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7 Cards in this Set
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1. Describe the general functions of the nervous system.
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The nervous system has three general functions: 1. a sensory function, 2. an interpretative function and a 3. motor function. Sensory nerves gather information from inside the body and the outside environment. The nerves then carry the information to central nervous system (CNS).
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2. Identify the two types of cells that comprise nervous tissue.
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The nervous system is composed of: 1. neural tissue, including a. neurons and b. neuroglia cells 2. blood vessels 3. connective tissue |
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Identify the two major groups of nervous system organs.
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Organs of the nervous system are divided into: 1. central nervous system: brain & spinal cord 2. peripheral nervous system: nerves that extend from the brain (cranial nerves) and spinal cord (spinal nerves). |
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List the functions of sensory receptors
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Three Major Functions 1. Sensory Input Function a. PNS b. Sensory receptors (located at the ends of peripheral neurons) detect changes occurring in their surroundings (i.e. are stimulated). c. Once stimulated, sensory receptors transmit a sensory impulse to the CNS. d. A sensory impulse is carried on a sensory neuron. 2. Integrative Function a. CNS (brain and/or spinal cord)b. involves interpretation of an incoming sensory impulse (i.e. decision is made concerning what's going to happen next, based on sensory impulse).c. Integration occurs in interneurons.d. A motor impulse begins... 3. Motor Function a. PNSb. involves the response of a body partc. Motor impulses are carried from CNS to responsive body parts called effectors.d. A motor impulse is carried on a motor neuron.e. Effectors = 2 types: o muscles (that contract) o glands 1. that secrete a hormone, endocrine 2. that secrete a substance; exocrine |
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Describe how the nervous system responds to stimuli.
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When a stimulus is received by a sensory neuron, the impulse (or message) is carried through fibrous extensions called dendrites to the cell body. The cell body is made up of cytoplasm, cytoplasmic structures, and a nucleus, which controls neuron function. The impulse travels through the cell body and is carried through the axon to the end brush, a collection of fibers that extend off the axon. Here, the impulse triggers a release of chemicals that allow the impulse to travel through the synapse—the space between the axon of one neuron and the dendrites of the next. An impulse travels along the neuron pathways as electrical charges move across each neural cell membrane. Ions moving across the membrane cause the impulse to move along the nerve cells.
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Describe the three major parts of a neuron
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Cell Body (soma or perikaryon) = central portion of neuron contains usual organelles, except centrioles o identify: nucleus, prominent nucleolus, and many Nissl bodies (chromatophilic substance) = RER.o A network of fine threads called neurofibrils extends into the axons and supports them.b. Neuron Processes/ Nerve Fibers = extensions arising from cell body. Two types: Dendrites: 1. many per neuron 2. short and branched 3. receptive portion of a neuron4. carry impulses toward cell body Axons:1. one per neuron 2. long, thin process 3. carry impulses away from cell body4. Note terminations of axon branch = axonal terminals or synaptic knobs.5. Axons in CNS (i.e. in brain & spinal cord) a. Myelin is produced by an oligodendrocyte rather than Schwann Cells.b. A bundle of myelinated nerve fibers = "White Matter".c. This is in contrast to CNS "Gray Matter" = A bundle of cell bodies (or unmyelinated nerve fibers). |
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Define neurofibrils and chromatophilic substance
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1. chromatophilic substances (kro´´mua-to-fil´ik) Clumps of rough endoplasmic reticulum in the cell bodies of neurons; also called Nissl bodies. 2. neurofibrils: a fibril in the cytoplasm of a nerve cell, visible by light microscopy |
