BIOL 240: Exam 3
36 Cards in this Set
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Functions of the nervous system
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Sensory input: receptor monitor stimuli inside & outside body
Integration: process, interprets, assimilates experiences
Motor output: responds; muscle contraction, glandular secretion
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CNS
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brain and spinal cord
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PNS
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nerves and ganglia
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ganglion
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collection of neuron cell bodies
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sensory (afferent)
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picked up by sensor receptors
-carries by nerve fibers of PNS to CNS
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Motor (Efferent)
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signals carried away from the CNS
-innervated muscles and glands
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somatic sensory
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receives sensory info from skin, proprioception, vision, hearing, etc.
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visceral sensory
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receives sensory info from viscera
-taste, smell, hunger
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somatic motor
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contraction of skeletal muscle
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visceral motor
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automatic nervous system; contraction of smooth and cardiac muscles, glandular secretions
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Glial Cells
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*Found in both CNS & PNS
*Smaller & capable of mitosis
*Protect, nourish neurons
*Provide organized, supporting framework *More abundant than neurons
(~half volume of NS)
*Not capable of impulse trans.
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types of Glial cells found in CNS
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Astrocytes**
ependymal cells
mircoglia
oligodenrocytes
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Types of Glial Cells in PNS
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Satellite Cells
Neurolemmocytes
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Astrocytes
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star shaped
most abundant of glial cells
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functions of astrocytes
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Connect neurons to blood vessels
Control flow of substances
Control chemical composition
Provide framework & support
Replace neurons
Resynthesize neurotransmitters
Regulate neuron connect. (fetal brain)
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The Blood-Brain Barrier (BBB)
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*Astrocytes + capillaries form the BBB, which controls substances entering the brain from the bloodstream
*Brain capillaries less “leaky” than other capillaries
*BBB absent at the choroid plexus, hypothalamus, pineal gland
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Ependymal Cells
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*Cuboidal epithelial cells
*Found in ventricles and central canal of the spinal cord
*Have basal projections to contact other glial cells.
*Have cilia (help circulate CSF)
*Along with blood vessels., they form choroid plexus
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Function of Ependymal cells
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produce CSF
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Microglial Cells
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*Small cells with projections
*Not abundant (%5 of abundance) *Do not originate in nervous tissue *Modified monocytes (WBC) *Phagocytic activity: remove debris
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Oligodentrocyte Cells
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*Large cells with globular bodies & slender projections
*Form myelin sheaths (protective covering) in axons; insulation, protection, nourishment *One cell can wrap around multiple axons
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Satellite Cells
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*Flattened cells around neuronal body in ganglia *Regulate nutrient & waste exchange
**similar in function to astrocytes
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Nrurolemmocytes (Schwann Cells)
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*Surround axons
* insulation, protection, nourishment
*Form myelin sheaths
**similar in function to oligodendrocytes
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Neurons
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*Capable of transmitting electrical impulses
*High metabolic rate: abundant mitochondria
*Need glucose and oxygen
*Can live and function for a lifetime *Cannot divide mitotically, except:
olfactory neurons, hippocampus
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nuclei
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clusters of neuron bodies in CNS
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Ganglia
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clusters of neuron bodies in PNS
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bundles of axons in CNS
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tracts
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bundles of axons in PNS
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fibers
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sensory functions of neurons
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*Sensory (Afferent) neurons
-originate in sensory receptors -respond to stimuli
- travel to CNS
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function of motor (efferent) neurons
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-originate in CNS
-travel to an effector (muscle or gland)
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function of interneurons
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-located between motor and sensory neurons -found in CNS
-make up 99.98% of neurons in body
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Unipolar Neuron
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typical sensory neuron
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bipolar neuron
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rare-found in retina, nose, inner ear
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multipolar neuron
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most common type of motor & interneurons
cell body mostly in CNS
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SAME DAVE
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sensory-afferent
motor-efferent
dorsal-afferent
ventral-efferent
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afferent
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sensory
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efferent
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motor
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BIOL 240: Exam 3