Final Study guide - CNS nd close in response to changes in...

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nd close in response to changes in membrane voltage. nsmitter binds to the receptor, allowing (in this case) simultaneous movement of Na + and K + . CNS – Consist of brain and spinal cord. Is the integrating and command; interprets sensory input and indicates motor responses based on reflexes. PNS - Part of the nervous system but outside of the CNS. Consist mainly of the nerves (Bundle of axons) that extend from the brain and spinal cord. Spinal nerves impulses to and from spinal cord; Cranial Nerves impulses to and from the brain, These PNS serves as the communication lines that links all parts of the body to the CNS. Functions of CNS and PNS CNS Sensory input Information gathered by sensory receptors about internal and external changes Integration Interpretation of sensory input Motor output Activation of effector organs (muscles and glands) produces a response PNS Two functional divisions o Sensory (afferent) division Somatic afferent fibers—convey impulses from skin, skeletal muscles, and joints Visceral afferent fibers—convey impulses from visceral organs o Motor (efferent) division Transmits impulses from the CNS to effector organs Divisions of Nervous System Central nervous system (CNS) Brain and spinal cord Integration and command center Peripheral nervous system (PNS) Paired spinal and cranial nerves carry messages to and from the CNS Motor Division of PNS 1. Somatic (voluntary) nervous system Conscious control of skeletal muscles 2. Autonomic (involuntary) nervous system (ANS) Visceral motor nerve fibers Regulates smooth muscle, cardiac muscle, and glands Two functional subdivisions 1. Sympathetic - Stimulates 2. Parasympathetic – Inhibits
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Neuron Characteristics Special characteristics: Long-lived ( 100 years or more) Amitotic—with few exceptions High metabolic rate—depends on continuous supply of oxygen and glucose Plasma membrane functions in: Electrical signaling Cell-to-cell interactions during development Two principal cell types 1. Neurons —excitable cells that transmit electrical signals Neuroglia (glial cells)— supporting cells: Astrocytes (CNS) Most abundant, versatile, and highly branched glial cells Cling to neurons, synaptic endings, and capillaries Support and brace neurons Help determine capillary permeability Guide migration of young neurons Control the chemical environment Participate in information processing in the brain Microglia (CNS) Small, ovoid cells with thorny processes Migrate toward injured neurons Phagocytize microorganisms and neuronal debris Ependymal cells (CNS) Range in shape from squamous to columnar May be ciliated Line the central cavities of the brain and spinal column Separate the CNS interstitial fluid from the cerebrospinal fluid in the cavities Oligodendrocytes (CNS) Branched cells Processes wrap CNS nerve fibers, forming insulating myelin sheaths
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Final Study guide - CNS nd close in response to changes in...

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