Muscle, Motor System, and Proprioception in Neuroscience

What type of muscles are used for movement of the skeleton?

Skeletal muscles, made of striated muscle.

What proteins are skeletal muscles primarily composed of?

Myosin and actin.

What happens to muscle fibers during contraction?

The overlap of actin and myosin filaments increases, causing the muscle fiber to shorten.

What are fast-twitch fibers known for?

They contract rapidly but fatigue easily.

What are slow-twitch fibers known for?

They contract with low intensity but fatigue slowly.

What are motor neurons?

Neurons that transmit neural messages to muscles.

What is the neuromuscular junction?

The region where the motor neuron terminal meets its target muscle fiber.

What neurotransmitter is released at the neuromuscular junction?

Acetylcholine (ACh).

What is a motor unit?

The motor neuron and the muscle fibers it innervates.

What is proprioception?

The collection of information about body movements and position.

What is the role of muscle spindles?

They send impulses to the CNS when the muscle is stretched.

What do Golgi tendon organs do?

They send impulses to the CNS when a muscle contracts.

What is the pyramidal system?

The corticospinal system that includes neurons from the cerebral cortex.

What does the extrapyramidal system include?

The basal ganglia and related brainstem structures.

What is the primary motor cortex?

The major source of axons forming the pyramidal tract, located in the precentral gyrus.

What is the function of the supplementary motor area (SMA)?

Important for the initiation of movement sequences, especially preplanned ones.

What is apraxia?

The inability to carry out a complex action due to damage in nonmotor zones of the cerebral cortex.

What are mirror neurons?

Neurons that fire both when making a movement and when observing another individual make the same movement.

What is ataxia?

Loss of movement coordination.

What characterizes Parkinson's disease?

Tremors at rest, muscular rigidity, and reduction in voluntary movement due to loss of dopaminergic neurons.

What is Huntington's disease?

A genetic disorder causing abrupt, involuntary writhing movements and changes in mental functioning.