Chapter 15 - Section 15.1 - General Properties of the Autonomic Nervous System - Before You Go On - Page 560: 1

The autonomic nervous system (ANS) and the somatic motor system are two distinct divisions of the peripheral nervous system, and they differ both functionally and anatomically in several ways: 1. Function: - Autonomic Nervous System (ANS): The ANS is responsible for regulating involuntary physiological functions that occur without conscious control. It controls processes such as heart rate, digestion, respiratory rate, blood pressure, and glandular secretion. The ANS can be further divided into the sympathetic and parasympathetic divisions, which have opposing effects on various bodily functions, maintaining homeostasis. - Somatic Motor System: The somatic motor system controls voluntary muscle movements. It enables conscious control over skeletal muscles, allowing you to perform activities like walking, talking, and picking up objects. 2. Target Organs: - Autonomic Nervous System (ANS): The ANS primarily targets smooth muscles, cardiac muscles, and glands throughout the body. It controls functions like the contraction of blood vessels, regulation of heart rate, and digestion. - Somatic Motor System: The somatic motor system exclusively controls skeletal muscles attached to bones and is responsible for voluntary body movements. 3. Neural Pathways: - Autonomic Nervous System (ANS): The ANS consists of two motor neurons in its pathway. The preganglionic neuron originates in the central nervous system (CNS) and synapses with a postganglionic neuron located in peripheral ganglia. The postganglionic neuron then innervates the target organ. - Somatic Motor System: The somatic motor system has a single motor neuron that extends from the CNS directly to the skeletal muscle it innervates. 4. Neurotransmitters: - Autonomic Nervous System (ANS): The ANS uses both acetylcholine and norepinephrine as neurotransmitters. Acetylcholine is typically released by preganglionic neurons, whereas norepinephrine is released by postganglionic neurons in the sympathetic division and acetylcholine in the parasympathetic division. - Somatic Motor System: The somatic motor system predominantly uses acetylcholine as the neurotransmitter to stimulate skeletal muscle contraction at the neuromuscular junction. 5. Conscious Control: - Autonomic Nervous System (ANS): The ANS operates involuntarily and is not under conscious control. It functions automatically to maintain internal homeostasis. - Somatic Motor System: The somatic motor system operates under voluntary control. You can consciously decide to move specific skeletal muscles. In summary, the autonomic nervous system is responsible for regulating involuntary physiological processes in the body, such as maintaining internal balance, while the somatic motor system controls voluntary muscle movements that are consciously initiated. These two systems have distinct anatomical pathways, target organs, neurotransmitters, and levels of conscious control.

The autonomic nervous system (ANS) and the somatic motor system are two distinct divisions of the peripheral nervous system, and they differ both functionally and anatomically in several ways: 1. Function: - Autonomic Nervous System (ANS): The ANS is responsible for regulating involuntary physiological functions that occur without conscious control. It controls processes such as heart rate, digestion, respiratory rate, blood pressure, and glandular secretion. The ANS can be further divided into the sympathetic and parasympathetic divisions, which have opposing effects on various bodily functions, maintaining homeostasis. - Somatic Motor System: The somatic motor system controls voluntary muscle movements. It enables conscious control over skeletal muscles, allowing you to perform activities like walking, talking, and picking up objects. 2. Target Organs: - Autonomic Nervous System (ANS): The ANS primarily targets smooth muscles, cardiac muscles, and glands throughout the body. It controls functions like the contraction of blood vessels, regulation of heart rate, and digestion. - Somatic Motor System: The somatic motor system exclusively controls skeletal muscles attached to bones and is responsible for voluntary body movements. 3. Neural Pathways: - Autonomic Nervous System (ANS): The ANS consists of two motor neurons in its pathway. The preganglionic neuron originates in the central nervous system (CNS) and synapses with a postganglionic neuron located in peripheral ganglia. The postganglionic neuron then innervates the target organ. - Somatic Motor System: The somatic motor system has a single motor neuron that extends from the CNS directly to the skeletal muscle it innervates. 4. Neurotransmitters: - Autonomic Nervous System (ANS): The ANS uses both acetylcholine and norepinephrine as neurotransmitters. Acetylcholine is typically released by preganglionic neurons, whereas norepinephrine is released by postganglionic neurons in the sympathetic division and acetylcholine in the parasympathetic division. - Somatic Motor System: The somatic motor system predominantly uses acetylcholine as the neurotransmitter to stimulate skeletal muscle contraction at the neuromuscular junction. 5. Conscious Control: - Autonomic Nervous System (ANS): The ANS operates involuntarily and is not under conscious control. It functions automatically to maintain internal homeostasis. - Somatic Motor System: The somatic motor system operates under voluntary control. You can consciously decide to move specific skeletal muscles. In summary, the autonomic nervous system is responsible for regulating involuntary physiological processes in the body, such as maintaining internal balance, while the somatic motor system controls voluntary muscle movements that are consciously initiated. These two systems have distinct anatomical pathways, target organs, neurotransmitters, and levels of conscious control.