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Definition
| brain, spinal cord, and parts of the eye; made of neurons and glia |
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Term
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Definition
| peripheral ganglia, nerve and nerve endings and receptors; cells include neurons, satellite cells, and Schwann cell |
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Term
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Definition
| 1. cell body containing a nucleus; 2. dendrites bring impulses towards cell body; 3. axon carries impulse away from cell body |
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Definition
| terminal arborization of the axon and each terminal branch has a enlarged ending (synaptic terminal or bouton) |
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Term
| development of neural tissue |
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Definition
| 1. appears at the end of third week of development as thickened ectoderm known as neural plate; 2. edges of plate fold up and form neural tube; 3. cranial dilation will form portions of the brain; 4. wall of neural tube forms neuroepithelium which differentiate to neuroblasts and give rise to neurons and gray matter of spinal cord |
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Definition
| specialized region of neural plate that seperates from to tube to give rise to the PNS |
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Definition
| junction between end of an axon terminal and another axon, dedrite, or somatic cell |
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| transmitting side of neuron |
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Definition
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Term
| characteristics of neural cell body |
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Definition
| 1. large nucleus with dispersed euchromatin and prominent nucleolus; 2. abundant ribosomes and free and RER; 3. neurotubules and neurofilaments; |
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Term
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Definition
| 1. arises from soma from region called "axon hillock"; 2. diameter uniform throughout |
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Term
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Definition
| under LM, what is stained as free of bound ribosomes to ER (not located in the axon hillock) |
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Definition
| area found between neural cell bodies; has packed dendrites, axonal branches, and glial cells |
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Definition
| functionally and structurally related neurons that form aggregates in the CNS |
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Term
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Definition
| cluster of neurons in the PNS, may be sensory or motor |
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Definition
| many processes, only single axon and many dendrites projecting from the cell body (intermediate, integratory, and motor neurons) |
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Definition
| single dendrite and single axon; act as receptors for smell, sight, and balance |
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Term
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Definition
| primary sensory neurons with a single dendrite and axon arising from common stem of the cell body; stem formed byy fusion of the first part of dendrite and axon of bipolar type of neuron during development (sensory ganglia of cranial and spinal nerves) |
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Term
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Definition
| vast majority of axonal proteins synthesized in cell body and then delivered to the axon |
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Term
| anterograde axonal transport |
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Definition
| occurs by kinesin and occurs along MT in the + direction |
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Term
| retrograde axonal transport |
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Definition
| occurs by dynein along microtubules towards the - direction |
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Term
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Definition
| enters and replicates in muscle cells; binds to acetycholine receptors and mobilized by retrograde axonal transport to cell body of neurons supplying the muscle; replicates and disseminates throughout the CNS; from here transported to salivary glands from CNS |
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Term
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Definition
| synapses that have axon terminals facing a dendritic spine |
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Term
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Definition
| axon terminals are on the shaft of a dendrite |
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Term
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Definition
| axon terminals are on the soma of neuron |
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Term
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Definition
| axon terminals are ending on axon terminals |
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Term
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Definition
| rigid structure with pre and post synaptic ends may be supported by bridges between membranes; axon end in terminal buton (not myelinated w/ mitochondria and synaptic vesicles) |
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Term
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Definition
| hold chemical messengers in the pre-synaptic neuron ; have vescular docking proteins on them that attach to membrane docking proteins |
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Term
| chemical synaptic transmission |
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Definition
| 1. axon terminal becomes depolarized and causes influx of calcium; 2. influx of calcium induces exocytosis of synaptic vesicles; 3. chemical messenger released into the synaptic cleft and binds to receptor of postsynaptic membrane to transmit information; 4. chemical messenger enzymatically degraded or taken up by endocytosis and degraded by monoamine oxidase |
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Definition
| carries conscious sensations and innervates voluntary muscle of the body |
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Definition
| motor and controls involuntary visceral activities of the body; parasympathetic and sympathetic |
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Term
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Definition
| light-staining H-shaped area where neuron cell bodies and glial cells are found |
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Term
