Movement is controlled by motor neurons that innervate muscles. Motor neurons can be classified by their location as upper motor neurons or lower motor neurons.
Upper motor neurons have cell bodies in the somatosensory and motor cortex of the brain that send axons down to the spinal cord or brainstem. Upper motor neurons descend through the posterior limb of the internal capsule in the cerebrum, through the crus cerebri of the midbrain, through the basilar pons, through the medullary pyramids, crossing midline at the pyramidal decussation in the caudal medulla, and descending through the anterior and lateral corticospinal tracts of the spinal cord to terminate at their respective ventral horn levels. Corticobulbar fibers are upper motor neurons that innervate brainstem nuclei for cranial nerves. They descend through the genu of the internal capsule of the cerebrum to various brainstem cranial nerve nuclei or reticular formation nuclei that innervate brainstem cranial nerve nuclei.
Lower motor neurons have cell bodies in the ventral horns throughout the spinal cord. These motor neurons receive excitation information from the upper motor neurons as well as a large amount of modulating input from a variety of other neuronal sources. For cranial nerves the lower motor neurons are located within the brainstem cranial nerve nuclei: occulomotor nucleus, trochlear nucleus, abducens nucleus, trigeminal motor nucleus, facial nucleus, spinal accessory nucleus, hypoglossal nucleus, & nucleus ambiguous.
Many upper motor neurons synapse with lower motor neurons in the ventral horn of the spinal cord. This is where the cell bodies of lower motor neurons are located, allowing for the direct control of muscle function.
Upper motor neurons are responsible for initiating voluntary movements by sending signals from the brain to the lower motor neurons in the spinal cord. They play a crucial role in coordinating and executing motor functions throughout the body. Dysfunction of upper motor neurons can result in symptoms such as muscle weakness, spasticity, and impaired coordination.
Lower motor neurons have cell bodies located in the spinal cord or brainstem. They carry motor information from the central nervous system to the muscles, enabling voluntary muscle movement. Damage to lower motor neurons can result in muscle weakness, atrophy, and a loss of reflexes.
The descending pathway from the red nucleus to the lower motor neurons is known as the rubrospinal tract. This tract plays a role in the coordination of movement and the regulation of muscle tone, particularly in the upper limbs. It originates in the red nucleus of the midbrain and descends to influence motor neurons in the spinal cord, primarily facilitating flexor muscle activity.
Upper motor neuron cell bodies are situated in the motor cortex and project axons via the corticospinal tracts to the spinal cord. There they synapse in the anterior horn with lower motor neurons, which project axons via peripheral nerves that then contact muscle fibres at the neuromuscular junction. Lower motor neurons originating in the brain stem that control speech and swallowing (bulbar motor neurons), and lower motor neurons that originate in the spinal cord that control limb and respiratory muscles, may both be affected. Damage to various combinations of upper and lower motor neurons occurs in human amyotrophic lateral sclerosis.
Many upper motor neurons synapse with lower motor neurons in the ventral horn of the spinal cord. This is where the cell bodies of lower motor neurons are located, allowing for the direct control of muscle function.
You are probably speaking of "lower motor neurons." These are neurons that send information from the spinal cord to the muscles of the body & they travel within all most of the nerves of the body (like sciatic, median, etc). These neurons are controlled by "upper motor neurons" and control your muscles to allow you to be able to move.
Upper motor neurons are responsible for initiating voluntary movements by sending signals from the brain to the lower motor neurons in the spinal cord. They play a crucial role in coordinating and executing motor functions throughout the body. Dysfunction of upper motor neurons can result in symptoms such as muscle weakness, spasticity, and impaired coordination.
two motor neurons are always involved in descending motor pathways. the upper motor neuron and the lower motor neuron.
Lower motor neurons have cell bodies located in the spinal cord or brainstem. They carry motor information from the central nervous system to the muscles, enabling voluntary muscle movement. Damage to lower motor neurons can result in muscle weakness, atrophy, and a loss of reflexes.
The plane is about to descend to a lower altitude.
No. To descend means to move to a lower level as in an elevator or on a stairway.
descend; become lower
The descending pathway from the red nucleus to the lower motor neurons is known as the rubrospinal tract. This tract plays a role in the coordination of movement and the regulation of muscle tone, particularly in the upper limbs. It originates in the red nucleus of the midbrain and descends to influence motor neurons in the spinal cord, primarily facilitating flexor muscle activity.
Upper motor neuron cell bodies are situated in the motor cortex and project axons via the corticospinal tracts to the spinal cord. There they synapse in the anterior horn with lower motor neurons, which project axons via peripheral nerves that then contact muscle fibres at the neuromuscular junction. Lower motor neurons originating in the brain stem that control speech and swallowing (bulbar motor neurons), and lower motor neurons that originate in the spinal cord that control limb and respiratory muscles, may both be affected. Damage to various combinations of upper and lower motor neurons occurs in human amyotrophic lateral sclerosis.
upper motor neurons
Upper Motor Neurons