AUTONOMIC NERVOUS SYSTEM
Functions:
Contraction and relaxation of
smooth muscles
Function of all exocrine glands
Heart rate
Some metabolic processes
AUTONOMIC NERVOUS SYSTEM
 sympathetic NS
 ncl. intermediolateralis in
T1 – L2 segments of spinal cord
= thoracolumbar system
 paravertebral ganglia
(tr. sympathicus) and
prevertebral ganglia
 neurotransmitters
 pregangl. – acetylcholine
 postgangl. – norepinephrin
(ex. sweat glands and
piloerector muscle)
 parasympathetic NS
 parasympathetic nuclei
of CN III, VII, IX, X
 segments S2 – S4
= craniosacral system
 ganglia near the target
organ
 neurotransmitter
acetylcholine
Sympathetic system
Catabolic reaction (activities that are mobilized
during emergency and stress situations, “fight,
fright and flight” responses)
Parasympathetic system
Anabolic reactions (activities associated with
conservation and restoration of body resources,
“rest and digest” responses)
Central autonomic network
Modulation of ANS
 from brain cortex
 tr. corticoreticularis → tr. reticulospinalis → preganglionic
neurons
 from hypothalamus
 tr. hypothalamotegmentalis
 tr. mammillotegmentalis
 from hypothalamus and limbic forebrain
 FLD → dorsolateral tegmentum
 CC – from amygdalar complex
 → hypothalamus
 → PAG – coordination of somatic and autonomic response to
behavior and defensive reaction → preganglionic neurons of
S and PS divisions
Descendent modulatory pathways
 fasciculus longitudinalis dorsalis (FLD)
 fasciculus telencephalicus medialis (medial forebrain
bundle MFB)
 tr. mammillotegmentalis
Hypothalamus
Nuclei of the anterior part
 ncl. paraventricularis
 stimulation of parasympathetic system
Stimulation of the anterior part of hypothalamus
 miosis
 decrease in heart rate and blood pressure
 dilation of cutaneous arteries
 increase in peristalsis and secretion in the GIT
Hypothalamus
Nuclei of the posterior part
 ncl. mammillaris and hypothalamicus post.
 stimulation of sympathetic system
Stimulation of the posterior part of hypothalamus
 mydriasis
 increase in heart rate and blood pressure
 constriction of cutaneous arteries
 decrease in peristalsis and secretion in the GIT
 erection of hairs
PUPILARY LIGHT REFLEX
 a reflex that controls the diameter
of the pupil, in response to the
intensity of light (luminance) that
falls on the retina of the eye
 mydriasis: dilation of the pupil
 miosis: constriction of the pupil
ACCOMMODATION
Illustrations were copied from:
Neuroscience Online, the Open-Access Neuroscience
Electronic Textbook
Department of Neurobiology and Anatomy
University of Texas Medical School at Houston