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Definition
| made up of glial cells and blue-staining myelin aroound axons in dark staining area; surrounds the gray matter |
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Term
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Definition
| bundles of axons in the CNS (fasciculi) |
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Term
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Definition
| surround neuronal cell body and axonal and dedritic processes |
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Term
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Definition
| produce myelin in the CNS |
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Term
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Definition
| have phagocytic activity and act as antigen presenting cells |
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Definition
| structural function; control ionic and chemical environment of neurons |
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Definition
| represented by tight junctions of astrocytes; allows free passage of glucose but excludes most substances |
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| characteristic of ganglia |
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Definition
| 1.ovoid stuctures with neuronal cell bodies and supportive cells; 2. relay stations to transmit nerve impulses |
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Term
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Definition
| consists of axon, myelin sheath, and Schwann cells; grouped in fascicles by connective tissue sheaths (epineurium, perineurium, endoneurium) |
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Term
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Definition
| caused by damage to neurons and their axons; 1. degeneration of distal stump is chromatolysis; 2. myelin sheath can be damaged too (segmental demyelination) causing muscle paralysis |
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Term
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Definition
| 1. injury to nerve results in proliferation of Schwann cells and bridge the gap between the proximal and distal stumps-also phagocytize myelin; 2. proximal stump generates multiple sprouts between Schwann cells; 3. when axon reaches end organ the Schwann cells produce myelin |
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Term
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Definition
| during development, axons become invested in Schwann cells; those that are to be myelinated increase in size and become invested in one Schwann cell while unmyelinated axons remain small |
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Term
| non-myelinated nerve fibers |
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Definition
| 1. several invested in cytoplasm of one Schwann cells; 2. majority of postganglionicc axons from autonomic ganglia; 3. impulses travel continously and less rapidly than saltatory conduction |
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Term
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Definition
| region of apposition of schwann cell plasma membrane along teh opening of the channel that the axon is embedded in |
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Term
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Definition
| 1. invagination of single axon into Schwann cell and cell wraps one full turn and external surfaces make contact with one another; 2. mesaxon rotates around the axon, enveloping axon in concentric layers of cytoplasm and plasma membrane; 3. cytoplasm is excluded and inner leaflets of plasma membrane fuse with each other; 3. spiraling continues until axon surround by multiple layers of membrane |
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Term
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Definition
| occurs by oligodendrocytes providing myelin sheath to several axons; no basal lamina associated with myelin sheath in CNS |
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Term
| differences between PNS and CNS myelination |
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Definition
| 1. oligodendrocyte-many myelin sheaths, schwann cell-single axon; 2. no cytoplasm of the oligodendricyte is trapped; 3. in CNS surface of node is contacted by astrocyte process, in PNS the node is covered by schwann cell processes |
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Term
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Definition
| segment of myelin formed by individual oligodendrocyte processes |
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Term
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Definition
| observed between axolemma surrounding the axon and the cytoplasmic loops adjacent to the node of Ranvier (claudins and zonula occludens); function for stability, permeability, fluidity |
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Term
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Definition
| expressed in Schwann cells and mutation results in demyelinating disorder of PNS (X-linked Charcot-Marie Tooth Disease) |
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Term
| resting membrane potential |
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Definition
| voltage difference across cell membrane from ionic differences of Na, K, and Ca |
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Term
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Definition
| 1. nerve pulse initiated and membrane potential changes; 2. causes sodium channels to open; 3. once depolarizes potassium channels open up to repolarize the cell |
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Term
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Definition
| action potential travels down fiber and jumps from node to node and greatly enhances conduction velocity of axons |
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Term
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Definition
| immune mediated demyelinating disease, increase in IgGs, CSF, and abnormal T cell function |
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Term
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Definition
| progressive degeneration of motor neurons, starts with weakness in limbs progressive to severe paralysis |
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Term
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Definition
| encapsulated nerve ending in deeper layers of the skin |
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Term
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Definition
| occurs in skin on the palms, fingers and toes, is enlogated, pear shaped and is vertical to axis of the skin (sensory nevre ending in the skin) |
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Term
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Definition
| Schwann cell and its basal lamina |
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