Muscle Types and Movement Control

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Questions and Answers

What are the 3 categories of muscles?

Smooth Muscles (correct)

Skeletal/Striated Muscles (correct)

Cardiac Muscles (correct)

All of the above

What is it called when skeletal muscles can be fast or slow?

Fast-twitch or Slow-twitch

The Golgi Tendon Organ is located in the muscles.

False

What are reflexes?

Involuntary, consistent, and automatic responses to stimuli. Signup and view all the answers

What is a monosynaptic Reflex?

Reflex requiring one synapse between sensory input and movement. Signup and view all the answers

What is a central pattern generator?

A neural mechanism in the spinal cord or elsewhere that generates rhythmic patterns of motor output. Signup and view all the answers

What is the role of the prefrontal cortex?

Plans complex behaviour Signup and view all the answers

What is a brain-computer interface (BCI)?

Uses the brain's signals to direct computer-controlled devices (eg. neuroprosthetics) Signup and view all the answers

What is the role of the cerebral cortex?

Initiating a motor sequence Signup and view all the answers

What does the medial tract control?

The muscles of the neck, shoulders, and trunk Signup and view all the answers

What is the role of the brainstem in movement?

Maintaining posture, standing upright, coordinating movements of the limbs, swimming and walking, grooming the fur, and making nests. Signup and view all the answers

What is the cerebellum associated with and how many neurons are there?

Balance and coordination. More neurons in the cerebellum than in all other brain areas combined. Signup and view all the answers

What does damage to the cerebellum cause?

Trouble with rapid movements requiring aim / timing. e.g., clapping hands, speaking, writing. Signup and view all the answers

What is the basal ganglia?

A group of large subcortical structures in the forebrain Signup and view all the answers

What is the basal ganglia responsible for?

Initiating an action not guided by a stimulus. Signup and view all the answers

What is the basal ganglia comprised of?

Caudate Nucleus Putamen Globus Pallidus Signup and view all the answers

What are the pathways for Input and Output of the Basal Ganglia?

Input Cerebral Cortex → Caudate Nucleus and putamen → Globus Pallidus Output Globus Pallidus → Thalamus → Motor areas and the prefrontal cortex. Signup and view all the answers

How does a basal ganglia select a movement?

By ceasing to inhibit it. Signup and view all the answers

What happens when new skills are learned?

The pattern of activity of the neurons in the motor cortex becomes more consistent. Signup and view all the answers

What happens with conscious decisions and movement?

It happens at two different times Signup and view all the answers

What is a readiness potential?

Activity in the motor cortex that occurs before voluntary movement Signup and view all the answers

What are movement disorders?

Brain disorders, such as parkinson's disease and Huntington's disease not only affect movement, but also impair mood, memory, and cognition. Signup and view all the answers

What are the movement symptoms of Parkinson's Disease? (Select all that apply)

Rigidity Signup and view all the answers

What are the symptoms of parkinsons?

Muscle tremors, rigidity, slow movements, difficulty initiating physical and mental activity, depression, memory and reasoning deficits, loss of olfaction, other cognitive deficits Signup and view all the answers

What causes Parkinsons?

Gradual and progressive death of neurons, especially in the substantia nigra Signup and view all the answers

What does the substantia nigra do?

It usually sends dopamine releasing axons to the caudate nucleus and putamen Signup and view all the answers

How does loss of dopamine affect the motor cortex?

Leads to less stimulation of the motor cortex and slower onset of movements Signup and view all the answers

What is the treatment for Parkinson's?

The drug L-dopa is a precursor to dopamine that easily crosses the blood-brain barrier Signup and view all the answers

What are other treatments for Parkinsons?

Drugs that directly stimulate dopamine receptors, implanting electrodes to stimulate areas deep in the brain, experimental: stem cell Signup and view all the answers

What is Huntington's Disease?

A neurological disorder characterized by carious motors symptoms. Affects 1 in 7,000 in Canada Usually onset occurs between age 30-50 Signup and view all the answers

What are the physical symptoms of Huntington's disease? (Select all that apply)

Involuntary movements (chorea) Signup and view all the answers

What are the cognitive symptoms of Huntington's disease? (Select all that apply)

Difficulty with focus Signup and view all the answers

What are the emotional symptoms of Huntington's disease? (Select all that apply)

Depression Signup and view all the answers

What are presymptomatic tests?

Can identify with high accuracy who will develop the disease Signup and view all the answers

What controls hereditary diseases?

