The Nervous System Nervous system the body s electrochemical communication circuitry Characteristics of the Nervous System Complexity enormously complex Integration efficient at pulling information together in the body and the environment Plasticity the brain s special capacity for change Adaptability the brain and nervous system serve as our agent in adapting to the world They have a biological function but are constantly adapting to changes By changing the way you think you can literally change the brain s processes wiring and rewiring and even shape Electrochemical Transmission the brain and nervous system function as an information processing system that is powered by electrical impulses and The nervous system possesses specialized pathways that are adapted for different functions They are made up of afferent nerves efferent nerves and neural Afferent nerves sensory nerves carry information to the brain and spinal cord Communicate information about the external environment and internal body Efferent nerves carry information out of the brain and spinal cord the nervous system s output Neural networks networks of nerve cells that integrate sensory input and motor output where most information processing occurs They make up most of the Two Primary divisions central nervous system and the peripheral nervous system CNS made up of the brain and spinal cord Contains over 99 of all nerve cells PNS network of nerves that connect the brain and the spinal cord functions bring information to and from the brain and spinal cord and to carry out the commands of the CNS to execute various muscular and glandular chemical messengers Pathways in the Nervous System networks processes brain Divisions of the Nervous System activities 2 major divisions Somatic nervous system Sensory nerves convey information from the skin and muscles to the CNS about conditions such as pain and temperature cid 127 Motor nerves tell muscles what to do Autonomic nervous system take messages to and from the body s internal organs monitoring processes like breathing heart rate and digestion Sympathetic nervous system arouses the body to mobile it for action involved in experience of stress Para sympathetic nervous system calms the body Stress As It Relates To The Nervous System Stress the body s response to stressors circumstances and events that threaten individuals and tax their coping abilities Stress Response Begins with the flight or flight reaction one of the functions of the sympathetic nervous system cid 127 mobilizes the body s physiological resources to prepare the organism to deal with threats to survival Noticeable in the feeling of your heart pounding and hands sweating Release of corticosteroids powerful stress hormones allow us to focus our attention on what needs to be done now Acute stress momentary stress that occurs in response to life experiences Chronic stress stress that goes on continuously can lead to permanent autonomic nervous system arousal over time it can break down the nervous system Neurons Two types of cells in the nervous system neurons and glial cells Neurons nerve cells that handle the information processing function cid 127 mirror neurons are activated when we preform an action but also when we watch someone else preform the same task May play a role in empathy and cid 127 Glial cells provide support nutritional benefice and other functions in the nervous system Keep neurons running smoothly and outnumber them about 10 1 Neurons are developed early in life but their shape size and connections can change throughout their life span aka Plasticity understanding of others Specialized cell structure Every neuron has 3 parts Cell body contains the nucleus directs the manufacture of substances that the neuron needs for growth and maintenance Dendrites treelike fibers projecting from the neuron receive information and orient it toward the neuron s cell body Axon par of the neuron that carries information aaa from the cell body towards the other cells cid 127 most are encased by a myelin sheath which consists of a layer of cells containing fat They insulate axons and speed up transition of nerve impulses cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 A disorder associated with the myelin sheath is Multiple Sclerosis MS which causes hardening of the myelin sheath disruption the flow of information through neurons The development of the myelin sheath can be likened to the evolution of interstate highways as cities grew As the brain got larger it became necessary for information to travel over longer distances thus the myelin sheath came about Semipermeable membranes cover the surface of neurons The Neural Impulse cid 127 cid 127
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