27 Questions
Where is the leg represented in relation to the face in the cortical representations?
Most medially
Which anatomical level of the spinal cord is thickest?
Cervical
What is the origin of the lateral corticospinal tract?
Primary motor cortex of the brain
Where does the lateral corticospinal tract cross to the opposite side?
Junction between the medulla and spinal cord
Which division of the nervous system is involved in 'fight-or-flight' functions?
Sympathetic division
Where do parasympathetic efferents arise from?
Brainstem and sacral spinal nuclei
What type of neurotransmitter does the parasympathetic division use?
Acetylcholine
Which descending motor pathway is clinically the most important?
Lateral corticospinal tract
What are the efferents arising from the thoracolumbar spinal cord known as?
Sympathetic efferents
What can patterns of weakness be useful for in a clinical context?
Localizing lesions in the nervous system
Where does the lateral corticospinal tract descend through?
Ventral pons
At which anatomical location does the lateral corticospinal tract cross to the opposite side?
Junction between the medulla and spinal cord
What is the clinical significance of the lateral corticospinal tract?
Most clinically important pathway in the nervous system
Where does the lateral corticospinal tract originate mainly?
Primary motor cortex
Which part of the spinal cord is thickest?
Cervical region
What structure do fiber bundles along the ventral medulla form?
Lateral corticospinal tract
Which part of the brain does the lateral corticospinal tract descend through?
Pons
What is the main function of the lateral corticospinal tract?
Voluntary motor control
Which descending motor pathway is involved in controlling voluntary movements, particularly of the distal musculature?
Rubrospinal tract
What type of neurotransmitter does the sympathetic division use on end organs?
Norepinephrine
Which descending motor pathway is involved in the control of postural muscles and reflex movements?
Reticulospinal tract
What are efferents arising from the thoracolumbar spinal cord known as?
Sympathetic efferents
Which descending motor pathway originates from the superior and inferior colliculi and is involved in reflex head movements in response to visual and auditory stimuli?
Tectospinal tract
What are the two main divisions of the autonomic nervous system?
Sympathetic and parasympathetic divisions
Where does the parasympathetic division synapse in preparation for reaching its end organs?
Brainstem and sacral spinal nuclei
Which neurotransmitter does the parasympathetic division use as its peripheral neurotransmitter on end organs?
Acetylcholine
Which division of the nervous system subserves 'rest and digest' functions, such as increased salivation and peristalsis?
Parasympathetic division
Study Notes
Cortical Representations and Spinal Cord
- The leg is represented in the cortical representations in the medial part of the primary motor cortex, adjacent to the face.
- The cervical enlargement level of the spinal cord is the thickest.
Lateral Corticospinal Tract
- The lateral corticospinal tract originates from the primary motor cortex and premotor cortex.
- The lateral corticospinal tract crosses to the opposite side at the medullospinal junction.
- The tract descends through the ventral funiculus of the spinal cord and is involved in controlling voluntary movements, particularly of the distal musculature.
- The tract originates mainly from the contralateral primary motor cortex and premotor cortex.
Autonomic Nervous System
- The sympathetic nervous system is involved in 'fight-or-flight' functions, and the parasympathetic nervous system is involved in 'rest and digest' functions, such as increased salivation and peristalsis.
- The parasympathetic efferents arise from the cranial nerves III, VII, IX, and X, and the sacral spinal cord.
- The parasympathetic division uses acetylcholine as its peripheral neurotransmitter on end organs and synapses in the ganglia in preparation for reaching its end organs.
Descending Motor Pathways
- The lateral corticospinal tract is clinically the most important and is involved in controlling voluntary movements, particularly of the distal musculature.
- The efferents arising from the thoracolumbar spinal cord are known as the sympathetic nervous system.
- The tectospinal tract originates from the superior and inferior colliculi and is involved in reflex head movements in response to visual and auditory stimuli.
Clinical Significance
- Patterns of weakness can be useful for localizing lesions in a clinical context.
- The lateral corticospinal tract is clinically significant due to its involvement in controlling voluntary movements, particularly of the distal musculature.
Test your knowledge of neuroanatomy with this quiz on motor and sensory pathways, including cortical representations and the appearance of the spinal cord at different levels. Explore the clinically important corticospinal tract and its anatomy.
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