| Term 
 | Definition 
 
        | 1. brain and spinal chord 2. interprets incoming sensory information and issues instructions
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        | Term 
 
        | peripheral nervous system |  | Definition 
 
        | 1. cranial, spinal nerves, ganglia, sensory receptors 2. carries impulses to and from CNS
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        | Term 
 | Definition 
 
        | basic functional units of nervous tissue |  | 
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 | Definition 
 
        | supporting cells for neurons |  | 
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 | Definition 
 
        | clusters of cell bodies of neurons, typically found in the CNS |  | 
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 | Definition 
 
        | collections of neuron cell bodies outside the CNS |  | 
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 | Definition 
 
        | neuron fibers running through the PNS (peripheral nerves) |  | 
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 | Definition 
 
        | neuron fibers running through the CNS (tracts of white matter) |  | 
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        | Term 
 | Definition 
 
        | 1. defensive cells in the CNS 2. act as macrophages
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        | Term 
 | Definition 
 
        | 1. form myelin sheaths around CNS nerve fibers via processes |  | 
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        | Term 
 | Definition 
 
        | 1. control the chemical environment around neurons 2. facilitate capillary-nerve exchanges
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 | Definition 
 
        | circulate cerebrospinal fluid |  | 
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 | Definition 
 
        | myelinate (insulate) the extensions of the neurons |  | 
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        | Term 
 | Definition 
 
        | surround cell body of the neuron |  | 
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        | Term 
 | Definition 
 
        | contains nucleus surrounded by cytoplasm |  | 
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 | Definition 
 
        | receptor regions for neurotransmitters released by other neurons |  | 
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        | Term 
 | Definition 
 
        | generate and conduct nerve impulses |  | 
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        | Term 
 | Definition 
 
        | form synaptic junctions with neurons or effector cells |  | 
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        | Term 
 | Definition 
 
        | large cell body structure before axon terminal |  | 
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        | Term 
 | Definition 
 
        | 1. Whitish fatty proteins covering some axons called myelinated axons 2. Concentric rings of the plasma membrane wrapped around an axon.
 3. Insulates fibers and increases the speed of transmission of nerve impulse
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        | Term 
 | Definition 
 
        | 1. intermediate filaments in the neuron 2. Function: provide tensile strength
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        | Term 
 | Definition 
 
        | 1. specialized endoplasmic reticulum 2. Function: protein synthesis
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        | Term 
 | Definition 
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 | Definition 
 
        | part of the Schwann cell external to the myelin sheath, housing the nucleus and cytoplasm |  | 
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        | Term 
 | Definition 
 
        | 1. carry impulses from internal organs, skin, skeletal muscles, joints, and sensory organs 2. often stimulated by specific changes in immediate environment
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        | Term 
 | Definition 
 
        | 1. carry impulses from the CNS to the viscera, body muscles, and/or glands 2. multipolar
 3. cell bodies located in CNS
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        | Term 
 
        | association neurons/interneurons |  | Definition 
 
        | 1. connect sensory and motor neurons, and situated between 2. cell bodies located in CNS
 3. multipolar
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        | Term 
 | Definition 
 
        | 1. A single process extending from the cell body – divided into peripheral and central processes 2. conduct impulses toward the CNS
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        | Term 
 | Definition 
 
        | 1. Two processes attached to the cell body – one dendrite, one axon 2. found only in the eye, ear, and olfactory mucosa
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        | Term 
 | Definition 
 
        | 1. Many processes issued from the cell body – many dendrites, one axon 2. most abundant type of neurons in the body
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        | Term 
 | Definition 
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 | Definition 
 
        | surrounds each neuron fiber |  | 
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 | Definition 
 
        | surrounds groups of neuron fibers to form fascicles |  | 
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        | Term 
 | Definition 
 
        | covers groups of fascicles, forming a nerve |  | 
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        | Term 
 
        | blood and lymphatic vessels |  | Definition 
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        | Term 
 | Definition 
 
        | 1. excitability--respond to stimuli by producing electrical symbol 2. conductivity--transmit signals to neurons, muscles, glands, and other body tissues
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        | Term 
 | Definition 
 
        | makes the neuron more permeable to Na+ ions |  | 
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        | Term 
 
        | resting membrane potential |  | Definition 
 
        | 1. excess of positive ions at external cell surface 2. Na+ is the extracellular ion
 3. K+ is the intracellular ion
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        | Term 
 | Definition 
 
