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P 226 ch. 7 physiology

Terms in this set (32)

Neurons/ nerve cells
Highly specialized to transmit messages from one part of the body to another
Cell body
The metabolic center of the neuron
Nissl substance and neurofiberils
Intermediate filaments that are important in maintains cell shape and are abundant in the cell body
Processes or fibers
Vary in length from microscopic to 3 to 4 feet.
Dendrites
Neuron processes that convey incoming messages toward the cell body
Axons
Those that generate nerve impulses and conduct them away from the cell body
Axon hillock
Each neuron arises from s conelike region of the cell body called
Axon terminals
An occasional axon gives off a collateral branch along its length, but all axon branch profusely at their terminal end, forming hundreds and thousands of
Neurotransmitters
Terminals contain hundred of tiny vesicles or membranous sacs that contain chemicals called
Synaptic cleft
Each axon terminal is separated from the next neuron by a tiny gap called
Synapse
A functional junctiion
Myelin
Most long nerve fibers are covered with a whitish fatty material called
Schwann cells
Specialized supporting cells that wrap themselves tightly around the axon jelly roll fasion
Myelin sheath
A tight coil wrapped membrane Encloses the axon after the wrapping prices is done
Neurilemma
The part of the Schwann cell external to the myelin sheath is called the
Nodes of ranvier
Since the myelin sheath is formed by many individual Schwann cells, it has gaps or indentations called
Three major functions of the nervous system
Sensory integration and motor
Sensory
Monitors internal and external environment through presence of receptors
Integration
Interpretation of sensory information, complex function
Motor
Response to information processed through stimulation of effectors
CNS
Nervous system subdivision that is composed of the brain and spinal cord
Somatic NS
Subdivision of the PNS that controlled voluntary activity such as activation of the skeletal muscles
Automic NS
Subdivision of PNS that regulates heat and smooth muscle and glands
CNs
A major subdivision of the nervous system that inturprets incoming information and issues order
PNS
A major subdivision of the nervous system that serves as communication lines, linking all parts of the body to the CNS
Involuntary nervous system
2 parts sympathetic and parasympathetic
Motor or efferent division
Carries impulses from the CNS to effector organs, the muscles, and glands
Sensory fibers
Deliver impulses from the skin, skeletal muscle, and joints called somatic sensory fibers
Sensory or afferent division
Consist of nerve fibers that covet impulses to the central nervous system from sensory receptors located in various parts of the body
Spinal nerves
Carry impulses to and from the spinal cord
Cranial nerves
Carry impulse to and from the brain
Two great controlling systems of the body are
Endocrine and nervous system
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