Chapter 15 – Study Guide                                    ( a.k.a.= also known as )

somatic motor neuron neurotransmitters – ACh (acetylcholine) only

autonomic motor neuron neurotransmitters – ACh or NE (norepinephrine a.k.a. noradrenaline)

2 principal branches of ANS have opposing actions

                sympathetic NS = thoracolumbar division / outflow (T1-12, L1-2)

                                vertebral chain (a.k.a. sympathetic trunk, a.k.a. paravertebral) ganglia

                                prevertebral (a.k.a. collateral) ganglia

                parasympathetic NS = craniosacral division / outflow (S2-4, brainstem)

                                terminal (a.k.a. intramural) ganglia

autonomic plexuses – tangled networks of sympathetic & parasympathetic neurons

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SYMPATHETIC

O---<   ACh (nicotinic)          O---<   NE (adrenergic)            (most effectors)

O---<       ACh (nicotinic)                        O---<       ACh (muscarinic)                    (sweat glands, a few effectors)

 

PARASYMPATHETIC

O---<   ACh (nicotinic)          O---<   ACh (muscarinic)         (effectors)

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cholinergic neurons – release ACh,                  cholinergic receptors – bind ACh

                (cholinergic) nicotinic receptors – sympathetic & parasympathetic neurons and also motor end plates

                (cholinergic) muscarinic receptors – parasympathetic effectors (and very few sympathetic effectors = sweat glands)

 

adrenergic neurons – release NE,                      adrenergic receptors – bind NE

                (adrenergic) a 1, b 1 receptors – binding of NE generally produces excitation of effector

                (adrenergic) a 2, b 2 receptors – binding of NE generally produces inhibition of effector

 

agonist – binds to & activates receptor (mimics neurotransmitter)

antagonist – binds to & blocks receptor (prevents neurotransmitter from having effect)

hypothalamus – regulates balance between sympathetic tone & parasympathetic tone

 

SYMPATHETIC STIMULATION                                                   PARASYMPATHETIC STIMULATION

[ α or β (adrenergic) receptors ]                                                         [ muscarinic (cholinergic) receptors ]

FIGHT or FLIGHT                                                                              FEED or BREED / REST or DIGEST

 

INHIBITS DIGESTION                                                                     PROMOTES DIGESTION

inhibits digestive enzyme secretion  & digestive juices                promotes digestive enzyme secretion & digestive juices

decreases GI motility                                                                          increases GI motility

contracts sphincters

increases activity / release of hormones & enzymes                    increases glycogen synthesis

                for breaking down glycogen & triglycerides

 

INHIBITS URINATION                                                                    PROMOTES URINATION

increases ADH - antidiuretic hormone

relaxes bladder wall                                                                            contracts bladder wall

contracts sphincter                                                                              relaxes sphincter

 

INCREASES WORK OF HEART                                                    DECREASES WORK OF HEART

increases heart rate & force of contraction                                    decreases heart rate & force of contraction

 

INCREASES WORK OF LUNGS                                                     DECREASES WORK OF LUNGS

dilates airways                                                                                     constricts airways

 

PUPIL DILATES                                                                                 PUPIL CONSTRICTS

 

                                                                                                                INCREASES SEXUAL ACTIVITY

                                                                                                                vasodilation in clitoris and penis