        | changes membrane permeability to allow Na+ ions to flow into the cell |  | 
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 | Definition 
 
        | wave of depolarization spreads along membrane |  | 
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        | Term 
 | Definition 
 
        | 1. negative charge of inner membrane and positive charge of outer membrane is re-established 2. K+ diffuses out of the cell
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        | Term 
 
        | absolute refractory period |  | Definition 
 
        | Occurs when the sodium gates are still open (depolarization phase) and the neuron is unable to initiate a new action potential |  | 
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        | Term 
 
        | relative refractory period |  | Definition 
 
        | When the neuron is undergoing repolarization and therefore the sodium gates are closed an exceptionally strong stimulus can cause initiation of another action potential |  | 
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        | Term 
 | Definition 
 
        | name and number: olfactory (I) location: olfactory epithelium ti synapse in olfactory bulbs
 modality: sensory
 function: afferent impulses associated with sense of smell
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        | Term 
 | Definition 
 
        | name and number: optic (II) location: retina of eye to visual cortex of cerebrum
 modality: sensory
 function: afferent im[ulses associated with vision
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        | Term 
 | Definition 
 
        | name and number: oculomotor (III) location: dorsal midbrain to orbit
 modality: motor
 function: provides somatic motor fibers for direction of eyeball, reflex responses to varying light and eye focus
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        | Term 
 | Definition 
 
        | name and location: trochlear (IV) location: midbrain
 modality: motor
 function: provides somatic motor fibers to oblique muscles which move eyeball
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        | Term 
 | Definition 
 
        | name and number: trigeminal (V) location: pons
 modality: mixed (sensory and motor)
 function: conducts sensory impulses from face,  motor fibers innervate muscles for mastication
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        | Term 
 | Definition 
 
        | name and number: abducens (VI) location: inferior pons
 modality: motor
 function: carries somatic motor fibers to lateral rectus muscles that move eyeball
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        | Term 
 | Definition 
 
        | name and number: facial (VII) location: pons to face
 modality: mixed (Motor and sensory)
 function: supplies somatic motor fibers for facial expression, carries sensory fibers for taste
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        | Term 
 | Definition 
 
        | name and number: vestibulocochlear (VIII) location: inner-ear to pons
 modality: sensory
 function: transmits impulses for sense of equilibrium and hearing
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        | Term 
 | Definition 
 
        | name and number: glossopharyngeal (IX) location: medulla to throat
 modality: mixed (sensory and motor)
 function: motor fibers serve salivary glands, sensory fibers carry impulses from taste buds
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        | Term 
 | Definition 
 
        | name and number: vagus (X) location: medulla to thorax and abdomen
 modality: mixed (sensory and motor)
 function: paraympathetic motor fibers that supply heart and smooth muscles of abdominal visceral organs
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        | Term 
 | Definition 
 
        | name and number: accessory (XI) location: superior spinal chord to muscles of neck and back
 modality: mixed (primarily motor)
 function: provides somatic motor fibers to sternocleidomastoid
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        | Term 
 | Definition 
 
        | name and number: hypoglossal (XII) location: medulla to tongue
 modality: mixed (primarily motor)
 function: carries somatic motor fibers to muscles of tongue
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        | Term 
 | Definition 
 
        | hormone: growth hormone Target: muscle tissue and long bones of the body
 Action: growth of muscle and long bones of the body
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        | Term 
 | Definition 
 
        | hormone: oxytocin Target: uterus and mammary glands
 Action: stimulates powerful uterine contractions during birth
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        | Term 
 | Definition 
 
        | hormone: thyroid hormone Target: body cells
 Action: controls rate of body metabolism and cellular oxidation
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        | Term 
 
        | hypersecretion of thyroid |  | Definition 
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        | Term 
 | Definition 
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        | Term 
 | Definition 
 
        | hormone: parathyroid hormone (PTH) Target: bone matrix and kidneys
 Action: causes release of calcium from bone matrix, prods kidneys to produce more calcium, stimulates kidneys to convert Vitamin D to its active form
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        | Term 
 | Definition 
 
        | hormone: glucocorticoid (mainly cortisol) Target: body cells
 Action: increases blood glucose levels
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        | Term 
 
        | glucocorticoid hypersecretion |  | Definition 
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        | Term 
 | Definition 
 
        | hormone: insulin Target: blood/many cell types
 Action: decreases blood sugar levels
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 | Definition 
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