The Autonomic Nervous System

The Autonomic Nervous System Controls involuntary functions through smooth muscle and cardiac striated muscle Two systems – Sympathetic and Parasympathetic Two neurones involved in response These interact in Ganglia lying close to the spine (sympathetic) or in effector organs (parasympathetic) The post-ganglionic neurone is non-myelinated and releases a specific neurotransmitter

The Sympathetic Nervous System Induces a stress or ‘fight’ reaction Nerves are stimulated in the spinal cord by incoming signals from sensory neurons A neuron runs to the spinal trunk ganglion Here it connects with an effector neuron that runs to an effector organ Interaction with the effector tissue is via a synapse using nor-adrenalin as a neurotransmitter

The Sympathetic Trunk

The Sympathetic Compared to Somatic Motor Neural Pathways

The Sympathetic Nervous System

The Parasympathetic Nervous System Primarily driven through cranial nerves especially X (ten) the vagus nerve Ganglia are present either in a target organ or adjacent to it The post-ganglionic synapse uses acetylcholine as the major neurotransmitter

The Parasympathetic Nervous System

The Autonomic Nervous System - Comparisons Parasympathetic Cranial Nerves III,VII,IX and X (vagus) Reduces Stress Acetylcholine is the principle neurotransmitter Sympathetic Series of interconnecting ganglia running down the spinal column Heightens stress - ‘Fight and Flight’

Neurotransmitters in the ANS

Outline Comparison of the Actions of the Parasympathetic and Sympathetic Nervous Systems

Summary The autonomic or visceral nervous system controls involuntary automated processes It comprises pre-ganglionic and post-ganglionic neurons and is stimulated by sensory pathways The effector systems are located at the organ level and regulate automated responses There are two sub-systems, the sympathetic and parasympathetic