NRSC 2100: EXAM 1
30 Cards in this Set
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Types of Glial Cells
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Oligodendrocytes, Schwann Cells, Astrocytes, Microglia, Ependymal Cells
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Oligodendrocyte
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Create myelin sheaths for multiple axons within the CNS
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Schwann Cell
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Creates myelin sheaths for single axons in the PNS
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Astrocytes
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Provides nutrients and oxygen to neurons (at Blood-Brain Barrier), regulates concentration of K+, removes waste products
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Microglia
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act as phagocytes, cleans up waste and dying cells/cell debris
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Ependymal Cells
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Lines the ventricles and other cavities in the brain, also might make Cerebrospinal fluid
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Egyptian Beliefs
(2500-600 BC)
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Thought the heart to be the seat of the soul. Did not consider the brain to be important at all
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Greek Beliefs
(500-200 BC)
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Hippocrates- Believed the brain to be an organ of sensation and the seat of intelligence
Aristotle- believed the heart to be the seat of intelligence and that the brain was just a cooling unit for blood
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Roman Era
(0-200 AD)
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Galen- named major nerves in the brain, supported Hippocrates' views, differentiated between cerebellum (for muscle control) and cerebrum (for the senses)
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Early Renaissance Era (c. 1500)
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Janssen- invented compound microscope (~1663)
Hooke- discovered cells by looking at cork slices
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Bell and Megandie (1810)
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Identified distinction between motor and sensory neurons, also that they are often bundled together
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Gall (1827)
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developed notion of phrenology, believed size of brain regions correlates to certain functions
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Flourens (1823)
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believed mental function to be equally localized
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Broca (1861)
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provided evidence that certain functions *are* localized (Broca's area, for producing organized speech)
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Pre-Civilized Humans (~7000 BC)
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performed trepenation to cure symptoms, obviously thought brain to be of some importance
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Basic Structure of a Neuron
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1) cell body (called soma or perikaryon)
2) dendrites and dendritic spines
3) Axon
4)Myelin Sheaths
5) Nodes of Ranvier
6) Axon Terminals
7) Axon Hillock
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Cellular Components of a Neuron
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Cell membrane, cytoplasm, nucleus, ribosomes and Rough ER, Golgi Apparatus, Mitochondria, Smooth ER,
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Microtubules
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~20 nm, made of tubulin, regulated by “tau”. Provides structure to axon-- not in axon terminals
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Neurofilament
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~10 nm, made of actin, attaches to cell membrane
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Microfilament
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~5 nm, made of actin, wraps up in strands of polymers like a rope- protein transport
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Axon Hillock
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takes incoming signals and integrates them. If a threshold is reached, the cell fires an action potential down the axon
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Axon
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a long myelinated strand that conducts an electrical signal down to the axon terminals (the pre-synaptic component)
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Axoplasmic Transport
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Antereograde- kinesin carries vesicles away from soma
Retrograde- dynein travels up towards soma, informs of metabolic changes
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Electrical Synapse
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Allows for direct ion transfer through Gap Junction. Gap Junctions are made up of two "connexons", each of which are made up of three "connexins"
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Chemical Synapse
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Chemicals (neurotransmitters) are released by vesicles into synaptic cleft, which bind to protein receptors in post-synaptic membrane
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Types of Chemical synapes based on Connection
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Axo-dendritic,
Axo-sematic,
Axo-axonic
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Types of chemical synapses based on Neurotransmitter
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Excitatory synapse (glutamate, aspartate)
Inhibitory Synapse (GABA, glycine)
Modulatory Synapse (Adrenergic, such as dopamine and adrenaline)
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Forces that Act upon Ion concentration
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Diffusion- ions move down concentration gradient to reach equilibrium
Electrical Forces- like-repels-like, positive ions will repel one another until equilibrium is reached
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Depolarization
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inside of neuron becomes less negative. Na+ ions flow into cell
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Hyperpolarization
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Inside of cell becomes more negative. Cl- ions flow in, or K+ ions flow out of cell
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NRSC 2100: EXAM 1