Controlled by an autosomal dominant gene on the chromosome #4 Signup and view all the answers

What is the likelihood of getting a disease?

The higher the number of consecutive repeats of the combination C-A-G = the more certain and earlier the person is to develop the disease. Signup and view all the answers

Study Notes

Movement

Three categories of muscles: Smooth, Skeletal/Striated, and Cardiac.
Smooth muscles control digestive and internal organs.
Skeletal muscles control voluntary movements.
Cardiac muscles control the heart.
Muscle fibers receive information from a motor neuron axon.
A neuromuscular junction is a synapse between a motor neuron axon and a muscle fiber.
Acetylcholine causes muscle contraction.
Antagonistic muscles work in pairs to produce movement.
Flexors bend a joint; Extensors straighten a joint.
Fast-twitch muscle fibers contract quickly but fatigue rapidly.
Slow-twitch muscle fibers contract more slowly but do not fatigue easily.
Proprioceptors are receptors that detect the position and movement of body parts.
Muscle spindles and Golgi tendon organs are types of proprioceptors.

Reflexes and Movement Control

Reflexes are involuntary, consistent, and automatic responses to stimuli.
Monosynaptic reflexes involve one synapse.
Movements can be reflexive or voluntary.
A central pattern generator generates rhythmic movement patterns.
A motor program is a learned or built-in sequence of movements.
A brain-computer interface uses brain signals to control devices.
Major components of motor system include the Cerebrum (forebrain), brainstem, and spinal cord.
The cerebral cortex plans and executes complex behaviors.
The prefrontal cortex plans movements.
The premotor cortex produces movement sequences.
The primary motor cortex controls specific areas of the body.

The Brain and Movement

The primary motor cortex is involved in movement.
The somatosensory cortex plays a role in the primary motor cortex.
The posterior parietal cortex plans movements.
Anti-saccade tasks inhibit movements.
Mirror neurons may be involved in imitation and understanding of actions.

Spinal Cord and Tracts

The corticospinal tracts are pathways between the brain and spinal cord.
The lateral corticospinal tract controls peripheral areas like hands and feet..
The medial corticospinal tract controls trunk and neck muscles.
The red nucleus and vestibular nucleus are involved in motor control.

Brain Stem and Movement

The brainstem helps maintain posture and coordinates bilateral body movements.
The brainstem is involved in movement, posture, and balance.

Disorders

Locked-in syndrome: a condition of complete paralysis except for eye movements.
Spinal cord damage can result in quadriplegia or paraplegia, causing paralysis and loss of sensation.
Spinal reflexes are still possible after spinal cord injury.
Various disorders such as Paralysis, Quadriplegia, Hemiplegia, Tabes Dorsalis, Poliomyelitis or Amyotrophic lateral sclerosis affect movement.

Huntington's Disease

Huntington's disease is a neurological disorder characterized by motor symptoms, cognitive decline, and emotional disturbances.
It affects approximately 1 in 7000 individuals in Canada and typically emerges between ages 30 to 50.
Symptoms involve involuntary movements (chorea), cognitive problems, and emotional changes.
Presymptomatic testing and genetic screening can identify those at risk of acquiring Huntington's.
The disease is hereditary and is linked to a specific genetic mutation.
It is progressive and ultimately fatal.

The Cerebellum

The cerebellum plays a crucial role in balance, coordination, and precise control of movement.
Damage to the cerebellum results in problems with rapid movements, timing, and coordination.
The cerebellum receives information about intended movements and actual movements to calculate errors and correct movement sequences.
The finger-to-nose test can be used to assess cerebellar function.

Basal Ganglia

The basal ganglia are a group of subcortical structures involved in initiating and coordinating movement.
Damage to the basal ganglia can cause involuntary movements or difficulties with initiating voluntary movements.
Basal ganglia are responsible for selecting and initiating voluntary movements and inhibiting unwanted movements.

Parkinson's Disease

Parkinson's is a movement disorder characterized by difficulties initiating, controlling, and coordinating movement.
It's caused by neuronal death in the substantia nigra, which normally produces dopamine.
Dopamine is critical for smooth, uncontrolled movements,
Parkinsons symptoms include tremors, rigidity, slowness of movement, balance and posture problems.
Treatments include medication such as L-dopa and other therapies.

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Description

Explore the fascinating world of muscles and movement through this quiz. Learn about the three main types of muscles: smooth, skeletal, and cardiac, as well as the mechanisms of muscle contraction and reflexes. Test your knowledge on how muscles work together to enable movement and control.