5: The Autonomic Nervous System
- Page ID
- 117706
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- 5.1: Objectives
- This page outlines key learning objectives related to the autonomic nervous system (ANS), focusing on distinguishing between somatic and autonomic divisions, neuron origins, and anatomical differences. It includes understanding reflexes, neurotransmitters, dual innervation effects, and the autonomic control of organs.
- 5.2: Introduction
- This page discusses the nervous system's two main components: the somatic nervous system (SNS), which controls voluntary skeletal muscle movements, and the autonomic nervous system (ANS), which regulates involuntary functions such as those of cardiac and smooth muscles, and glandular tissues. While the SNS can have unconscious responses, the ANS is crucial for maintaining homeostasis by managing essential involuntary processes.
- 5.3: Comparison of Somatic and Autonomic Efferent Systems
- This page compares the somatic nervous system (SNS) and autonomic nervous system (ANS), detailing their anatomical and functional differences. The SNS connects motor neurons directly to skeletal muscles, while the ANS uses a two-neuron chain for cardiac and smooth muscles and glands. Efferent pathways also differ: SNS utilizes lower motor neurons for somatic reflexes, whereas the ANS employs preganglionic and postganglionic neurons for visceral reflexes.
- 5.4: Sympathetic Division of the Autonomic Nervous System
- This page discusses the sympathetic nervous system's role in the fight-or-flight response, detailing how it activates various organs via connections from the spinal cord. It explains the synapse between preganglionic and postganglionic neurons in sympathetic ganglia, and their influence on organs like the heart and glands.
- 5.5: Parasympathetic Division of the Autonomic Nervous System
- This page discusses the parasympathetic division, or craniosacral system, highlighting its anatomical features, including the origin of preganglionic neurons and their long fibers that connect to terminal ganglia near target organs. It regulates functions like digestion, urination, and sexual arousal using specific nerves and works alongside the sympathetic system to maintain homeostasis and adapt to bodily changes.
- 5.6: Chemical Signaling in the Autonomic Nervous System
- This page describes the autonomic nervous system's cholinergic and adrenergic synapses, their signaling molecules (ACh and NE), and receptor types. It explains the "fight or flight" response, marked by physiological changes like increased heart rate and enhanced vigilance, and its potential health risks with prolonged activation.
- 5.7: Short and Long Reflexes
- This page explains the central nervous system's role in somatic and visceral reflexes, detailing that both involve sensory and motor neurons. Somatic reflexes can be monosynaptic and occur in the spinal cord or brain stem, while visceral reflexes manage functions like digestion and heart rate. Reflexes are categorized as short (localized responses) or long (involving the CNS).
- 5.8: Dual Innervation
- This page discusses the autonomic nervous system's role in homeostasis, highlighting the interactions between its sympathetic and parasympathetic divisions. It explains how sympathetic activation (e.g., norepinephrine) increases heart rate and contraction, while parasympathetic activation (e.g., acetylcholine) decreases heart rate.
- 5.9: Autonomic Tone
- This page discusses autonomic tone, highlighting the balance between sympathetic and parasympathetic systems in body regulation. It details how parasympathetic tone can lower heart rates to 60-80 bpm, while sympathetic influence is vital for blood pressure control through vasoconstriction. Additionally, sympathetic input can increase blood flow to skeletal muscles in stress responses, with rare parasympathetic effects primarily observed in reproductive tissues for engorgement.
- 5.10: Hypothalamic Regulation of the ANS
- This page describes how the hypothalamus regulates autonomic functions by integrating neural signals and coordinating sympathetic and parasympathetic activities. It highlights important pathways, such as the median forebrain bundle and dorsal longitudinal fasciculus, which connect the hypothalamus to vital autonomic nuclei.
- 5.11: References
- This page discusses the autonomic nervous system, contrasting it with the somatic system and detailing its functions, connections, and reflexes. It references various authors and educational resources like OpenStax and StatPearls, exploring topics such as the sympathetic and parasympathetic divisions, reflex mechanisms, and anatomical structures. The text underscores the importance of the autonomic system in regulating bodily functions and responses.