CHAPTER 18 AUTONOMIC NERVOUS SYSTEM

Somatic nervous system (SNS)

PROCESSES THAT ARE CONTROLLED CONSCIOUSLY

INVOLVES VISION, HEARING, TOUCH, PROPRIOCEPTION ETC

CONTROLS SKELETAL MUSCLES

AUTONOMIC NERVOUS SYSTEM (ANS)

REGULATES PROCESSES DURING UNCONSCIOUSNESS TO MAINTAIN HOMEOSTASIS

RESPONDS TO VISCERAL SENSORY INPUTS

SENDS IMPULES TO CARDIAC MUSCLES, SMOOTH MUSCLES, AND GLANDS

MOTOR NEURON IN SNS

A SINGLE LOWER MOTOR NEURON AXON EXTENDS FROM THE SPINAL CORD TO SKELETAL MUSCLE FIBERS

THE MOTOR NEURON HAS A LARGE MYELINATED AXON AND RELEASES ACETTLCHOLINE TO STIMULATE MUSCLE

MOTOR NEURON IN ANS

A TWO NEURON CHAIN INNERVATES INVOLUNTARY MUSCLES AND GLANDS

PREGANGLIONIC AND GANGLIONIC NEURONS

PREGANGLIONIC NEURON

CELL BODY IN THE BRAIN OR SPINAL CORD

THIN, MYELINATED NEURON

EXTENDS TO SECOND NEURON AND EXCITES IT THROUGH ACETYLCHOLINE

GANGLIONIC NEURON

THIN, UNMYELINATED NEURON

EXTENDS TO EFFECTOR CELLS

THEY EXCITE OR INHIBUT THE EFFECTOR CELL WITH ACETYLCHOLINE OR NOREPINEPHRINE

PARASYMPHATHETIC DIVISION ( PNS )

HELPS CONSERVE ENERGY AND REPLENISH NUTRIENTS

REST AND DIGEST

SYMPATHETIC DIVISION ( SNS)

PREPARES BODY FOR EMERGENCIES

INCREASES ALERTNESS AND MAKES NUTRIENTS AVAILABLE FOR USE

FIGHT OR FLIGHT

AUTONOMIC TONE

SUSTAINED ACTIVITY IN SYMPHATHETIC AND PARASYMPHATHETIC DIVISIONS SETS AUTONOMIC TONE THAT REGULATES TARET ORGANS

DUAL INNERVATION

RECEIVE INPUT FROM BOTH SYMPHATHETIC AND PARASYMPHATHETIC DIVISIONS

THEY CAN OPPOSE OR COOPERATE

EXAMPLE OF DUAL INNERVATIONS - OPPOSE

PARASYMPHATHETIC - SLOWS HEART

SYMPHATHETIC - SPEEDS IT UP

EXAMPLE OF DUAL INNERVATIONS - COOPERATICE

IN MALE SEXUAL RESPONSE

PARASYMPHATHETIC - ERECTION

SYMPHATHETIC - EJACULATION

LENGTH OF AXONS IN PARASYMPHATHETIC

PREGANGLIONIC - LONG

POSTGANGLIONIC - SHORT `

LENGTH OF AXONS IN SYMPHATHETIC

PREGANGLIONIC - SHORT

POST GANGLIONIC - LONG

LOCATION OF GANGLIA PARASYMPHATHETIC

GANGLIA ARE IN OT CLOSE TO THE EFFECTORS

LOCATION OF GANGLIA SYMPHATHETIC

GANGLIA ARE NEAR THE SPINAL CORD

PARASYMPHATHETIC DIVISION TERMED CARNIOSACRAL DIVISION

BECAUSE PREGANGLIONIC NEURONS ARE HOUSED IN THE BRAINSTEM NUCLEI AND LATERAL GRAY MATTER OF THE S2-S4 SPINAL CORD SEGMENTS

GANGLIONIC NEURONS ARE IN

TERMINAL GANGLIA - CLOSE TO TARGET ORGAN

OR

INTRAMURAL GANGLIA - IN WALL OF TARGET ORGAN

WHICH CRANIAL NERVES ARE PART OF PARASYMPHATHETIC DIVISION

CN 3 - OCULOMOTOR

CN 7 - FACIAL

CN 9 - GLOSSOPHARYNGEAL

CN 10 - VAGUS

SYMPHATHETIC DIVISION IS ALSO KNOWN AS

THORACOLUMBAR DIVISION

PREGANGLIONIC NEURON CELL BODIES ARE HOUSED IN

LATERAL HORNS OF T1 THROUGH L2

SYMPHATHETIC IS MORE

COMPLEX THAN PARASYMPHATHETIC DIVISION