Motor Functions Flashcards
Reflex
Unlearned response to a particular stimulus
Motor Plan
A complex set of commands to muscles that is established before the behavior starts
Closed-Loop Control Mechanism
Maximize accuracy
Information from whatever is being controlled flows back to the device that controls it
Transducer
An element that measures output
Error Detector
Measures difference between actual and desired output
Open-Loop Control Mechanisms
Maximize speed
Activity is preprogrammed
Smooth Muscles
A type of muscle fiber that is controlled by the autonomic nervous system rather than by voluntary control
Antagonist Muscle
A muscle that counteracts the effect of another muscle
Synergist Muscle
A muscle that acts together with another muscle
Muscle Fibers
Work together under voluntary control
Fast-Twitch Muscle Fibers
Contracts rapidly but fatigues easily (Legs)
Slow-Twitch Muscle Fibers
Contracts slowly but does not fatigue easily
Neuromuscular Junction
The region where the motor neuron terminal and adjoining muscle fiber meet
The point where the nerve transmits its message to the muscle fiber
Innervation Ratio
Expresses the number of muscle fibers innervated by a single motor axon
Proprioception
Body Sense
Information about the position and movement of the body that is sent to the brain
Muscle Spindle
Sends impulses to the central nervous system when the muscle is stretched.
Intrafusal Fiber
Small muscle fibers that lie within each spindle
Extrafusal Fiber
One of the ordinary muscle fibers that lie outside the spindles and provide most of the force for muscle constriction
Primary Sensory Ending
The axon that transmits information from the central portion of a muscle spindle
Secondary Sensory Ending
The axon that transmits information form the ends of the muscle spindle
Gamma Motor Neurons
Innervates the contractile tissue in a muscle spindle
Alpha Motor Neurons
Controls the main contractile fibers (extrafusal fibers) of a muscle
Stretch Reflex
- Weight is added
- The muscle is stretched
- Afferents from the muscle spindle are excited
- The spindle afferents connect directly to the motorneurons that control the stretched muscle, exciting them
- The motorneurons stimulate the muscle to oppose muscle stretch
Central Pattern Generator
Responsible for generating the rhythmic pattern of a behavior such as walking
The Pyramidal System
Brain uses this system to send commands through the spinal cord
Dystrophin
A protein needed for normal muscle function
Ideomotor Apraxia
The inability to carry out a simple motor activity in response to a verbal command, even though this same activity is readily performed spontaneously
Ideational Apraxia
An impalment in the ability to carry out a sequence of actions, even though each element and step can be done correctly
