Ch. 11 The Autonomic and Motor Systems

Ch. 11 The Autonomic and Motor Systems - Ch. 11 The...

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Ch. 11 The Autonomic and Motor Systems I) The Autonomic Nervous System a) Parasympathetic more active during rest, sympathetic more active during activity b) Called autonomic because it functions at a subconscious level c) Dual Innervation in the Autonomic Nervous System i) BOTH branches of the ANS innervate most organs, called dual innervation;  HOWEVER, their functions are generally opposite ii) Sympathetic coordinates fight-or-flight iii) At rest both systems are active but the parasympathetic dominates d) Anatomy i) Consists of efferent pathways containing two neurons arranged in a series that  communicate between the CNS and the effector organ ii) The neurons communicate in peripheral structures called  autonomic ganglia ; a  single preganglionic neuron generally synapses with several postganglionic neurons iii) Other neurons located entirely within each ganglion called  intrinsic neurons  modulate  the flow of information to the target organs iv) Sympathetic (1) Because the preganglionic emerge from the thoracic and lumbar portions of the  cord, the sympathetic is sometimes called the thoracolumbar division (2) The preganglionic neurons originate in a region of gray matter called the  lateral  horn (3) Pre- and post- anatomically arranged in three patterns (a) Most common, pregang have short axons that originate in the lateral horn and  exit via the ventral root; (i)  immediately after the roots merge to form the nerve, the axon of the  pregang leaves the nerve via a branch called the  white ramus  to enter  one of the sympathetic ganglia; most of the post- return to the spinal  nerve via the  gray ramus  and then travel to effector (ii) The various sympathetic ganglia are linked together to form structures  that run parallel to the column on either side called  sympathetic chains which help in the widespread fight-or-flight actions (b) Important exception to the aforementioned is a group of long preganglionic 
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This note was uploaded on 04/07/2008 for the course APK 2105 taught by Professor Brooks during the Spring '07 term at University of Florida.

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Ch. 11 The Autonomic and Motor Systems - Ch. 11 The...

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