Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PNS: Autonomic Nervous System  Motor subdivision of the PNS  Consists only of motor nerves  Also known as the involuntary nervous system  Regulates activities of cardiac and smooth muscles and glands  Two subdivisions  Sympathetic division  Parasympathetic division

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PNS: Comparison of Somatic and Autonomic Nervous Systems (P. 266) Figure 7.27

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PNS: Differences Between Somatic and Autonomic Nervous Systems  Nerves  Somatic: one motor neuron  Autonomic: preganglionic and postganglionic neurons  Effector organs  Somatic: skeletal muscle  Autonomic: smooth muscle, cardiac muscle, and glands

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PNS: Differences Between Somatic and Autonomic Nervous Systems  Neurotransmitters  Somatic: always use acetylcholine  Autonomic: use acetylcholine, epinephrine, or norepinephrine

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.28 PNS: Anatomy of the Autonomic Nervous System (P. 267)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PNS: Anatomy of the Parasympathetic Division  Preganglionic neurons located in the brain stem and S 2 through S 4 levels of the spinal cord  AKA ”Craniosacral” division  Always uses acetylcholine as a neurotransmitter

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PNS: Anatomy of the Sympathetic Division  Preganglionic neurons located in T 1 through L 2 of spinal cord  AKA “thoracolumbar” division  Short pre-ganglionic neuron and long post- ganglionic neuron transmit impulse from CNS to the effector  Norepinephrine and epinephrine are neurotransmitters to the effector organs

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PNS: Autonomic Functioning  Parasympathetic  Most active when body is at rest  “Housekeeping” activities  Maintains daily necessary body functions  Promotes normal digestion & elimination  Conserves energy  Remember as the “D” division  digestion, defecation, and diuresis (urination)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PNS: Autonomic Functioning  Sympathetic  Response to unusual stimulus  “Fight or flight” division  Takes over to increase activities  Heart rate, blood pressure, blood glucose levels, dilates bronchioles of lungs, dilates pupils, perspiration, goose bumps  Remember as the “E” division  Exercise, excitement, emergency, and embarrassment

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Table 7.3 (1 of 2) Effects of the Sympathetic and Parasympathetic Divisions of the ANS

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Effects of the Sympathetic and Parasympathetic Divisions of the ANS Table 7.3 (2 of 2)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Tracking Down CNS Problems  EEG  Used to diagnose & localize brain lesions, tumors, & abscesses; brain waves are unique  CT & MRI Scans  Allow most tumors, intracranial lesions, plaques, & areas of dead brain tissue to be ID’ed  CT scans are the 1 st used to determine if stroke was caused by a clot or a bleed

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Tracking Down CNS Problems  PET Scans  Can localize lesions that generate epileptic seizures & being used to diagnose Alzheimer’s disease  Cerebral Angiography  Injection of dye to make arteries stand out on X- ray; used for patients with TIA (warning stroke)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Development Aspects of the Nervous System  The nervous system is formed during the first month of embryonic development  Any maternal infection can have extremely harmful effects  The brain has the highest metabolic rate in the body  The hypothalamus is one of the last areas of the brain to develop  Controls body temp  Premature babies have trouble maintaining body temp because hypothalamus isn’t developed

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Development Aspects of the Nervous System  No more neurons are formed after birth, but growth and maturation continues for several years  The brain reaches maximum weight as a young adult  As you age...  Sympathetic NS becomes less efficient  Constricts blood vessels & lack of oxygen leads to senility