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Chapter 14

Autonomic Nervous System

Lecture 21

Marieb’s HumanAnatomy and

Physiology

Marieb Hoehn

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Autonomic (Visceral) Nervous System

CNS PNS

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Autonomic Nervous System

• functions without conscious effort• controls visceral (squishy!) activities• regulates smooth muscle, cardiac muscle, and glands

Two Main Divisions

• sympathetic – prepares body for fight or flight situations

• parasympathetic – prepares body for rest and digest activities

Third Division – Enteric Nervous System (ENS)

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Somatic vs. Autonomic Nervous Systems

Figure from: Marieb, Human Anatomy & Physiology, Pearson, 2013

Dual

Overview of Sympathetic NS

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From: http://home.comcast.net/~wnor/thoraxlesson5.htm

From: http://www.nature.com/gimo/contents/pt1/fig_tab/gimo6_F4.html

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Sympathetic Division of ANS

Figure from: Saladin, Anatomy & Physiology, McGraw Hill, 2007

Effectors in muscles and body wall

Effectors in head and thoracic cavity

*

*

*

(T5 – T12)

Paravertebral ganglion

NOTE: Arrangement of nerves creates DIVERGENCE

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Sympathetic Division of the ANS

SYMPATHETIC (Thoracolumbar outflow)

Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

Fight or Flight

“E” situations Emergency Embarrassment Excitement Exercise

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Parasympathetic(Craniosacral outflow)

SalivationLacrimationUrinationDigestionDefecation

3 decreases - Heart rate - Airway diameter - Pupil size (constrict)

“REST AND DIGEST”

Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004

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Autonomic Plexuses

Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004

Sympathetic collateral (prevertebral) ganglia

Autonomic plexuses contain sympathetic and parasympathetic postganglionic fibers

(Solar plexus)

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Autonomic Neurotransmitters

You should know which neurotransmitters are released, and the locations where they are released

= always excitatory in ganglia

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Actions of Autonomic Neurotransmitters

• depend on receptor

Cholinergic receptors• bind acetylcholine• nicotinic

• excitatory• muscarinic

• excitatory or inhibitory

Adrenergic receptors• bind norepinephrine• alpha (Types 1 and 2)

• different responses on various effectors

• beta (Types 1 and 2)• different responses on various effectors

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Control of Autonomic Activity

Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

Sympathetic

Parasympathetic

Sympathetic and Parasympathetic

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Review of Autonomic Nervous System

Branch of ANS PARASYMPATHETIC SYMPATHETIC

GeneralFunction

* “rest and digest”* (SLUDD); Salivation, lacrimation, urination, digestion, defecation* 3 decreses; ↓ heart rate, ↓ pupil size, ↓ airway diameter

* “fight or flight” * E situations: Emergency, exercise, embarassment, excitement

Origin of Preganglionic fiber

cranial region of brain or sacral region of spinal cord (craniosacral outflow)

thoracic or lumbar region of spinal cord (thoracolumbar outflow)Divergence for widespread activation of body

Location of Ganglia

within or near effector organ alongside or in front of spinal cord (paravertebral ganglia; collateral ganglia)

NTx secreted by postganglionicfiber

acetylcholine Norepinephrine (some acetylcholine; sweat glands, smooth muscle on blood vessels, brain)

Good summary chart to know