Chapter 8 - Movement Flashcards
Smooth Muscles
Control the digestive system and other muscles
Skeletal (Striated) Muscles
Control movement of the body in relation to the environment
Cardiac Muscles
The heart muscles; have properties intermediate between smooth & skeletal muscles.
Muscle : Axon Ratio (Eyes, Biceps)
Eyes: (3:1); Biceps (100+:1). Allows the eye to move more precisely than biceps.
Neuromuscular Junction
Synapse between a motor neuron axon and muscle fiber.
What causes a muscle to contract?
Release of acetylcholine in the neuromuscular junction.
What causes a muscle to relax?
Nothing. Muscles relax when there is no message to contract.
Antagonistic Muscles
Opposing sets of muscles which cause arms or legs to move in opposite directions.
Flexor
Muscles that flex the limb. (i.e. at your elbow, it brings your hand toward your shoulder)
Extensor
Muscle that extends a limb. (i.e. at your elbow, it straightens your arm).
Fast-twitch fibers
Muscle fibers that contract quickly, and fatigue rapidly
Slow-twitch fibers
Muscle fibers that contract less vigorously and do not fatigue.
Are slow twitch aerobic or anaerobic?
Aerobic
Aerobic
Use oxygen during movements. Does not cause fatigue of muscles.
Are fast-twitch aerobic or anaerobic?
Anaerobic
Anaerobic
Actions do not require oxygen at the time, but need oxygen for recovery.
Proprioceptor
A receptor that detects the position or movement of a part of the body.
Stretch Reflex
A reflexive contraction of a muscle in response to the stretch of that muscle. DOES NOT PRODUCE a stretch; it is CAUSED by a stretch.
Muscle Spindle
A type of proprioceptor. A receptor parallel to the muscle that responds to a stretch.
Golgi tendon organs
A type of proprioceptor. Respond to increase in muscle tension. Act as brakes against excessively vigorous contractions. Located in the tendons at opposite ends of
Reflexes
Consistent automatic responses to stimuli.
Do we move faster when initiating or responding to stimulus?
We respond
Ballistic Movement
A movement executed as a whole. Once initiated, it cannot be altered. (i.e. reflexes)
Central pattern generators
Neural mechanisms in the spinal cord that generate rhythmic patterns o motor output. “i.e. wing flapping in birds, and the “wet dog shake”). Although stimuli may activate generators, they do not control the frequency.
Motor program
A fixed sequence of movements. (i.e. mouse grooming: sitting up->lick paws->wipe paws over face->close eyes->etc)
Primary Motor Cortex
The precentral gyrus of the frontal cortex which elicits movements.
Posterior Parietal Cortex
Keeps track of the position of the body relative to the world. (i.e. aim, and planning movements)
Supplementary Motor Cortex
Important for planning and organizing a rapid sequence of movements.
Premotor Cortex
Most active immediately before a movement. Processes information about target and information about the body’s current position.
Prefrontal Cortex
Stores sensory information relevant to a movement. Also important for considering probable outcomes of possible movements.
Mirror Neurons
Neurons active during preparation for a movement and while watching someone else perform the same or similar movement.
Readiness potential
Recordable activity in the motor cortex prior to voluntary movement
Corticospinal Tracts
Paths from the cerebral cortext to the spinal cord
Lateral corticospinal tract
Set of axons from the primary motor cortex, surrounding areas, and the red nucleus. Controls movements in peripheral areas (like hands & feet)
Red nucleus
Midbrain area responsible for controlling the arm muscles
Medial corticospinal tract
Axons from many parts of cortex. Axons go to both sides of spinal cord. Controls muscles of the neck, shoulders & trunk, and movements like walking, turning, bending, standing & sitting. Movement includes both sides of tract.
What structure of the brain is responsible mainly for tasks that require timing?
The cerebellum.
Which structure in the brain assists in shifting attention?
The cerebellum
Cerebellar cortex
The surface of the cerebellum
Purkinje cells
Flat cells in sequential planes, parallel to each other
Paralell fibers
Axons parallel to one another (perpendicular to Purkinje cells)
Basal ganglia
Group of large subcortical structures i nthe forebrain. (Caudate nucleus, putamen, globus pallidus). Critical for initiating an action or learning new habits.
Basal ganglia path
Cerebral cortex – > caudate nucleus & putamen –> globus pallidus –> thalamus –> cerebral cortex (motor & prefrontal)
Which brain structure(s) aid in automatic motor responses that are difficult to put in words?
Basal ganglia
Main symptoms of Parkinson’s Disease
Rigidity, muscle tremors, slow movements, and difficulty initiating physical and mental activity.
Population with Parkinson’s
1% - 2% of prople over age 65
Cause of Parkinson’s
Impairment of basal ganglia.
Main treatment for Parkinsons?
L-dopa
L-dopa
Precursor to Parkinson’s which can cross the blood-brain barrier then be converted to dopamine in the brain.
