Neuromotor Basis of Movement

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Terms in this set (...)

Neuromotor System
components of the central nervous system (CNS) and peripheral nervous system (PNS) involved in the control of coordinated movement
-focus of current section is CNS structure and function
Central Nervous System
-brain
-spinal cord
Brain
receives and processes sensory information, initiates responses, stores, memories generates thoughts and emotions
Spinal Cord
conducts signals to and from the brain, controls reflex activities
Motor Neurons
CNS to muscles and glands
Sensory Neurons
sensory organs to CNS
Somatic Nervous System
controls voluntary movements
Autonomic Nervous System
controls involuntary responses
Sympathetic Division
"fight or flight"
Parasympathetic Division
"rest or digest"
Neuron
-nerve cell
-basic component of the nervous system
-range in size from 4 to 100 microns
Cell Body
contains nucleus
Dendrites
-extensions from cell body: range from 0 to 1000 per neuron
-receive information from other cells
Axon
-"nerve fiber"
-extension from cell body - one per neuron with branches (known as collaterals)
-sends information from neuron
Information Flow Through Neurons
-dendrites collect electrical signals
-cell body integrates incoming signals and generates outgoing signal to axon
-axon passes electrical signals to dendrites of another cell or to an effector cell
Sensory Neurons
"afferent" neurons
-send information to CNS from sensory receptors
-unipolar - 1 axon; no dendrites
-cell body and most of the axon located in PNS; only axon central process enters CNS
Motor Neurons
"efferent" neurons
-alpha motor neurons: predominantly in spinal cord - axons synapse on skeletal muscles
-gama motor neurons: in intrafusal fibers of skeletal muscles
Interneurons
Specialized neurons that originate and terminate in the brain or spinal cord.
Interneurons: Function as connections between
-axons from the brain and motor neurons
-axons from sensory nerves and the spinal nerves ascending to the brain
-it is estimated that the human brain contains 100 billion (10^11) interneurons averaging 1000 synapses on each; that is, some 10^14 connections
Structures: Control of Voluntary Movement
-cerebrum
-diencephalon
-cerebellum
-brainstem
Cerebrum
One of two components of Forebrain.
-two halves: right and left cerebral hemisphere (connected by the corpus callousum)
-covered by cerebral cortex
-gray tissue; 2 - 5-mm thick
-undulating covering of ridges and grooves