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23 Cards in this Set
- Front
- Back
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Nervous System Functions
(2 Functions) |
*Body's primary communication and control system
*divided according to structural and functional categories |
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Stuctural Organization of the Nervous system:
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Central Nervous System (CNS)
*brain and spinal cord Peripheral Nervous System *cranial nerves, spinal nerves, ganglia (group of cell bodies) |
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Functional Organization
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*sensory (Afferent) division
*motor (efferent) division |
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Sensory (Afferent) division
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-transmit information FROM RECEPTORS TO CNS
-divided into somatic and visceral sensory gathering info |
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Motor (Efferent) division
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-transmit information FROM CNS TO MUSCLE OR GLAND
-divided into somatic and autonomic motor |
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Neurons
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excitable cells that transmit nerve impulses
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Glial cells
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non-excitable cells that support and protect the neurons
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Neuron Characteristics
(3) |
-high metabolic rate (need constant glucose and oxygen)
-longevity (live and function for over 100 years) -nonmiotic (during fetal development, lose ability to divide) |
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Primary tumor
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*tumors may form in the meninges (meningiomas) or glial cells (gliomas)
*Neuronsare incapable of becoming tumors because they cannot divide **originated in that organ |
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Secondary tumor
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tumor forms in another site but spreads to the brain (lung, skin, or breast cancers)
**originate somewhere else |
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Look at:
NEURON ANATOMY *be able to label |
pg. 74
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Dendrites
(3 functions) |
*carry impulses toward the cell body
*soma can have one or many dendrites *receive input and transfer to cell body for processing |
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cell body
(6 characteristics) |
*also called SOMA
*neuron control center) *contains nucleus and organelles *comprise "gray matter" *form clusters in PNS called ganglia *form clusters in the CNS called nuclei |
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axons
(5 characteristics) |
*most neurons have one axon (anaxonic neurons have no axon)
*the axon is also called the NERVE FIBER *carry impulses away from cell body to another *transmits its output information to other cells *ends branch into synaptic knobs |
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neuron classification: structural
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*unipolar
-sensory neurons *bipolar -special senses -uncommon in humans *multipolar -motor neurons -most common type -interneurons |
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neuron classification: functional
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*sensory (afferent)- from sensory receptors TO CNS
*interneurons - lie between motor and sensory neurons; entirely confined to CNS. may or may not be present. *motor (efferent)- FROM CNS to muscles or glands |
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Glial Cells of CNS
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*astrocyte- control ionic environment, help form BBB
*ependymal- help produce and circulate cerebral spinal fluid (CSF) *Microglial - macrophages of CNS *Oligodendrocyte- forms myelin sheaths in CNS |
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Nerves
**diagram page 78 |
-cable-like bundle of axons
-3 connective tissue wrappings endoneurium surrounds individual axon perineurim- surrounds individual fascicles epineurium- surrounds whole nerve |
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synapses
*diagram page 78 |
*site at which neurons communicate with other neurons, glands, or muscles
*have 3 parts: presynaotic neurons (synaptic vessicles contain neurotransmitters), synaptic cleft, postsynaptic neuron |
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Amyotrophic Lateral Sclerosis
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*Also called ALS or Lou Gehrig Disease
*fatal degeneration of the somatic motor system *Atrophied muscles cause breathing speaking and swallowing differculties *no effective treatment or cure exists |
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Multiple sclerosis
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*autoimmune disease
*patches of myelin in brain and spinal cord destroyed *affects 1 out of every 1000 people *symptoms: blindness, weakness, clumsiness |
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Anencephaly
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*disorder at the cranial end of the neural tube
*substantial or complete absence of brain (only brain stem forms) *infants rarely live longer than a few hours following birth *usually detected with prenatal ultrasound |
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spina bifida
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*disorder at the caudal end of the neural tube
*vertebral arch is not fully formed *may be milld (spina bifida occulta) or severe (spina bifida cystica) *increased intake of vitamin b12 and folic acid while pregnant decrease incidence of spina bifida |
