Podcast
Questions and Answers
Which column is responsible for both ascending and descending tracts?
Which column is responsible for both ascending and descending tracts?
Which type of sensory information is carried in ascending tracts?
Which type of sensory information is carried in ascending tracts?
How many neurons are typically involved in the circuit of ascending tracts?
How many neurons are typically involved in the circuit of ascending tracts?
Which pathway is responsible for carrying light touch and vibration information?
Which pathway is responsible for carrying light touch and vibration information?
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Which neurons enter the spinal cord via the dorsal root?
Which neurons enter the spinal cord via the dorsal root?
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Where do first-order neurons synapse on second-order neurons in the medulla?
Where do first-order neurons synapse on second-order neurons in the medulla?
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Which tract is responsible for carrying pain, thermal, and non-discriminative touch information?
Which tract is responsible for carrying pain, thermal, and non-discriminative touch information?
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Where do second-order neurons cross in the spinal cord?
Where do second-order neurons cross in the spinal cord?
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Which part of the spinal cord receives sensory input?
Which part of the spinal cord receives sensory input?
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Which part of the spinal cord contains motor neuronal cell bodies?
Which part of the spinal cord contains motor neuronal cell bodies?
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Which part of the spinal cord is expanded at levels that supply the limbs?
Which part of the spinal cord is expanded at levels that supply the limbs?
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Which tracts carry afferent (sensory) impulses to centers within the brain?
Which tracts carry afferent (sensory) impulses to centers within the brain?
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Which tracts carry efferent (motor) impulses from centers within the brain?
Which tracts carry efferent (motor) impulses from centers within the brain?
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Which region of the spinal cord has lateral horns only in the thoracic region?
Which region of the spinal cord has lateral horns only in the thoracic region?
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Which part of the spinal cord organization has excellent organization of the dorsal, ventral, and lateral horns?
Which part of the spinal cord organization has excellent organization of the dorsal, ventral, and lateral horns?
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Which part of the spinal cord contains tracts that carry sensory impulses to/from the cerebral hemispheres?
Which part of the spinal cord contains tracts that carry sensory impulses to/from the cerebral hemispheres?
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Which tract carries proprioceptive information from the trunk and lower limb?
Which tract carries proprioceptive information from the trunk and lower limb?
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Which tract carries proprioceptive information from the upper limb?
Which tract carries proprioceptive information from the upper limb?
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Where do the spinocerebellar tracts terminate?
Where do the spinocerebellar tracts terminate?
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Which tract ascends in the lateral column to the cerebellum?
Which tract ascends in the lateral column to the cerebellum?
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What is the main function of the corticospinal tract?
What is the main function of the corticospinal tract?
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How many neurons are there in the corticospinal tract pathway?
How many neurons are there in the corticospinal tract pathway?
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Where do the upper motor neurons in the corticospinal tract originate from?
Where do the upper motor neurons in the corticospinal tract originate from?
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Where do the lower motor neurons in the corticospinal tract originate from?
Where do the lower motor neurons in the corticospinal tract originate from?
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What is the clinical presentation of upper motor neuron disease?
What is the clinical presentation of upper motor neuron disease?
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Which part of the spinal cord contains the cell bodies of lower motor neurons?
Which part of the spinal cord contains the cell bodies of lower motor neurons?
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What is the function of the dorsal horn in the spinal cord?
What is the function of the dorsal horn in the spinal cord?
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Which part of the spinal cord is responsible for innervating skeletal muscles?
Which part of the spinal cord is responsible for innervating skeletal muscles?
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What is the basic organization of the spinal cord?
What is the basic organization of the spinal cord?
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Which part of the spinal cord contains more grey matter?
Which part of the spinal cord contains more grey matter?
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Which tracts carry motor information from the brain down towards the spinal cord and out towards the periphery?
Which tracts carry motor information from the brain down towards the spinal cord and out towards the periphery?
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Which type of sensory information is carried in the ascending tracts?
Which type of sensory information is carried in the ascending tracts?
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Where do the primary sensory neurons (first-order neurons) enter the spinal cord?
Where do the primary sensory neurons (first-order neurons) enter the spinal cord?
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Which pathway is responsible for carrying information about light touch and vibrations?
Which pathway is responsible for carrying information about light touch and vibrations?
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What type of information is carried in the dorsal column medial lemniscus pathway?
What type of information is carried in the dorsal column medial lemniscus pathway?
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Where do the first-order neurons of the dorsal column medial lemniscus pathway synapse on second-order neurons?
Where do the first-order neurons of the dorsal column medial lemniscus pathway synapse on second-order neurons?
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Which part of the spinal cord contains tracts that carry sensory impulses to/from the cerebral hemispheres?
Which part of the spinal cord contains tracts that carry sensory impulses to/from the cerebral hemispheres?
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Which region of the spinal cord contains tracts that carry sensory impulses to/from the cerebral hemispheres?
Which region of the spinal cord contains tracts that carry sensory impulses to/from the cerebral hemispheres?
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Which part of the spinal cord is expanded at levels that supply the limbs?
Which part of the spinal cord is expanded at levels that supply the limbs?
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What is the main function of the corticospinal tract?
What is the main function of the corticospinal tract?
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Which column in the spinal cord is responsible for carrying ascending and descending tracts?
Which column in the spinal cord is responsible for carrying ascending and descending tracts?
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Which tracts are responsible for carrying proprioceptive information from the upper and lower limbs respectively?
Which tracts are responsible for carrying proprioceptive information from the upper and lower limbs respectively?
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Which side of the cerebellum controls the left side of the body?
