Chapter 20 - Structure of the Nervous System Divided into...

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Structure of the Nervous System • Divided into two parts – Central nervous system (CNS) – Peripheral nervous system (PNS)
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Structure of the Nervous System [INSERT FIGURE 20.1]
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Structure of the Nervous System Structures of the Central Nervous System – Composed of the brain and spinal cord – Brain has several main parts Cerebrum controls voluntary muscles, perception, and “thinking” Cerebellum controls many involuntary body movements Brain stem controls breathing, heart rate, blood pressure – Spinal cord • Extends from the brain stem to the lumbar region
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Structure of the Nervous System Structures of the Peripheral Nervous System – Composed of nerves that transfer commands from CNS to muscles and glands – Cranial nerves extend from the brain through holes in the cranial bones – Spinal nerves extend from the spinal cord through gaps between the vertebrae – Three types of nerves • Sensory nerves – carry signals toward the CNS • Motor nerves – carry signals away from the CNS • Mixed nerves – carry signals toward and away from the CNS
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Structure of the Nervous System Cells of the Nervous System – Two basic cell types • Neuroglia – Provide support, insulation, nutrients, phagocytize microbes • Neurons – Carry nerve impulses – Nucleus lies in a region called the cell body – A collection of many neurons’ cell bodies is called a ganglion – Dendrites and axons extend from the cell body
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Structure of the Nervous System Portals of Infection of the Central Nervous System – CNS is an axenic environment • It has no normal microbiota – Pathogens may access the CNS several ways • Breaks in the bones and meninges • Medical procedures • Traveling in peripheral neurons to the CNS • Infecting and killing cells of the meninges resulting in meningitis
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Bacterial Diseases of the Nervous System • Bacteria cause disease in two ways – Infect cells of the nervous system • Meningitis • Leprosy – Bacteria growing elsewhere release toxins that affect neurons • Botulism • Tetanus
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Bacterial Diseases of the Nervous System Bacterial Meningitis – Signs and symptoms • Sudden high fever and severe meningeal inflammation • Inflamed cranial meninges – severe headache, vomiting, pain • Inflamed spinal meninges – stiff neck, altered muscle
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This note was uploaded on 05/24/2011 for the course BIO 119 taught by Professor Stevendroho during the Spring '11 term at Moraine Valley Community College.

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Chapter 20 - Structure of the Nervous System Divided into...

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