autonomic nervous system handout
TRANSCRIPT
CLASSIFICATION OF THE NERVOUS SYSTEM1. Central Nervous System (CNS)• includes the brain and spinal cord• integrative and control center
2. Peripheral Nervous System (PNS)• includes the cranial and peripheral nerves• communication lines between the CNS and the rest of the body• divided into 2: afferent (sensory) and efferent (motor)
EFFERENT (MOTOR) DIVISIONA. Somatic nervous system
• voluntary• conducts impulses from CNS to skeletal muscles
B. Autonomic nervous system• involuntary• composed of nerves, ganglia, plexuses• innervates smooth muscles of viscera, cardiac muscles, blood vessels and exocrine glands• only needs very low frequency of stimulation for full activation• Functions:
1. Maintain homeostasis2. Regulates daily requirements and needs of the body without conscious control
C. Enteric NS• composed of neurons located in the walls of the GIT• consists of the myenteric plexus (Auerbach) and submucosal plexus (Meissner)• includes inputs from the sympathetic and parasympathetic nervous system
ANATOMIC DIVISION OF THE AUTONOMIC NERVOUS SYSTEM1. Sympathetic2. Parasympathetic
Rest and DigestAction is discrete and localizedNot a functional entity and never discharges as a complete systemEssential to life
Flight or FightAction is diffuse and widespreadFunctions as a unit and often discharges as a complete unit (“mass discharge”)Not essential to life
Function
AcetylcholineMuscarinic
Norepinephrine/ AChAlpha, Beta/ Muscarinic
Postganglionic Neurotransmitter Receptor
AcetylcholineNicotinic
AcetylcholineNicotinic
Preganglionic Neurotransmitter Receptor
ShortLongPostganglionic fibers
LongShortPreganglionic fibers
Organs innervatedParavertebral chainsPrevertebral ganglia
Location of Ganglia
Cranial nerves 3,7,9,10Sacral nerves 2,3,4
Thoracic (T1-T12)Lumbar (L1-L5)
Spinal roots of Origin(Outflow)
ParasympatheticSympathetic