Chapter 11 The Nervous System Autonomic Nervous System General Anatomy of the CNS The CNS is ul6mately responsible for everything we perceive do feel and think Coordinates the ac6vity of all our organ systems Contains about 100 billion neurons and about 100 trillion synapses all contained within the brain and spinal cord Anatomy of the Autonomic Nervous System The autonomic nervous system innervates most e ector organs and 6ssues Cardiac muscle smooth muscle blood vessels stomach reparatory pathways etc glands sweat salivary endocrine etc and adipose 6ssue Called autonomic because its func6ons at a subconscious level Anatomy of the Autonomic Nervous System The primary func6on of the ANS is to regulate the func6on of e ector organs so as to maintain homeostasis Two branches both innervate most organs and act in opposite manners and are typically most ac6ve under di erent condi6ons Parasympathe6c NS is most ac6ve rest and digest Sympathe6c NS is most ac6ve during ght or ight Anatomy of the Autonomic Nervous System The major areas of the brain that regulate autonomic func6on include the hypothalamus pons and medulla oblongata Hypothalamus elicits widespread ac6va6on of sympathe6c nervous system and regulates body temperature food intake and water balance Anatomy of the Autonomic Nervous System The major areas of the brain that regulate autonomic func6on include the hypothalamus the pons medulla oblongata Medulla Oblongata and the Pons contain cardiovascular and respiratory regulatory centers that control the heart blood vessels and smooth muscle in the respiratory airways to allow breathing Autonomic Pathways In autonomic pathways neurons transmit informa6on from the CNS to an e ector organ through ganglionic pathways Sympathe6c Nervous System Preganglionic neurons emerge from the thoracic and lumbar por6ons of the lateral horn of the spinal cord Typically they synapse onto sympathe6c ganglia that are linked together to form structures that run parallel to the spinal column on either side of it called sympathe6c chain The Most Common Pathway of Sympathe6c Fibers Sympathe6c Innerva6on of the Adrenal Gland Parasympathe6c Nervous System Preganglionic neurons of the parasympathe6c nervous system originate either in the brain stem of sacral spinal cord and terminate in ganglia located near the e ector organ Autonomic NTs and Receptors Autonomic NTs and Receptors Autonomic NTs and Receptors Atropa belladonna Autonomic Neuroe ector Junc6ons NeurotransmiUer Release from Varicosi6es Regula6on of Autonomic Func6on