Chapter 4: Sensorimotor Systems Flashcards
These make up the majority of the human body’s tissues and are responsible for the movement of the body and the movement of materials within the body.
Muscles.
A type of muscle found in the lining of the digestive tract, within arteries, and in the reproductive system; controlled by the autonomic nervous system.
Smooth muscle.
A type of muscle named for its striped appearance; includes cardiac and skeletal muscles.
Striated muscle.
Produces the pumping action of the heart.
Cardiac muscle.
Attached to bones; produces the majority of body movement.
Skeletal muscle.
An individual muscle cell.
Muscle fiber.
The contraction of a single muscle fiber.
Twitch.
A long fiber strand running the length of a muscle fiber that is responsible for contraction.
Myofibril.
A boundary line for each sarcomere within a myofibril.
Z line.
A protein that makes up the thin filaments of the myofibril.
Actin.
A protein that makes up the thick filaments of the myofibril.
Myosin.
In a resting muscle fiber, actin is covered by this protein, which prevents actin from interacting with myosin.
Troponin.
A muscle fiber containing Type I myosin filaments and large numbers of mitochondria that contract slowly using aerobic metabolism; primarily responsible for movement requiring endurance.
Slow-twitch fiber.
A muscle fiber containing Type IIa or Type IIb myosin filaments that contains few mitochondria, uses anaerobic metabolism, and contracts rapidly; primarily responsible for movement requiring explosive strength.
Fast-twitch fiber.
Type IIb fibers can contract up to ___ times faster than Type I fibers.
Ten.
A spinal motor neuron directly responsible for signaling a muscle fiber to contract.
Alpha motor neuron.
A synapse formed between an alpha motor neuron axon terminal and a muscle fiber.
Neuromuscular junction.
Is made up of a single alpha motor neuron and all the muscle fibers it innervates. Includes either fast- or slow-twitch fibers, but not both.
Motor unit.
How do we control muscle contractions?
Method 1: To vary the firing rate of motor neurons.
Method 2: Recruitment - the process of gradually activating more motor units as an increasing load is placed on a muscle.
A sensory structure that provides feedback regarding muscle stretch.
Muscle spindle.
One of the fibers outside the muscle spindle that is responsible for contracting the muscle.
Extrafusal muscle fiber.
A large, fast sensory axon that connects a muscle spindle to neurons in the spinal cord.
Ia sensory fiber.
Tells the intrafusal muscle fibers regarding accurate information about how far the muscle was stretched.
Gamma motor neurons.
A structure located in the tendons of muscles that provides information about muscle contraction.
Golgi tendon organ.
A small, slower sensory axon that connects the Golgi tendon organs to neurons in the spinal cord.
Ib sensory fiber.
It is responsible for a number of reflex movements designed to protect us from injury, to maintain posture, and to coordinate the movement of our limbs.
Spinal cord.
A spinal reflex that requires the action of only one synapse between sensory and motor neurons.
Monosynaptic reflex (Example: Patellar reflex).
A spinal reflex that requires interaction at more than one synapse.
Polysynaptic reflex (Example: catching a ball mid-air).
A polysynaptic spinal reflex that produces withdrawal of a limb from a painful stimulus.
Flexion reflex.
The lateral part of the spinal column; associated with fine motor movements.
Lateral pathway.
Ventromedial part of the spinal column; associated with automatic movements in the neck, torso, and portions of the limbs close to the body (posture).
Ventromedial pathway.
Informs the motor cortex about such factors as the direction, force, and timing required to carry out a skilled movement.
Cerebellum.
Participates in the choice and initiation of voluntary movements.
Basal ganglia.
Motor area located in the gyrus rostral to the precentral gyrus; involved with managing complex sequences of movement.
Supplementary motor area (SMA).
A motor area located in the gyrus rostral to the precentral gyrus; this area participates in holding a motor plan until it can be implemented.
Pre-SMA.
Major Disorders of the Motor Systems.
- Amyotrophic lateral sclerosis (ALS)
- Parkinson’s disease
- Huntington’s disease
- Myasthenia gravis
- Muscular dystrophy
- Polio
- Accidental spinal cord damage
