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30 Cards in this Set
- Front
- Back
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Nervous system functions |
1. Sensory input 2. Integration 3. Motor Output |
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Divisions of the Nervous system |
1. Central nervous system (CNS) 2. Peripheral nervous system (PNS) |
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Central nervous system |
Brain and spinal cord Integration and control center Interprets sensory input and dictates motor output |
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Peripheral nervous system |
Consists mainly of nerves that extend from brain and spinal cord |
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Functions of PNS |
1. Sensory (afferent) 2. Motor (efferent) |
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Sensory division |
1. Somatic sensory fibers 2. Visceral sensory fibers |
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Somatic sensory fibers |
convey impulses from skin, skeletal muscles and joints to CNS |
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Visceral sensory fibers |
convey impulses from visceral organs to CNS |
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Motor division |
transmits impulses from from CNS to effector organs (muscles and glands) 1. somatic 2. autonomic |
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Somatic nervous system |
somatic motor nerve fibers conducts impulses from CNS to skeletal muscle voluntary nervous sytem |
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Autonomic nervous system |
visceral motor nerve fibers regulates smooth muscle, cardiac muscle and glands involuntary nervous system |
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2 functional subdivisions of autonomic nervous system |
1. sympathetic 2. parasympathetic *work in opposition to each other |
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Neuroglia |
small cells that surround and wrap delicate neurons |
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Neurons (nerve cells) |
large cells that conduct impulses highly specialized high metabolic rate have cell body and one or more processes |
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2 types of neuron processes |
1. dendrites 2. axon |
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Dendrites |
In motor neurons
100s of short, tapering, diffusely branched processes same organelles as in body receptive (input) region of neuron convey incoming messages toward cell body as graded potentials |
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graded potentials |
short distance signals |
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Axon |
one axon per cell conducting region of neuron generates nerve impulses transmits impulses along axolemma to axon terminal |
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Axon hillock |
cone shaped area of cell body "bridge" between cell body and neuron |
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Axon collaterals |
occasional branches, profusely at end can be 10,000 branches |
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Axon terminals/terminal boutons |
distal endings/look like clubs make synaptic contacts with other nerve cells or with effector cells (muscle or gland cells) |
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Axolemma |
the cell membrane surrounding an axon |
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Myelin |
wrapping around axon, whitish protein-lipoid substance, protects/electrically insulates axon, increases speed of nerve impulse transmission |
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Schwann cells |
Any of the cells that cover the nerve fibers in the PNS and form the myelin sheath |
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Nodes of Ranvier |
myelin sheath gaps between adjacent Schwann cells, sites where axon collaterals can emerge |
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3 types of neurons (based on processes) |
1. multipolar 2. bipolar 3. unipolar |
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Multipolar neurons |
3(+) processes 1 axon, others are dendrites most common; major neuron in CNS |
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Bipolar neurons |
2 processes 1 axon, 1 dendrite rare; found in retina |
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Unipolar neurons |
1 short process divides T-like: both branches now considered axons distal (PNS)/proximal (CNS) |
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3 types of neurons (based on direction) |
1. sensory (from sensory receptors toward CNS) 2. motor (carry impulses to CNS) 3. interneurons (in between motor/sensory, shuttle signalsthrough CNS pathways) |
