tract picks up proprioceptive sensations from C8 to L2 via Clark's column
- Ventral spinocerebellar tract picks up proprioceptive sensations from L2 to the coccygeal region
- Spino-olivary tract picks up proprioception and sends information to the inferior olives, which then sends it to the cerebellum via climbing fibers
- Lateral spinothalamic tract carries pain and temperature sensations
- Anterior spinothalamic tract carries crude touch and pressure sensations
White Matter and Neurons
- White matter composition: myelinated axons, giving a whitish appearance
- Myelin sheath function: allows for rapid action potential transmission
- Neuron structure components: dendrites, cell body, axon terminal, and myelin sheath
Tracts
- Tract definition: a bundle of axons in the central nervous system
- Ascending tracts function: carry sensory information up the spinal cord
- Descending tracts function: carry motor information down the spinal cord
Spinal Cord Anatomy
- White columns: dorsal, lateral, and ventral columns (funiculi)
- Dorsal white column location: posterior to gray matter
- Lateral white column location: on the side of gray matter
- Ventral white column location: anterior to gray matter
- Anterior white commissure function: fibers cross over in the ventral white column
White Matter Functions
- Ascending tracts sensory information: pain, temperature, etc.
- Descending tracts motor information: voluntary control of skeletal muscles
Specific Tracts
- Lateral corticospinal tract function: stimulates lower motor neurons for voluntary control of skeletal muscles
- Rubrospinal tract function: descending motor tract
- Dorsal column tracts sensory information: fine touch, vibration, and proprioception
- Lateral spinothalamic tract sensory information: pain and temperature
- Anterior spinothalamic tract sensory information: pain and temperature
- Tractus de Lasauer function: allows pain and temperature fibers to ascend before synapsing
Somatotopic Arrangement
- Lateral corticospinal tract organization: legs are laterally, with sacral supply most laterally
- Dorsal column organization: sacral supply is most medially
- Lateral spinothalamic tract organization: legs are laterally, with sacral supply most laterally
Descending Tracts in Lateral White Column
- Lateral reticulospinal tract function: stimulates flexors
- Medial reticulospinal tract function: supplies extensors
- Vestibulospinal tract function: stimulates extensors, specifically anti-gravity muscles
- Tectospinal tract function: sends information for head, neck, and eye movements
- Ventral or anterior corticospinal tract function: stimulates lower motor neurons for voluntary skeletal muscle control
Ascending Tracts in Lateral White Column
- Dorsal spinocerebellar tract function: picks up proprioceptive sensations from C8 to L2
- Ventral spinocerebellar tract function: picks up proprioceptive sensations from L2 to the coccygeal region
- Spino-olivary tract function: picks up proprioception and sends it to the cerebellum
- Lateral spinothalamic tract function: carries pain and temperature sensations
- Anterior spinothalamic tract function: carries crude touch and pressure sensations
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Description
Learn about the structure and function of white matter, neurons, and tracts in the central nervous system. Understand the components of a neuron and how they work together to transmit information.
