Chapter_11_Autonomic - Chapter 11 Autonomic & Motor...

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Functional composition of the PNS. I. The Autonomic Nervous System Dual Innervation of the Autonomic Nervous System Primary function – regulate organs to maintain homeostasis Parasympathetic and sympathetic activites tend to oppose each other o Parasympathetic nervous system – rest Top and bottom of spinal region No ganglian o Sympathetic nervous system – fight or flight Originates in the different part of the spinal cord than parasympathetic Ganglian o Fig 11.1 Anatomy of the Autonomic Nervous System Effector organs o Cardiac muscle o Smooth muscle o Glands o Adipose tissue Autonomic Neurons 2 neurons in the effector pathway. 1 st neuron has its cell body in gray matter of barin or spinal cord Preganglionic neuron. Synapses with 2 nd neuron within an autonomic ganglion which extends to synapse with effector organ Postganglionic neuron. Anatomy of Autonomic Pathways Organs with Dual Innervation Most visceral organs are innervated by both sympathetic and parasympathetic fibers Antagonistic effects: Actions counteract each other. Heart rate Complementary: Produce similar effects Salivary gland secretion Cooperative: Cooperate to produce a desired effect Micturition; erection & ejaculation
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Sympathetic Division KNOW FIG 11.1 Myelinated preganglionic exit spinal cord in ventral roots at T1(thoracic) to L2 (lumbar) levels Most travel along spinal nerves to paravertebral ganglia to synapse with postganglionic neurons May lead to mass activation of systems Sympathetic Division Mass activation: divergence and convergence cause the SNS to be activated as a unit Divergence and convergence cause. Axons of postganglionic neurons are
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Chapter_11_Autonomic - Chapter 11 Autonomic & Motor...

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