Physiology of Behavior - Movement

A series of flashcards focusing on the physiology of behavior, particularly movement, muscular anatomy, spinal cord reflexes, brain mechanisms, motor behavior, and associated disorders.

What are the two types of muscle fibers found in skeletal muscles?

Extrafusal muscle fibers and intrafusal muscle fibers.

What do extrafusal muscle fibers do?

They are the main working muscle fibers and are contracted by alpha motor neurons.

What do intrafusal muscle fibers detect?

They detect the length of the muscle.

What is the function of Golgi Tendon Organs?

They detect tension on muscles.

What is the role of actin and myosin in muscle contraction?

They slide past each other, resulting in muscle contraction.

What neurotransmitter is released at the neuromuscular junction?

Acetylcholine (ACh).

What is a motor unit?

A motor neuron and the muscle fibers it activates.

What is a monosynaptic stretch reflex?

A reflex that controls limb movements in response to being rapidly stretched.

How does the monosynaptic stretch reflex work?

Sensory afferents from intrafusal muscle fibers synapse on alpha motor neurons that project back to the same muscle.

What characterizes a polysynaptic reflex?

It involves multiple synapses and may inhibit motor neurons through inhibitory interneurons.

What is the role of the primary motor cortex?

It is responsible for causing movements of specific body parts.

Where is the primary motor cortex located?

In the precentral gyrus of the posterior frontal lobe.

What does the term 'somatotopic organization' refer to?

The arrangement of the motor cortex that corresponds to different body parts.

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

It plays a crucial role in planning and sequencing movements.

What happens when the SMA is inhibited?

An individual may execute the first action of a learned sequence but fail to continue.

What is the difference in the functions of the ventromedial and lateral groups of descending pathways?

The ventromedial group controls proximal limb and trunk muscles for balance, while the lateral group controls independent limb movements.

What is the cerebellum primarily responsible for?

Balance, posture, and the timing of rapid movements.

What is the basal ganglia involved in?

The control of movement initiation and inhibition of unwanted movements.

What neurodegenerative disorder is associated with basal ganglia dysfunction?

Parkinson's disease.

What are the three pathways of the basal ganglia?

Direct, indirect, and hyperdirect pathways.

What effect does damage to the lateral zone of the cerebellum have?

It causes disjointed and poorly timed movements.

What is apraxia (dyspraxia)?

Problems with organizing movements in familiar tasks.

What area of the brain is largely implicated in mirror neuron circuitry?

Rostral part of the inferior parietal lobule and the ventral premotor area.

What do mirror neurons respond to?

They activate when an individual engages in or observes a behavior.

What role do neurotransmitters play in the basal ganglia?

Dopamine from the substantia nigra regulates basal ganglia pathways.

What is the consequence of dopamine depletion in Parkinson's disease?

Difficulty initiating movements and resting tremors.

What tasks are affected by lesions in the frontal or parietal lobes?

Tasks requiring the organization of movements, such as drawing or tool use.

What are the two groups of descending motor pathways in the brain?

Lateral group and ventromedial group.

Which muscles do the corticobulbar tract control?

Face and tongue movements.

Which tract is responsible for posture control?

The vestibulospinal tract.

How do cerebellar hemispheres coordinate movements?

They predict the next movement in a sequence for precise timing.

What does the term Golgi tendon organ refer to?

It refers to a sensory receptor that monitors tension within muscles.

What is the primary function of the reticular formation in terms of movement?

It regulates muscle tone and controls specific motor functions.

What does the term 'complex motor behavior' imply?

Behaviors that involve the planning and execution of sequences of movements.

What is an example of complex motor behavior?

Imitating actions observed in others.

What is the primary role of the primary motor cortex?

To initiate voluntary movements.

What area of the motor cortex is engaged for sequential movements?

The motor association cortex.

Where does the rubrospinal tract originate?

From the red nucleus in the midbrain.

What functions are attributed to the cerebellum's lateral zone?

Rapid skilled movements and independent limb control.

What effect does the reticulospinal tract have on muscle tone?

It regulates muscle tone and some reflexes.

Which muscle fibers are activated by gamma motor neurons?

Intrafusal muscle fibers.

What type of muscle movement is primarily controlled by the lateral group?

Independent limb movements like hand and finger motions.

What is the significance of the primary motor homunculus?

It represents the motor control for different body parts in a distorted manner based on their motor control complexity.

How does the Golgi tendon organ contribute to reflexes?

It helps inhibit alpha motor neurons to prevent excessive tension.

What are free nerve endings responsible for in skeletal muscles?

They serve as sensory receptors for pain and temperature.

What is the primary sensory feedback mechanism in muscle contraction?

Intrafusal muscle fibers provide stretch feedback, aiding reflex responses.

How does the structure of skeletal muscle contribute to its function?

Overlapping actin and myosin filaments give skeletal muscle a striated appearance.