The body must react to the external environment and the internal environment and communicate information between regions of the body. This job is primarily the task of the nervous system. Proper response to the external environment is critical for thermal regulation, response to threats, taking advantage of opportunities such as food availability, and a host of other stimuli. Response to the internal environment is important for sensing muscle tension, digestive processes, maintenance of blood pressure, and other functions. Communication is important for coordination of activities such as walking, digestion, and maintenance of blood pressure. The nervous system also integrates information from the environment, relates past information to the present and interprets new experiences. The brain and the spinal cord make up the central nervous system. The nerves of the body make up the peripheral nervous system. The peripheral nervous system is divided into the somatic nervous system which consists of spinal nerves and peripheral nerves that innervate the outer regions of the body. It also consists of the autonomic nervous system. Label the parts of the nervous system and color them in.
Answer Key: a. Central nervous system, b. Brain, c. Spinal cord, d. Peripheral nervous system, e. Spinal nerves, f. Peripheral nerve
The nerve cell or neuron is the functional cell in the nervous system. Most electrical conduction in the body is due to the transmission of impulses by the neuron. The neuron consists of branched structures called dendrites. The main portion of the nerve cell is called the soma or nerve cell body, and the elongated part of the neuron is the axon. Two neurons are connected by gaps called synapses. The nerve cell body is the metabolic center of the cell consisting of a nucleus, an endoplasmic reticulum called the Nissl bodies, and a region where the axon attaches called the axon hillock. Color in the parts of the neuron and label the parts.
Answer Key. a. Dendrites, b. Nerve cell body (soma), c. Nissl bodies, d. Axon hillock, e. Axon, f. Synapses meclical 107
Neuroglia or glial cells have many specialized functions in the nervous system. The neurolemmocyte or Schwann cell is found in the peripheral nervous system. These cells make up the myelin sheath that wraps around axons.
The other neuroglia are located in the central nervous system. Astrocytes are glial cells that, along with the brain capillaries, are found in the blood-brain barrier. They also have a role in transferring nutrients from the capillaries to the deeper regions of the brain. Another glial cell that functions as a barrier is the ependymal cell. These cells are located between the CNS and cavities filled with cerebrospinal fluid. Microglia are also found in the CNS and their function is one of protection. Microglia respond to invasions of the nervous system and they destroy microbes.
Oligodendrocytes are neuroglia that produce myelination in the CNS. Myelinated nerve fibers comprise white matter. Myelinated fibers conduct impulses faster than unmyelinated fibers. White matter is mostly associated with transmission of neural impulses from one area to another. Color each glial cell a different color and write the name of each cell in the space provided.
Answer Key: a. Astrocyte, b. Ependymal cell, c. Microglial cell, d. Oligodendrocyte, e. Neurolemmocytes (Schwann cells), f. Myelin sheath, g. Axon
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