Which side of the cerebellum controls the left side of the body?
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Where do the pyramidal tracts pass through?
Where do the pyramidal tracts pass through?
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Which pathway controls all of the skeletal muscles?
Which pathway controls all of the skeletal muscles?
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Which part of the brain receives information from the third order neurons in the somatic sensory pathway?
Which part of the brain receives information from the third order neurons in the somatic sensory pathway?
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What is the term used to describe the loss of balance and coordination due to a lack of proprioceptive input to the somatic sensory cortex?
What is the term used to describe the loss of balance and coordination due to a lack of proprioceptive input to the somatic sensory cortex?
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What is the clinical test used to assess for sensory ataxia in patients with lesions of the dorsal column?
What is the clinical test used to assess for sensory ataxia in patients with lesions of the dorsal column?
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Which tract carries information about pain, thermal sensations, and non-discriminative touch to the brain?
Which tract carries information about pain, thermal sensations, and non-discriminative touch to the brain?
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Which part of the brain stem do the axons of the upper motor neurons pass through?
Which part of the brain stem do the axons of the upper motor neurons pass through?
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Which part of the medulla do the axons of the upper motor neurons enter?
Which part of the medulla do the axons of the upper motor neurons enter?
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What do the axons of the upper motor neurons form within the medulla?
What do the axons of the upper motor neurons form within the medulla?
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What percentage of fibers in the corticospinal tract cross the midline to enter the spinal cord?
What percentage of fibers in the corticospinal tract cross the midline to enter the spinal cord?
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What is the main function of the corticospinal tract?
What is the main function of the corticospinal tract?
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Which parts of the motor cortex innovate the lower limb and upper limb, respectively?
Which parts of the motor cortex innovate the lower limb and upper limb, respectively?
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Study Notes
Spinal Cord Tracts and Functions
- The spinal cord columns responsible for both ascending and descending tracts are the dorsal and ventral columns.
- Ascending tracts carry sensory information such as touch, pain, vibration, proprioception, and temperature to the brain.
- Typically, three neurons are involved in the circuit of ascending tracts: first-order, second-order, and third-order neurons.
- The dorsal column-medial lemniscus pathway is responsible for carrying light touch and vibration information.
- Afferent fibers of sensory neurons enter the spinal cord via the dorsal root.
- In the medulla, first-order neurons synapse on second-order neurons in the nuclei of the dorsal column.
- The spinothalamic tract carries pain, thermal, and non-discriminative touch information.
- Second-order neurons typically cross at the spinal cord level before ascending to the brain.
- The dorsal horn of the spinal cord receives sensory input.
- The ventral horn contains motor neuronal cell bodies.
- Enlargements in the spinal cord occur at levels that supply the limbs.
- Ascending tracts carry sensory impulses to the brain; descending tracts carry motor impulses from the brain.
Spinal Cord Organization and Regional Functions
- Lateral horns are present only in the thoracic region of the spinal cord.
- The cervical and lumbar enlargements show excellent organization of the dorsal, ventral, and lateral horns.
- Sensory tracts to and from the cerebral hemispheres are found in the lateral regions of the spinal cord.
- The spinocerebellar tracts carry proprioceptive information from both the trunk and limbs.
- The dorsal spinocerebellar tract carries proprioceptive information from the lower limb, while the cuneocerebellar tract carries it from the upper limb.
- The spinocerebellar tracts typically terminate in the cerebellum.
- The lateral spinothalamic tract ascends to the cerebellum through the lateral column.
Corticospinal Tract and Motor Function
- The main function of the corticospinal tract is to control voluntary motor function.
- There are two neurons in the corticospinal tract pathway: upper and lower motor neurons.
- Upper motor neurons originate from the motor cortex.
- Lower motor neurons originate from the ventral horn of the spinal cord.
- Clinical presentation of upper motor neuron disease includes spasticity, weakness, and hyperreflexia.
- The dorsal horn has the function of processing sensory information.
- The ventral horn is responsible for innervating skeletal muscles.
- Grey matter is more abundant in regions where spinal nerves exit to the limbs.
Pathways and Impacts on Coordination and Balance
- Descending tracts carry motor information from the brain to the spinal cord and out to the body.
- Primary sensory neurons enter the spinal cord through the dorsal root.
- The dorsal column-medial lemniscus pathway is key for light touch and vibration sensory input.
- The first-order neurons of this pathway synapse on second-order neurons in the medulla.
- Each ascending tract plays a specific role in transmitting sensory information to the brain, including proprioception and pain.
- The right cerebellum controls the left side of the body due to crossovers in the neural pathways.
- Axons of upper motor neurons pass through the brainstem and enter the medulla.
- In the medulla, these axons form the pyramids of the corticospinal tract.
- About 80% of the fibers in the corticospinal tract cross at the decussation of the pyramids before entering the spinal cord.
- Parts of the motor cortex for limb control are organized with specific regions innovating the lower limb versus the upper limb.
Clinical Aspects and Assessments
- Sensory ataxia, characterized by loss of balance and coordination due to poor proprioception input, can be assessed using clinical tests.
- Dorsal column lesions can lead to difficulty in maintaining balance, often evaluated through specific balance tests.
- Clinical evaluation and assessment techniques are fundamental for diagnosing spinal functionality and motor control issues.
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Description
Test your knowledge on the ascending and descending tracts of the spinal cord in this quiz. Explore the anatomy of the spinal cord, including its grey and white matter. Learn about the functions and disorders of cerebrospinal fluid and the ventricular system. Join Professor Andrew Dilley for a comprehensive review of these important topics.