PART 5 THE Autonomic Nervous system Unit 3 Communication and Control

Nervous System Divisions

A. INTRODUCTION

The Autonomic Nervous System Autonomic = visceral A subdivision of the PNS Sympathetic, parasympathetic and enteric divisions Regulates Glands Smooth muscle Cardiac muscle ANS activities are automatic (involuntary)

iCLICKER Your client is prescribed a medication that targets the autonomic nervous system. Which effector will NOT be directly affected? Cardiac muscle Glands Smooth muscle Skeletal muscle

Review of SNS Voluntary and reflexive movements If somatic neurons stop = all communication with effector stops

The Autonomic Nervous System ANS components similar to those in SNS Sensory Receptor (intero, chemo, mechano) Autonomic Sensory Neuron Integrating Center Effector Autonomic (preganglionic)Motor Neuron Autonomic (postganglionic) Motor Neuron Table 15.1

iCLICKER How many neurons are in an autonomic motor pathway ? 1 2 3 4

ANS Focuses on Efferent System Autonomic pathways = two motor neurons connecting SC  effector Preganglionic Motor Neuron SC or brainstem (cell body)  ganglion Myelinated Postganglionic Motor Neuron Ganglion (cell body)  effector Unmyelinated NOTE: SNS has uninterrupted synapse

B. ANATOMY OF THE ANS Most organs have dual innervation INTRODUCTION Body movement results from alternating contraction (shortening) and relaxation of muscles; the skeletal system provides leverage and a supportive framework for this movement. Most organs have dual innervation

Sympathetic Nervous System

Sympathetic Nervous System Autonomic motor neurons Spinal cord Autonomic ganglion Sympathetic preganglionic neuron (myelinated) Sympathetic postganglionic neuron (unmyelinated) Effectors: glands, cardiac muscle, smooth muscle (e.g., in urinary bladder)

Sympathetic Nervous System Exception to typical SANS system

Sympathetic Chains

Sympathetic Ganglia Right sympathetic trunk ganglion CELIAC GANGLION SUPERIOR MESENTERIC GANGLION INFERIOR MESENTERIC GANGLION Right sympathetic trunk ganglion Anterior view

Figure 15.2 Structure of the Sympathetic ANS

iCLICKER Which nerves carry sympathetic motor output? cranial nerves spinal nerves cranial nerves and spinal nerves

iCLICKER Which neurotransmitter is released by sympathetic postganglionic neurons? acetylcholine epinephrine norepinephrine both b) and c)

Parasympathetic Nervous System

Parasympathetic Nervous System Autonomic ganglion ACh Spinal cord Parasympathetic preganglionic neuron (myelinated) Parasympathetic postganglionic neuron (unmyelinated) Effectors: glands, cardiac muscle, smooth muscle

Terminal ganglia

Figure 15.3 Structure of the Parasympathetic ANS

iCLICKER Which nerves carry parasympathetic motor output? cranial nerves spinal nerves cranial nerves and spinal nerves

iCLICKER Which neurotransmitter is released by parasympathetic postganglionic neurons? acetylcholine epinephrine norepinephrine both b) and c)

Enteric Nervous System Nerves & ganglia Wall of GI tract, pancreas, gallbladder GI tract needs to respond to environmental stimuli to fnc (like skin) ENS usually fnc independently from CNS

ANS Receptors

ANS Receptors

iCLICKER Which receptor is found on effector cells of the parasympathetic nervous system? alpha beta muscarinic nicotinic

C. PHYSIOLOGY OF THE ANS

Autonomic Reflexes Interoreceptor Sensory Neuron PreganglionicNeuron Integrating Center Effector Postganglionic Neuron

Pupillary Light Reflex

Pupillary Light Reflex

The Effect of Higher Brain Centers on ANS Functions

D. FUNCTIONS OF THE ANS

Sympathetic Responses Four Es

Parasympathetic Responses SLUDD