Lecture 13
Nervous System 1: Histology
62 Cards in this Set
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Human Nervous System
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-Central Nervous System (CNS)
A. Brain
B. Spinal Cord
-Peripheral Nervous System (PNS)
A. Somatic (voluntary)
B. Autonomic (involuntary)
- composed of conducting elements or cells called neurons and accessory elements called neuroglia (supporting cells) and meninges (coverings)
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Neurons
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-responsible for recieving and transmitting information
-classified according to function and structure
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sensory (afferent) neuron
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- neuron that delivers info to CNS
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motor (efferent) neuron
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- neuron that carries info to periphery (ie muscle)
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associative (interneuron) neuron
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- located between sensory and motor neurons
- modifies responses to other neurons
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multipolar neuron
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- multiple processes attached to cell body
- found throughout brain and spinal cord
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bipolar neuron
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- two processes attached to cell body
- found in retina of eye and inner ear
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unipolar neuron
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- one process attached to cell body
- found in ganglia (clusters of neurons adjacent to spinal cord)
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Cell body of a neuron
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contain:
-most of the organelles typically found in cells (ex nucleus, mitochondria, etc)
-nissi bodies
- neurofibrils
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nissi (chromatophilic) bodies
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-clusters of free ribosomes that produce protein (ex neurotransmitters) and rough ER
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neurofibrils
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-represent cytoskeleton of neuron
- helps maintain shape of nerve cell body
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neurofibrils
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-represent cytoskeleton of neuron
- helps maintain shape of nerve cell body
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Dendrite
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-process (fiber) of a neuron
- more than one per neuron
- transmits info into cell body
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Dendrite
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-process (fiber) of a neuron
- more than one per neuron
- transmits info into cell body
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axon (nerve fiber)
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-process (fiber) of a neuron
-only one per neuron
- transmits info from cell body
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axon (nerve fiber)
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-process (fiber) of a neuron
-only one per neuron
- transmits info from cell body
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myelin sheath
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- produced by oligodendrocyte in CNS and by schwann cell in PNS
- composed of lipid
- conducts electrical impulses
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myelin sheath
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- produced by oligodendrocyte in CNS and by schwann cell in PNS
- composed of lipid
- conducts electrical impulses
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neurilemma
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cell wall of oligodendrocyte or schwann cell
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neurilemma
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cell wall of oligodendrocyte or schwann cell
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nodes of ranvier
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bare area - area not covered by myelin
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nodes of ranvier
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bare area - area not covered by myelin
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Types of Neuroglia ("neural-glue")
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in the CNS
-oligodendrocyte
-microglia
-astrocyte (don't forget blood-brain barrier)
-ependymal cells
in the PNS
-schwann cells
-satellite cells
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Types of Neuroglia ("neural-glue")
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in the CNS
-oligodendrocyte
-microglia
-astrocyte (don't forget blood-brain barrier)
-ependymal cells
in the PNS
-schwann cells
-satellite cells
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oligodendrocyte
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-located in CNS
-cells that produce myelin covering around nerve fibers (axons)
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oligodendrocyte
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-located in CNS
-cells that produce myelin covering around nerve fibers (axons)
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microglia
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-located in CNS
-phagocytic cells of CNS
-ingests dead or damaged tissue
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microglia
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-located in CNS
-phagocytic cells of CNS
-ingests dead or damaged tissue
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astrocyte
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-located in CNS
-cells that assist in the nourishment of neurons in the CNS
-helps form "blood-brain barrier"
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astrocyte
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-located in CNS
-cells that assist in the nourishment of neurons in the CNS
-helps form "blood-brain barrier"
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blood-brain barrier
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-formed by astrocyte
-regulates what substances pass from bloodstream into CNS
-composed of:
1)astrocyte
2)basement membrane
3)endothelial wall of capillary
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blood-brain barrier
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-formed by astrocyte
-regulates what substances pass from bloodstream into CNS
-composed of:
1)astrocyte
2)basement membrane
3)endothelial wall of capillary
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ependymal cells
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-located in CNS
-cells that line the cavities of ventricles of the brain
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ependymal cells
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-located in CNS
-cells that line the cavities of ventricles of the brain
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schwann cells (neurolemmocytes)
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-located in PNS
-produce myelin covering around nerve fibers (axons) in PNS
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schwann cells (neurolemmocytes)
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-located in PNS
-produce myelin covering around nerve fibers (axons) in PNS
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satellite cells
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-located in PNS
-regulate nourishment to neurons in PNS
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satellite cells
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-located in PNS
-regulate nourishment to neurons in PNS
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nuclei
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cluster of neurons in CNS
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nuclei
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cluster of neurons in CNS
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ganglia (ganglion)
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cluster of neurons in the PNS
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ganglia (ganglion)
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cluster of neurons in the PNS
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nerve
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bundles of axons in PNS
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nerve
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bundles of axons in PNS
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tract
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bundles of axons in CNS
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tract
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bundles of axons in CNS
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synapse
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-site of communication between neurons
-located in synaptic cleft (space) between them
-composed of:
-pre synaptic neuron
-synaptic cleft
-post synaptic neuron
-neurotransmitter in a pre synaptic axon is released across a synapse to attach to receptor sites on dendrite of post syna…
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synapse
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-site of communication between neurons
-located in synaptic cleft (space) between them
-composed of:
-pre synaptic neuron
-synaptic cleft
-post synaptic neuron
-neurotransmitter in a pre synaptic axon is released across a synapse to attach to receptor sites on dendrite of post syna…
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conduction of nerve impulse
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electrical impulse causes change of permeability of membrane
causes NA+ on outside to move inside
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conduction of nerve impulse
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electrical impulse causes change of permeability of membrane
causes NA+ on outside to move inside
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Continuous Conduction vs. Saltatory Conduction
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Continuous - impulse travels in continuous flow along an axon
Saltatory - impulse jumps or is transmitted from node of of ranvier to another
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Continuous Conduction vs. Saltatory Conduction
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Continuous - impulse travels in continuous flow along an axon
Saltatory - impulse jumps or is transmitted from node of of ranvier to another
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A-fibers
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-most heavily myelinated
-produces sharp pain
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A-fibers
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-most heavily myelinated
-produces sharp pain
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B-fibers
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-intermediate amount of myelin
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B-fibers
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-intermediate amount of myelin
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C-fibers
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-least amount of myelin, no myelin in some cases
-produces dull pain
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C-fibers
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-least amount of myelin, no myelin in some cases
-produces dull pain
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excitatory neurotransmitters
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- cause deploration of the postsynaptic neuron
1. acetylcholine
2. norepinephrine
3. serotonin
4. dopamine
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excitatory neurotransmitters
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- cause deploration of the postsynaptic neuron
1. acetylcholine
2. norepinephrine
3. serotonin
4. dopamine
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inhibatory neurotransmitters
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-hyperpolarize the postsynaptic neuron preventing the transmission of the nerve impulse across the synapse
1. GABA - inhibits cerebellum
2. enkephalins -
effects mimicked by heroin and morphine
3. endorphins -
4. dopamine - found in automatic nerve s…
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inhibatory neurotransmitters
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-hyperpolarize the postsynaptic neuron preventing the transmission of the nerve impulse across the synapse
1. GABA - inhibits cerebellum
2. enkephalins -
effects mimicked by heroin and morphine
3. endorphins -
4. dopamine - found in automatic nerve s…
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Lecture 13