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Uniquely designed to receive and transmit electrical and chemical signals throughout the body.
Nervous (or neural) tissue
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Nervous tissue is found in the
Brain, spinal cord, and peripheral nerves
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Nervous tissue is composed primarily of two general cell types:
- Neurons
- Neuroglial Cells (support the neurons)
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Longest cells in the body and may reach up to a yard in length.
Neurons
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Neurons are composed of three primary parts:
- Perikaryon (stroma) – cell body
- Dendrites – short cytoplasm extension
- Axon – long single extension of cytoplasm.
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Function of dendrite
receive impulses from the other cells
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Function of axon
conducts impulses away from the cell body.
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Found in greater numbers in neural tissue. They do not transmit impulses but rather serve to support.
Neuroglial cells
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Specialized types of neuroglial cells function to
- Isolate the conductive membranes
- provide a supportive framework that helps to bind the components to neuronal tissue together
- phagocytize debris
- help supply nutrients to neurons by connecting them to blood vessels
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Which systems maintain homeostasis.
endocrine and nervous system
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Nervous system has three basic functions:
- sensory functions (externally),
- integrating functions (within the spinal cord),
- motor functions (externally).
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Nervous system consist of two parts:
- Central Nervous System: Brain, Spinal Cord
- Peripheral Nervous System: Cranial Nerves, Spinal Nerves, Autonomic Nerves, Sympathetic Division, Parasympathetic Division
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The cell body (soma or perikaryon) is large and contains:
- the nucleus of the cell.
- majority of the cell organelles that synthesize the materials needed by the neuron (neurone), particularly energy (mitochondria) and neurotransmitters (synthesized by the ribosomes and rough endoplasmic reticulum).
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Some of the areas containing large amounts of Rough ER and ribosomes stain darkly and these areas are referred to as
Nissl bodies
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The Nissl bodies give the grey coloration to the areas of the spinal cord that contain the cell bodies of the neurons, the so-called
grey matter.
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