Chapter 14 provides knowledge of the autonomic nervous system. In this chapter, you will learn to: Define autonomic nervous system and explain its relationship to the peripheral nervous system; compare the somatic and autonomic nervous systems relative to effectors, efferent pathways, and neurotransmitters released; compare and contrast the functions of the parasympathetic and sympathetic divisions;. | 14 The Autonomic Nervous System Autonomic Nervous System (ANS) The ANS consists of motor neurons that: Innervate smooth and cardiac muscle and glands Make adjustments to ensure optimal support for body activities Operate via subconscious control Autonomic Nervous System (ANS) Other names Involuntary nervous system General visceral motor system Central nervous system (CNS) Peripheral nervous system (PNS) Motor (efferent) division Sensory (afferent) division Somatic nervous system Autonomic nervous system (ANS) Sympathetic division Parasympathetic division Figure Somatic and Autonomic Nervous Systems The two systems differ in Effectors Efferent pathways (and their neurotransmitters) Target organ responses to neurotransmitters Effectors Somatic nervous system Skeletal muscles ANS Cardiac muscle Smooth muscle Glands Efferent Pathways Somatic nervous system A, thick, heavily myelinated somatic motor fiber makes up each pathway from the CNS to the muscle ANS pathway is a two-neuron chain Preganglionic neuron (in CNS) has a thin, lightly myelinated preganglionic axon Ganglionic neuron in autonomic ganglion has an unmyelinated postganglionic axon that extends to the effector organ Neurotransmitter Effects Somatic nervous system All somatic motor neurons release acetylcholine (ACh) Effects are always stimulatory ANS Preganglionic fibers release ACh Postganglionic fibers release norepinephrine or ACh at effectors Effect is either stimulatory or inhibitory, depending on type of receptors Skeletal muscle Cell bodies in central nervous system Peripheral nervous system Effect + + Effector organs ACh ACh Smooth muscle (., in gut), glands, cardiac muscle Ganglion Adrenal medulla Blood vessel ACh ACh ACh NE Epinephrine and norepinephrine Acetylcholine (ACh) Norepinephrine (NE) Ganglion Heavily myelinated axon Lightly myelinated preganglionic axon Lightly myelinated preganglionic axons Neuro- transmitter at effector Unmyelinated postganglionic axon Unmyelinated . | 14 The Autonomic Nervous System Autonomic Nervous System (ANS) The ANS consists of motor neurons that: Innervate smooth and cardiac muscle and glands Make adjustments to ensure optimal support for body activities Operate via subconscious control Autonomic Nervous System (ANS) Other names Involuntary nervous system General visceral motor system Central nervous system (CNS) Peripheral nervous system (PNS) Motor (efferent) division Sensory (afferent) division Somatic nervous system Autonomic nervous system (ANS) Sympathetic division Parasympathetic division Figure Somatic and Autonomic Nervous Systems The two systems differ in Effectors Efferent pathways (and their neurotransmitters) Target organ responses to neurotransmitters Effectors Somatic nervous system Skeletal muscles ANS Cardiac muscle Smooth muscle Glands Efferent Pathways Somatic nervous system A, thick, heavily myelinated somatic motor fiber makes up each pathway from the CNS to the muscle ANS pathway is a two-neuron .
