60 Questions
Which part of the spinal cord receives sensory input?
Dorsal horn
Which part of the spinal cord contains motor neuronal cell bodies?
Ventral horn
Which part of the spinal cord is expanded at levels that supply the limbs?
Lumbosacral enlargement
Which type of tracts carry sensory impulses to centers within the brain?
Long ascending tracts
Which type of tracts carry motor impulses from centers within the brain?
Long descending tracts
Which tracts are crossed and connect to/from the cerebral hemispheres?
Efferent tracts
Which part of the spinal cord contains preganglionic sympathetic neurons?
Lateral horn
Which part of the spinal cord has excellent organization of the dorsal, ventral, and lateral horns?
Grey matter organisation
Which part of the spinal cord is expanded at the thoracic region only?
Lateral horn
Which part of the spinal cord contains columns/tract/funiculi?
White matter
Which tract carries proprioceptive information from the trunk and lower limb?
Spinocerebellar tracts
Which tract carries proprioceptive information from the upper limb?
Corticospinal tract
Where do the spinocerebellar tracts terminate?
In the cerebellum on the same side
Which tract is responsible for unconscious muscle proprioception?
Spinocerebellar tracts
Which tract carries voluntary motor signals from the cerebral cortex to the ventral horn?
Corticospinal tract
Where do the upper motor axons pass through before reaching the spinal cord?
Cerebral peduncle
Where do the nerve fibers decussate within the corticospinal tract?
In the medulla
What is the result of degeneration of upper motor neurons in the corticospinal tract?
Spastic paralysis
What is the result of degeneration of lower motor neurons in the ventral horn?
Flaccid paralysis
Which disease selectively affects both lower and upper motor neurons?
Amyotrophic lateral sclerosis
Which part of the brain controls the right side of the body?
Left cerebral hemisphere
Which column in the spinal cord is responsible for descending tracts?
Ventral column
Which type of sensory information is carried in ascending tracts?
Proprioceptive information
How many neurons are typically involved in the ascending tracts circuit?
Three
Which pathway provides the brain with positional information?
Dorsal column-medial lemniscus pathway
Where do the first-order neurons synapse with the second-order neurons in the dorsal column-medial lemniscus pathway?
Medulla
Which tract carries pain and temperature information?
Spinothalamic tract
Where do the second-order neurons cross in the spinothalamic tract?
Spinal cord
What is the result of damage to the dorsal column on one side of the spinal cord?
Loss of tactile discrimination and proprioception on the same side
What is the result of damage to the anterolateral column on one side of the spinal cord?
Loss of pain and temperature on the same side
Which topic will the lecture focus on after discussing the anatomy of the spinal cord?
Somatosensory receptors
What is one of the main functions of the spinal cord at the level of the central nervous system?
Sensory stimulus discrimination
What are the fundamental building blocks of involuntary behaviors in all animals, including humans?
Simple reflexes
Which part of the lecture is considered the most important?
Effects of spinal lesions
Which type of convergence is needed when detecting weak signals?
High convergence
What is the best example of a case requiring high divergence?
The inputs used for complex or multiple functions
What is the function of the primary sensory neurons?
To generate receptor potentials
What is an adequate stimulus for all types of receptors?
A specific stimulus
Which type of receptors are responsible for detecting sharp objects on the skin?
Nociceptors
What is the purpose of using a compass in the experiment described in the text?
To detect stimuli with greater spatial resolution
Which part of the body has a higher density of receptors, allowing for greater spatial resolution?
Hands
Which type of receptors are responsible for detecting cold and warm sensations?
Thermoreceptors
Which of the following is NOT true about the receptors responsible for stimulus discrimination?
Receptors are primarily responsible for information processing in the spinal cord
Which receptor is best at detecting shielding forces on the skin?
Meissner Corpuscular
What is the structure surrounding a single nerve fiber in the Chilean court receptor?
Onion-like layers
What type of receptor is the O'Neill structure?
O'Neill
Which of the following is NOT a main physiological function of the spinal cord?
Integration of sensory and motor information
What is the difference between sensation and perception?
Sensation is the detection of external stimuli, while perception is the interpretation of those stimuli by the spinal cord and brain circuits.
What is the role of receptors in the nervous system?
Receptors are cells specialized in the transduction of energy generated by external stimuli.
What is the importance of convergence and divergence in the nervous system?
Convergence allows multiple neurons to provide input to a single neuron downstream, while divergence allows inputs and outputs from a neuron to reach a greater number of neurons.
Which of the following statements about the motor system is true?
The motor system consists of all muscles and the neurons that command them
What is the role of the lower motor neurons in the spinal cord?
They are the final common path for all signals from the central nervous system to the skeletal muscles
What did the experiment with the cat on a treadmill reveal about the spinal cord?
The spinal cord can generate complex motor patterns independently of the brain
How are the lower motor neurons organized in the spinal cord?
They are collected in longitudinally organized columns
Which type of motor neurons predominantly make the muscles contract?
Large motor neurons
What is the role of smaller gamma motor neurons in the motor system?
To provide proprioception
What is the purpose of using fluorescent dyes or dyes like cobalt and nickel in visualizing lower motor neurons?
To visualize the columns of lower motor neurons
What is the result of damage to the large motor neurons in the motor system?
Loss of muscle contraction
What are the two types of motor neurons found in each column of the motor system?
Large and small motor neurons
What is the main focus of the discussion in the text?
The link between anatomy and function
Study Notes
Ascending and Descending Tracts of the Spinal Cord
- The spinal cord consists of grey matter (horns) and white matter (columns/tract/funiculi).
- Grey matter is organized into dorsal, ventral, and lateral horns, each with specific functions.
- The grey matter is expanded at levels that supply the limbs, resulting in cervical and lumbosacral enlargements.
- The white matter contains ascending and descending tracts that carry sensory and motor impulses to and from the brain.
- Ascending tracts carry sensory information, including proprioceptive and exteroceptive inputs.
- The dorsal column-medial lemniscus pathway is an ascending tract that carries light touch, vibration, and proprioceptive information.
- The pathway involves three neurons: first-order, second-order, and third-order neurons.
- The spinothalamic tract is another ascending tract that carries pain, temperature, and non-discriminative touch information.
- The spinothalamic tract also involves three neurons and crosses in the dorsal horn at each level.
- The spinocerebellar tracts are ascending tracts that carry unconscious muscle proprioception for smooth motor coordination.
- The spinocerebellar tracts have different pathways for the trunk and lower limb, and the upper limb.
- Descending tracts control muscular activity and are divided into pyramidal and extrapyramidal tracts.
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.
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