Question

The two types of motor neurons perform different activities: The upper motor neuron ____________ the activity of the lower motor neuron, but the lower motor neuron always ____________ because its axon connects directly to the ____________ . The cell bodies of motor neurons and most interneurons involved in the innervations and control of limb and trunk muscles reside in the spinal cord ____________ and the gray matter zone between the anterior horn and the posterior horn. The neurons that innervate the head and neck are located in the motor nuclei of cranial nerves and in the ____________ . Motor neuron axons form two types of motor pathways: The ____________ pathways are responsible for conscious control of skeletal muscle activity; the ____________ pathways are responsible for subconscious or unconscious control.

Answer 1

The two types of motor neurons perform different activities: The upper motor neuron excites or inhibits the activity of the lower motor neuron, but the lower motor neuron always is excitatory because its axon connects directly to the skeletal muscle fibers. The cell bodies of motor neurons and most interneurons involved in the innervations and control of limb and trunk muscles reside in the spinal cord anterior horn and the gray matter zone between the anterior horn and the posterior horn. The neurons that innervate the head and neck are located in the motor nuclei of cranial nerves and in the reticular formation. Motor neuron axons form two types of motor pathways: The direct pathways are responsible for conscious control of skeletal muscle activity; the undirect pathways are responsible for subconscious or unconscious control.