Final answer:
The pyramidal tract, specifically the lateral corticospinal tract, is responsible for the control of fine, discrete movements of the extremities. The extrapyramidal system modulates movements and contributes to posture but is not directly responsible for fine motor control.
Step-by-step explanation:
The pyramidal tract is involved in the control of fine, discrete movements of the extremities. This tract descends from the cortex through the deep white matter of the cerebrum, passes through the internal capsule, midbrain, pons, and enters the medulla where it makes up the large white matter tract known as the pyramids. The lateral corticospinal tract, which is part of the pyramidal tract, is composed of fibers that cross at the pyramidal decussation in the medulla to the lateral column of the spinal cord and are responsible for controlling appendicular muscles.
The extrapyramidal system includes pathways between the brain and spinal cord that are separate from the corticospinal tract and are responsible for modulating movements generated through the primary pathway. It comprises several tracts such as the reticulospinal tract that modulate movement, contribute to posture, and regulate muscle tone without direct involvement in the precision control imparted by the pyramidal tract.