Dystonia: A Neurological Disorder

Explanation
Dystonia is a neurological disorder characterized by involuntary muscle contractions that cause repetitive or twisting movements. Skeletal muscles are responsible for voluntary movements and are under conscious control, making them the most likely muscle type to be affected by dystonia. Cardiac muscles are found in the heart and smooth muscles are found in the internal organs, therefore they are not typically associated with dystonia.

Explanation
Dystonia is a movement disorder characterized by involuntary muscle contractions that cause repetitive or twisting movements. It can be classified into different types based on the distribution of muscle involvement. Focal dystonia refers to dystonia that affects only one part of the body, while segmental dystonia involves two or more adjacent body regions. Generalized dystonia affects multiple body regions, and polysegmented dystonia is not a recognized classification of dystonia.

Explanation
Graded potentials are actually slower changes in membrane potential that can be caused by various stimuli, such as neurotransmitters or sensory input. They can either be depolarizing (bringing the membrane potential closer to the threshold for an action potential) or hyperpolarizing (moving the membrane potential further away from the threshold). Action potentials, on the other hand, are brief, rapid, and all-or-nothing changes in membrane potential that are triggered by a graded potential reaching the threshold. Therefore, the statement that graded potentials are activated by action potentials is incorrect.

Explanation
Cervical dystonia is a condition that primarily affects the neck muscles, causing involuntary contractions and abnormal postures. This can result in twisting or turning of the neck, causing pain and discomfort. While the other body areas mentioned may be affected by other conditions, cervical dystonia specifically targets the neck area.

Explanation
Botulinum toxin is a neurotoxin that is commonly used to treat dystonic symptoms. Dystonia is a movement disorder characterized by involuntary muscle contractions, which can cause abnormal postures or repetitive movements. Botulinum toxin works by blocking the release of acetylcholine, a neurotransmitter that signals muscle contraction. By injecting botulinum toxin into specific muscles, it can temporarily weaken or paralyze them, reducing the dystonic symptoms and improving the patient's quality of life. Therefore, the statement "Botulinum toxin is used to treat dystonic symptoms" is true.

Explanation
During excitation-contraction coupling, an action potential triggers the release of calcium ions into the sarcoplasm. These calcium ions bind to troponin, causing a conformational change that allows the myosin heads to bind to actin and initiate muscle contraction. Therefore, the correct answer is calcium.

Explanation
The gene that has been discovered for torsion dystonia is DYT1.

Explanation
The basal ganglia is a group of structures located deep within the brain that play a crucial role in the initiation and coordination of voluntary movements. It receives input from various parts of the brain, including the cerebral cortex, and sends signals to the motor cortex to initiate muscle contractions. Therefore, it can be inferred that the basal ganglia is responsible for processing the initial muscular contractions. The pons, thalamus, and amygdala are not directly involved in motor control and do not play a significant role in processing initial muscular contractions.

Explanation
Dystonia is a neurological movement disorder that causes involuntary muscle contractions, resulting in abnormal movements or postures. However, it does not directly affect intelligence. Intelligence is a separate cognitive ability related to learning, problem-solving, and reasoning skills. While dystonia may have an impact on a person's quality of life and ability to perform certain tasks, it does not affect their intelligence. Therefore, the statement that dystonia affects the intelligence of those with the disorder is false.

Explanation
Fatigue often triggers dystonic movements. Dystonia is a movement disorder characterized by involuntary muscle contractions that cause repetitive or twisting movements. When a person is fatigued, their muscles become tired and may not function properly, leading to dystonic movements. This can be seen in conditions such as task-specific dystonia, where repetitive movements or prolonged use of specific muscles can result in fatigue and trigger dystonic symptoms. Therefore, fatigue is a common trigger for dystonic movements.