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36 Cards in this Set
- Front
- Back
List the five main functions of the nervous system
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1) Sensory input
2) Integration 3) Homeostasis 4) Mental Activity 5) Control of muscles and glands |
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Sensory receptors
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the endings of nerve cells or separate, specialized cells that detect temperature, pain, touch, pressure, light, sound, odors, and other stimuli; located in various locations throughout the body
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Nerve tract
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bundles of parallel axons with their associated sheaths in the CNS
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Ganglion
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any group of nerve cell bodies in the PNS
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Plexus
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intertwining of nerves or blood vessels
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Afferent division
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nerve fibers that send impulses from the periphery to the CNS
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Efferent division
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nerve fibers that send impulses from the CNS to the periphery
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Somatic nervous system
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composed of nerve fibers that send impulses from the CNS to skeletal muscle
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Autonomic nervous system
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composed of nerve fibers that send impulses from the CNS to smooth muscle, cardiac muscle, and glands
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Sympathetic division
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subdivision of the autonomic nervous system characterized by having the cell bodies of its preganglionic neurons located in the thoracic and upper lumbar regions of the spinal cord (thoracolumbar division); usually involved in preparing the body for physical activity
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Parasympathetic division
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subdivision of the autonomic nervous system; characterized by having the cell bodies of its preganglionic neurons located in the brainstem and the sacral region of the spinal cord (craniosacral division); usually involved in activating vegitative functions such as digestion, defecation, and urination
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Enteric nervous system
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consists of plexuses within the wall of the of the digestive tract; considered part of the ANS
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Astrocytes
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neuroglia that are star-shaped due to cellular processes that extend out toward other cells; play a role in regulating the extracellular composition of brian fluid; release chemicals that promote the formation of tight junctions between the endothelial cells of capillaries, helping to form the blood-brain barrier
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Blood-brain barrier
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a barrier that forms between the blood vessels and nervous tissue; determines what substances can pass from the blood into the nevous tissue of the brain and spinal cord; protects brain from toxic substances in the blood, allows the exchange of nutrients and waste products, and prevents fluctuations of in the composition of the blood from affecting the functions of the brain
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Ependymal cells
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cells that line the ventricles of the brain and central canal of the spinal cord
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Choroid plexuses
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specialized plexus located within the ventricles of the brain the secretes CSF
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Microglia
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small neuroglial cells that become phagocytic and mobile in response to inflammation; considered to be macrophages within the CNS
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Oligodendrocytes
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neuroglial cells that have cytoplasmic extensions that form myelin sheaths around axons in the CNS; one cell can myelinate multiple neurons
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Schwann cells (neurolemmocytes)
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neuroglial cells that wrap around axons in the PNS; each only wraps around one axon
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Satellite cells
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neuroglial cells that surround neuron cell bodies in ganglia, provide support, and can provide nutrients to the neuron cell bodies
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Myelinated axons
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neuron axons that are surrounded by extensions of oligodendrocytes or Schwann cells wrapped many times; gives the axon a white appearance due to high lipid concentrations
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Nodes of Ranvier
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2-3um interruptions in the myelin sheath that permit quicker electrical conductance up the axon
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Internodes
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the myelinated areas located between the nodes of Ranvier
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White matter
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bundles of parallel axons with their associated myelin sheaths; whitish in color
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Gray matter
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collections of neuron cell bodies and unmyelinated axons; grayish in color
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Nerve tracts
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bundles of axons in the CNS that serve to "connect" different areas of the nervous system by propogating action potentials from one area to another
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Cortex
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area in the periphery of the brain that is composed of gray matter
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Nuclei
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areas within the brain that are composed of collections of gray matter
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Action Potential
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change in membrane potential in an excitable tissue that acts as an electric signal and is propagated in an all-or-none fashion
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Na+/K+ pump
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biochemical mechanism that uses energy derived from ATP to achieve the active transport of potassiumions opposite to that of sodium ions
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Nongated ion channels
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also called leak channels; channels that are always open and are responsible for the permeability of the plasma membrane to ions when the plasma membrane is unstimulated, or at rest; plasma membrane is more permeable to K+ and Cl- and much less permeable to Na+
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Gated ion channels
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channels that open and close in response to stimuli;
can change the permeability characteristics of the plasma membrane; there are three types: ligand-gated, voltage-gated, and other-gated ion channels |
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Ligand
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a molecule that binds to a receptor
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Receptor
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a protein or glycoprotein that has a receptor site to which a ligand can bind; most are located within the plasma membrane
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Ligand-gated ion channel
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ion channels that open or close in response to a ligand binding to a receptor; exist for Na+, K+, Ca2+, and Cl-
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Voltage-gated channel
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ion channels that open and close in response to small changes across the plasma membrane;
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