Nerve Signals Maintaining Homeostasis

Nerve Signals Maintaining Homeostasis - HOW NERVE SIGNALS...

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HOW NERVE SIGNALS MAINTAIN HOMEOSTASIS 8.1: The Importance of the Nervous System: The nervous system has two divisions: the central nervous system (CNS) and the peripheral nervous system (PNS) The CNS consists of the nerves of the brain and spinal cord; it acts as a coordinating centre for incoming and outgoing information The PNS consists of nerves that carry information between the organs of the body and the CNS The PNS can be further divided into two subsections: somatic and autonomic nerves The somatic nervous system controls the skeletal muscle, bones and skin Sensory somatic nerves relay information about the environment to the CNS Motor somatic nerves initiate an appropriate response The autonomic nervous system contains special motor nerves that control the internal organs of the body The two divisions of the autonomic system are: sympathetic and parasympathetic Anatomy of a Nerve Cell Two different types of cells: glial and neurons ; both found in the nervous system Glial cells often called neuroglial are nonconducting cells are important for the structural support and metabolism of the nerve cells Neurons are the functional units of the nervous system
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A group of neurons make up a nerve Neurons are nerve cells that conduct nerve impulses Neurons are categorized into three groups: sensory, interneuron and motor neurons Sensory neurons (also known as afferent neurons) sense and relay information (or stimuli) from the environment to the central nervous system A cluster of sensory neurons are called ganglia (singular is called ganglion) which is located outside the spinal cord Then, the message is sent along the interneurons (also called association neurons), which links all the neurons in the body together The interneurons are found predominantly throughout the brain and spinal cord Interneurons integrate and interpret the sensory information and connect neurons to outgoing motor neurons Motor neurons (also called efferent neurons) relay this information to the effectors The effectors like muscles, organs and glands carry out the response based on the information relayed from the motor neuron All neurons contain dendrites, cell bodies and axons Dendrites receive information, either from sensory receptors (from sensor neurons) or from other nerve cells like motor neurons Like all cells, neurons also contain a cell with a nucleus Dendrites conduct nerve impulses towards the cell body Axons are extensions of the cytoplasm that projects nerve impulses from the cell body In humans, axons are extremely thin
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Axons carry nerve impulses towards other neurons or to effectors like muscles Many axons are covered with a white coated fatty protein called the myelin sheath The myelin sheath acts as insulation for the neurons and axons with myelin are said to be myelinated Myelin sheath are formed by Schwann cells (special type of glial cells that
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Nerve Signals Maintaining Homeostasis - HOW NERVE SIGNALS...

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