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Nervous System. Cellular & Tissue L evel. Objectives. Describe the general structure of a neuron. Explain how neurons are classified. Name the types of neuroglia and describe the structure and function of each. Locate cells of the nervous system in the body.
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Nervous System Cellular & Tissue Level
Objectives • Describe the general structure of a neuron. • Explain how neurons are classified. • Name the types of neuroglia and describe the structure and function of each. • Locate cells of the nervous system in the body.
The nervous system is composed predominantly of neural tissue, but also includes blood vessels and connective tissue.
Cells of the Nervous System Neurons Neuroglia Not nerve cells! Supporting cells Do not transmit impulses • The basic units of the nervous system • Nerve cells • Conduct impulses
Types of Neurons • Neurons may be classified in two ways: by structure or function. • Functional classification of neurons • Motorneurons • Sensoryneurons • Interneurons
Motor Neurons • Over half a million in the human body • Carry instructions from the CNS to other tissues, organs, or organ systems. • Peripheral targets = effectors
Sensory Neurons • Approximately 10 million in the human body • Form the afferent division of the PNS • Receive information from sensory receptors and then relay that information to neurons in the CNS • aka. Afferent neurons
Interneurons • aka. Associated/association neurons • Located entirely in the brain and spinal cord • Connect other neurons • Responsible for the distribution of sensory information and coordination of motor activity • Transferring, processing, interpreting
http://science.howstuffworks.com/environmental/life/human-biology/brain2.htmhttp://science.howstuffworks.com/environmental/life/human-biology/brain2.htm
Neuroglia CNS PNS Schwann cells Satellite cells • Astrocytes • Oligodendrocytes • Ependyma • Microglia