Chapter 15 - Section 15.3 - Study Guide - Assess Your Learning Outcomes - Page 575: 2

The autonomic nervous system (ANS) consists of two main divisions: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). Cholinergic and adrenergic fibers are terms used to describe the neurotransmitters and receptors involved in these two divisions. 1. **Cholinergic Fibers**: - **Neurotransmitter**: The primary neurotransmitter used by cholinergic fibers is acetylcholine (ACh). - **Receptors**: Cholinergic receptors include nicotinic and muscarinic receptors. - **Functions**: - Cholinergic fibers generally promote rest and relaxation responses in the body. - They are responsible for slowing down heart rate, promoting digestion, and stimulating salivation. - Cholinergic fibers are also involved in promoting constriction of the pupils (miosis) and bronchoconstriction (narrowing of the airways). - **Locations**: - Cholinergic fibers are predominantly found in the parasympathetic nervous system (PNS). The PNS is responsible for rest and digest functions and operates during non-stressful situations. - Cholinergic fibers innervate organs such as the heart, gastrointestinal tract, and bladder. 2. **Adrenergic Fibers**: - **Neurotransmitter**: Adrenergic fibers primarily use norepinephrine (noradrenaline) as a neurotransmitter. - **Receptors**: Adrenergic receptors include alpha and beta receptors. - **Functions**: - Adrenergic fibers generally promote the "fight or flight" response in the body. - They are responsible for increasing heart rate, dilating airways, and redirecting blood flow to skeletal muscles. - Adrenergic fibers can also cause pupil dilation (mydriasis) and inhibit digestion. - **Locations**: - Adrenergic fibers are primarily found in the sympathetic nervous system (SNS). The SNS is responsible for the body's response to stress or danger and prepares it for action. - Adrenergic fibers innervate organs such as the heart, blood vessels, and the respiratory system. In summary, cholinergic fibers use acetylcholine as a neurotransmitter and are predominantly found in the parasympathetic nervous system, responsible for rest and relaxation functions. Adrenergic fibers use norepinephrine as a neurotransmitter and are primarily located in the sympathetic nervous system, responsible for the "fight or flight" response. These two systems work in a complementary manner to regulate various physiological processes and maintain homeostasis in the body.

The autonomic nervous system (ANS) consists of two main divisions: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). Cholinergic and adrenergic fibers are terms used to describe the neurotransmitters and receptors involved in these two divisions. 1. **Cholinergic Fibers**: - **Neurotransmitter**: The primary neurotransmitter used by cholinergic fibers is acetylcholine (ACh). - **Receptors**: Cholinergic receptors include nicotinic and muscarinic receptors. - **Functions**: - Cholinergic fibers generally promote rest and relaxation responses in the body. - They are responsible for slowing down heart rate, promoting digestion, and stimulating salivation. - Cholinergic fibers are also involved in promoting constriction of the pupils (miosis) and bronchoconstriction (narrowing of the airways). - **Locations**: - Cholinergic fibers are predominantly found in the parasympathetic nervous system (PNS). The PNS is responsible for rest and digest functions and operates during non-stressful situations. - Cholinergic fibers innervate organs such as the heart, gastrointestinal tract, and bladder. 2. **Adrenergic Fibers**: - **Neurotransmitter**: Adrenergic fibers primarily use norepinephrine (noradrenaline) as a neurotransmitter. - **Receptors**: Adrenergic receptors include alpha and beta receptors. - **Functions**: - Adrenergic fibers generally promote the "fight or flight" response in the body. - They are responsible for increasing heart rate, dilating airways, and redirecting blood flow to skeletal muscles. - Adrenergic fibers can also cause pupil dilation (mydriasis) and inhibit digestion. - **Locations**: - Adrenergic fibers are primarily found in the sympathetic nervous system (SNS). The SNS is responsible for the body's response to stress or danger and prepares it for action. - Adrenergic fibers innervate organs such as the heart, blood vessels, and the respiratory system. In summary, cholinergic fibers use acetylcholine as a neurotransmitter and are predominantly found in the parasympathetic nervous system, responsible for rest and relaxation functions. Adrenergic fibers use norepinephrine as a neurotransmitter and are primarily located in the sympathetic nervous system, responsible for the "fight or flight" response. These two systems work in a complementary manner to regulate various physiological processes and maintain homeostasis in the body.