Nursing Preparation Study Guide

Nursing Preparation Study Guide • Sprain: Similar to a strain, but occurs when a ligament has been overstretched. 6.5 The Nervous System – Tour of the System The nervous system is an incredibly complex system, and along with the endocrine system, it holds the responsibility for maintaining homeostasis in the body. By doing so, it also controls other body systems and their functions. The nervous system consists of all the neural tissue in the body. There are two nervous system divisions: the central nervous system and the peripheral nervous system. The central nervous system (CNS) consists of the brain and the spinal cord. The CNS integrates, processes, and coordinates sensory data and motor commands. The CNS houses the structures that provide the higher functions, such as memory, emotion, learning, and intelligence. The peripheral nervous system (PNS) includes all the neural tissue outside the CNS. The PNS sends sensory information to the CNS and carries motor commands to the peripheral tissues, organs, andsystems that carry out the commands. The sensory, or afferent (which means “towards”), component of the PNS takes information from nerve cells throughout the body to the CNS. The motor, or efferent (which means “away from”), component of the PNS delivers information from the CNS to nerve cells. There are two components to this, the somatic nervous system and the autonomic nervous system (ANS): The somatic nervous system is voluntary and it controls information to muscles that are under voluntary control. This system is in use when we pick up a pen to start writing, for example. The autonomic nervous system is more complicated, as it is an involuntary system. This controls information to muscles that are not under voluntary control, such as the cardiac muscle and endocrine glands. This system controls our heart rate and releases epinephrine in the body, to name a few functions. The key cells involved in the nervous system are nerve cells, or neurons. Information in the nervous system is created and communicated in the form of electrical signals that are created by chemical changes in neurons. These signals are nerve impulses. 6.5.1 Functions There are three main functions: 1. The nervous system senses changes in the internal or external environment (changes are stimuli). 2. The nervous system analyses the stimuli, stores some information about it, and uses the remaining information to make decisions. 3. The nervous system often responds to stimuli by starting gland secretions or muscle movements.

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