Final answer:
The corticospinal tract is a key descending tract of the central nervous system that controls voluntary muscle movements through upper and lower motor neurons. It passes through various brain regions and undergoes pyramidal decussation in the medulla before controlling different muscle groups.
Step-by-step explanation:
Descending Corticospinal Tract
The corticospinal tract is a major descending tract in the central nervous system that controls skeletal muscle movements. It is composed of an upper motor neuron, whose cell body is located in the primary motor cortex of the frontal lobe, and a lower motor neuron located in the ventral horn of the spinal cord. The upper motor neuron synapses on the lower motor neuron, which in turn projects to the skeletal muscle.
This tract travels from the cortex through the cerebral white matter, between the basal nuclei, and down into the brainstem, going through the midbrain and pons to reach the medulla. Here, the pyramidal decussation occurs, where many of the fibers cross to the opposite side of the brain before the tract separates into different parts that control various muscle domains.
The anterior corticospinal tract controls trunk muscles and coordinates postural adjustments, whereas the decussation allows movements of the body directed by both sides of the brain. This organization ensures precise and coordinated motor control over our skeletal muscles.