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What makes up the CNS?
Brain & Spinal Cord
What makes up the PNS?
-Crainial nerves (12 Pairs)
-Spinal nerves(31 pairs)
-Perifpheral nervers (numerous)
What comprises the nervous system?
Brain, spinal cord, spinal nerves, ganglia, enteric plexuses, and sensory receptors.
What is the function of a sensory receptor?
detect changes in the internal or external environment.
What carries a signal from a receptor to the brain and spinal cord?
Sensory neurons (afferent neurons)
What is the function of an integrative neuron?
-analyze, and store info
-make decisions
-Many are interneurons (short ones in the brain, spinal cord, and ganglia that connect nearby nearons)
What is a motor neuron?
-respond to decisions
-carry information from the brain and spinal cord to the muscles or glands
-an efferent neuron
What are the 3 levels of organization of the nervous system?
What is Somatic?
-sensation from the body wall, limbs, head, special senses (sight, hearing, taste, balance, smell.)
-motor control of skeletal muscles(voluntary)
What is Autonomic?
-sensation from internal organs like heart, lungs, bladder.
-motor control of smooth and cardiac muscle, as well as glands.
what is enteric nervous tissue?
-sensation from gastrointestinal tract
-motor control of smooth muscle and glands of the GI tract
The motor portion of the autonomic nervous system consists of?
What is a nerve?
an association (bundle) of neuronal axons in the peripheral nervous system. (includes associated dendrites and other tissues)
What is a ganglion?
a group of neuronal cell bodies in the peripheral nervous system (plus associated tissues)
What is a tract?
an association (bundle) of neuronal axons in the CNS
What is a nucleus?
an association (bundle) of unmyelinated nerve cell bodies in the CNS.
What is a plexus?
-a network of nerves.
-can also mean a network of veins or lymphatic vessels.
What are the cells of the nervous system?
Neurons and Neuroglia
What is a neuron?
cells that possess electrical excitability.  Cells which do the things that are thought of as nervous system function.(sensing thinking, etc.)
What are Neuroglia?
cells of the nervous system that support, nourish, and protect the neurons.
What is the more numerous nervous system cell?
neuoglia outnumber the neurons.
what is the basic structure of a neuron?
-cell body
-nerve fibers comprising an axon and dendrites

what are prominent clusters of rough ER of a neuron?
Nissl bodies
what is axoplasm?
the cytoplasm of an axon
what is an axolemma?
the plasmalemma of an axon
what are dendrites?
the receiving portion of a neuron
-short tapering highly  branched
-"little trees"
what is an axon?
a nerve fiber that propagates impulses to another neuron, muscle or nerve.
-can be 3 ft long in humans
how many axons per neuron?
almost always 1
what is an axon hillock?
- a small hill
- an elevation in the cell body
what does the axon contain?
does protein synthesis occur in the axon?
No, there is no Rough ER.
what is lipofuscin?
-a yellow brown pigment that occurs as granular clumps in the cytoplasm of neurons.
-made by neuronal lysosomes
-accumulates with age
what makes up the cytoskeleton of a neuron?
neurofibrils & microtubules
What are neurofibrils?
-intermediate filaments that provide the cell shape
-extends into the axon and dentrites.
What is the function of a microtubule?
participate in moving material between the body and axon.
-made of tubulin.
Describe axonal terminals?
contain only some cytosol, mitochondria, cytoskeleton, Smooth ER, and synaptic vesicles.
where are  new proteins for the axon terminal produced?
in the cell body.
How are new proteins moved from the cell body to the axon terminal?
by slow or fast axonal transport.
Descrobe slow axonal transport.
-1-5 mm per day
-one way (cell to terminal)
-transports axoplasms to growing or regenerating axons.
Descrobe Fast axonal transport.
-200-400 mm per day
-Two way transport
-uses microtubules as tracks and motors.
-transports organelles and meterials that are used to form axolemma membranes, synaptic end bulbs and synaptic vesicles.
what are the 3 types of neurons?
-unipolar (psudounipolar)
Describe a Multipolar neuron.
-the "type" neuron
-brain and spinal cord motor neurons
-several short dendrites
-1 axon
describe bipolar neurons.
-special sensory organs
-1 main dendrite
-1 axon
describe unipolar neurons
-typical sensory neuron
-axon and dendrite are fused for a short distance then split
-peripheral process: receptors with dendrites at distal end carries impulse toward cell body
-central process: carries impulses toward the CNS
What are neuroglia?
-not exciteable cells
-small and more numerous than neurons
-play a supporting role
-compose 1/2 the volume of CNS
-fill in spaces of neurons during injury or disease.
What are the types of neuroglia in the CNS?
-Ependymal cells
what are the types of neuroglia in the PNS?
-Schwann cells (neurolemmocytes)
-Satellite cells
What is the function of astrocytes?
regulate the composition of the ECF in the CNS; help form the blood brain barrier.
what is the function of an Oligodendrocyte?
myelinate axons in the CNS
what is the function of Microglia?
phagocytes of the CNS
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