What is the Motor function of nervous system?

Motor function of the nervous system refers to the ability of the brain to control and coordinate movement. It involves several neural pathways and components working together to receive sensory information, process it, and send motor commands to the muscles. The motor function of the nervous system can be divided into two primary components: upper motor neurons and lower motor neurons.

1. Upper Motor Neurons:

Upper motor neurons originate in the motor cortex of the brain, particularly the primary motor cortex (area 4) and premotor cortex. These neurons transmit voluntary motor commands from the brain to the lower motor neurons in the brainstem and spinal cord.

Functions:

- Initiation of movement: Upper motor neurons receive signals from other areas of the brain involved in planning and coordinating movements, such as the basal ganglia and cerebellum. They then send signals to initiate voluntary muscle contractions.

- Control of muscle tone: Upper motor neurons help maintain muscle tone, the partial contraction of muscles, which keeps the body in an upright posture and prepares it for movement.

2. Lower Motor Neurons:

Lower motor neurons originate in the brainstem and spinal cord and extend to the muscles. They are the final pathway for transmitting motor commands from the upper motor neurons to the muscles.

Functions:

- Innervation of muscles: Lower motor neurons innervate skeletal muscles, forming neuromuscular junctions where they release acetylcholine to stimulate muscle contraction.

- Reflex actions: Lower motor neurons are also involved in reflex actions, which are involuntary, rapid responses to stimuli that bypass the brain.

Motor Pathways:

The motor pathways consist of the neural connections between the upper and lower motor neurons. The main motor pathways include:

- Corticospinal (pyramidal) tract: This pathway carries motor commands directly from the motor cortex to the lower motor neurons in the spinal cord. It is responsible for skilled and voluntary movements.

- Extrapyramidal tracts: These pathways, including the rubrospinal, vestibulospinal, and tectospinal tracts, originate from various regions of the brainstem and assist in coordinating movement, maintaining balance, and controlling muscle tone.

The motor function of the nervous system allows us to perform various movements, from simple actions like walking and talking to complex tasks like playing a musical instrument or writing. Damage or dysfunction to any part of the motor pathway can lead to movement disorders, such as paralysis, muscle weakness, or impaired coordination.