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Cards In This Set
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The two main divisions of the nervous system
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1. central nervous system and 2. peripheral nervous system
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Divisions of the CNS
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1. brain and 2. spinal cord
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Divisions of the peripheral NS
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1. somatic nervous system (interacts with the external environment) and 2. autonomic nervous system (regulates the body's internal environment)
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Function of the efferent and afferent nerves of the somatic NS
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Efferent: to carry signals from the CNS to the skeletal muscles, afferent: carry signals from the skin, skeletal muscles, joints, eyes, ears, etc. to the CNS
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Function of the efferent and afferent nerves of the autonomic NS
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Efferent: to carry motor signals from the CNS to internal organs, afferent: to carry sensory signals from internal organs to the CNS
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2 types of efferent nerves in the autonomic NS
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1. sympathetic nerves (motor nerves, project from the CNS in the lumbar and thoracic regions of the spinal cord) and 2. parasympathetic nerves (motor nerves, project from the brain and sacral region of the spinal cord) - both are two-stage neural paths, meaning that they project from the CNS and go only part way to the target organs before they synapse of other neurons that carry the signals the rest of the way - sympathetic: synapse far away from target organs, parasympathetic: synapse near target organs
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Functions of the sympathetic nervous system
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The sympathetic nerves stimulate, organize, and mobilize energy resources in threatening situations - sympathetic changes are indicative of psychological arousal
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Functions of the parasympathetic nervous system
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Parasympathetic nerves act to conserve energy - parasympathetic changes are indicative of psychological relaxation
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Where are the cranial nerves located?
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In the peripheral nervous system - they project from the brain rather than from the spinal cord like most peripheral nerves
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How is the CNS protected?
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The brain and spinal cord are encased in bone and covered by 3 protective membranes: the 3 meninges: 1. dura mater, 2. arachnoid membrane, and 3. pia mater - other structures that provide support are: cerebrospinal fluid, central canal, cerebral ventricles, choroid plexuses, and subarachnoid space
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Dura mater
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The outermost meninx - tough
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Arachnoid membrane
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Immediately inside the dura mater - fine, spiderweb-like membrane
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Subarachnoid space
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Exists under the arachnoid membrane and contains many large blood vessels and cerebrospinal fluid
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Pia mater
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Innermost meninx - delicate - adheres to the surface of the CNS
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Cerebrospinal fluid
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Fills the subarachnoid space, the central canal of the spinal cord, and the cerebral ventricles of the brain - function: to support and cushion the brain
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