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What is the nervous system
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About 3% of total body weight, one of the smallest but most complex systems.
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What are some structures of the nervous system?
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Brain, cranial nerves and their branches, ganglia, enteric plexuses, sensory receptors.
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The brain is...
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Enclosed by the skull, contains 100 billion neurons, and 12 pairs (rgt and lft) of cranial nerves.
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What is a nerve?
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A bundle of hundreds to thousands of axons w/ associated tissue and blood vessels that lies outside of the brain and spinal cord.
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What is the function of the spinal cord?
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Connects the brain through the foramen magnum of the skull and is encircled by the bones of the vertebral colum, contains 100 million neurons.
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Spinal nerves
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31 prs, that emerge from the spinal cord, each serving a specific region on the right and left side of the body.
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Ganglia
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Small masses of nervous tissue, consisting mostly of neuron cell bodies, located outside of brain and spinal cord
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Enteric plexuses
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Extensive neurons that help regulate the digestive system
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Sensory receptor
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Used to refer to dendrites of sensory neurons as well as separate, specialized cells that monitor changes in internal or external enviroment
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Function of the nervous system
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Carries out a complex array of tasks, grouped into 3 basic functions: sensory, integrative, motor
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Sensory function
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Detect internal stimuli. Info carried to brain/spinal cord through spinal & cranial nerves
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Integrative function
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Nervous system integrates information by analyzing & storing. Connects Sensory and motor functions.Important function, perception
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Perception
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The conscious awareness of sensory stimuli
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Motor function
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Activates effectors (muscles and glands) through cranial and spinal nerves. Stimulation of the effectors causes contraction and secretion.
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What are the two subdivisions of the nervous system?
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Central nervous system (CNS), Peripheral nervous sytem (PNS).
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