Autonomic Nervous System - Anatomy and Physiology

1. AUTONOMIC NERVOUS SYSTEM
ANATOMY AND PHYSIOLOGY
Chair person : Student :
Dr Mahesh Desai Dr Chetan K Ganteppanavar
Prof and HOD,
Dept of Psychiatry,
KIMS, Hubballi

2. ORGANIZATION

3. INTRODUCTION
 Greek : autos – self & nomos – control
 Involuntary nervous system
 a/k/a vegetative system

4. Divisions
 Sympathetic
THORACO – LUMBAR OUTFLOW
 Parasympathetic
CRANIO – SACRALOUTFLOW

9. SOMATIC ANS
Afferent neuron terminate in
dorsal horn
Afferent neuron terminate in
intermediolateral horn
Interneuron terminates in
ventral horn
Interneuron terminates in
autonomic ganglia
Efferent neuron cell body in
ventral horn
Efferent neuron cell body in
autonomic ganglia
Neurotransmitter – Ach Neurotransmitter – Ach & NE
Activity – excitation Activity – Excitation & inhibition
Always voluntary. Always Involuntary.
Innervates skeletal muscles Innervates smooth muscle,
cardiac muscle , secretory glands.

10. REFLEX ARC

11. ORGANIZATION
 Cerebral hemisphere
 Brain stem
 Spinal cord
 Peripheral part of ANS

12. Cerebral Hemisphere
 Limbic system
 Prefrontal cortex
 Hypothalamus – Master of ANS with limbic
cortex being equally important
 Thalamus

13. LIMBIC SYSTEM

15. HYPOTHALAMUS
 paraventricular nucleus is the most important
 dorsomedial nucleus
 lateral hypothalamic area – CVS control, satiety,
feeding and also has some role in insulin release
 posterior hypothalamic nucleus
 mammillary nucleus

16. Disorders of the Central
Autonomic Control
 Autonomic Dysreflexia : Spinal injury above
C6 : dramatic increases in blood pressure are
provoked by inappropriate stimuli over
bladder
 Riley-Day Syndrome : decreased tearing and
sensitivity to pain and absent fungiform
papillae on the tongue : Episodic abdominal
crises and fever

17.  Sudden Infant Death Syndrome :
developmental defect in the central
autonomic network of the brainstem involved
with respiratory drive : An abrupt increase in
facial skin temperature and episodes of
apnea

18. Brain Stem
 Reticular formation.
1. Gigantocellular
nucleus.
2. Parvocellular
nuclei.
 Visceral nuclei of
cranial nerves

19. Nuclei Of Cranial Nerves

20. Spinal Cord
 Intermediolateral grey
column of spinal cord
 Sympathetic : T-1 to L-3
 Parasympathetic :
Cranial part – cranial nerves –
III, VII, IX, X
Spinal cord : S-2 to S-4.

21. Peripheral part
 All autonomic nerves & ganglia
 NO NERVE INTHE BODY ISTOTALLY
AUTONOMIC

22.  PREGANGLIONIC NEURON : axon is
myelinated type B fiber
 POSTGANGLIONIC NEURON : axon is
unmyelinated type C fiber

23. Physiological Effects
 Organs with ONLY SYMPATHETIC
INNERVATIONS
 Sweat Glands,
 Adrenal Medulla,
 Erector Pili &
 Many BloodVessels

24. Sympathetic motor ANS
DESTINATIONS
 Terminate in the ganglia.
 Travel up & down & then terminate.
 Pass without synapsing & terminate in
prevertebral ganglia.

25. PARAVERTEBRAL OR
SYMPATHETIC CHAIN
GANGLIA
PREVERTEBRAL OR
COLLATERAL
GANGLIA
TERMINAL OR
PERIPHERAL
GANGLIA

26. PARASYMPATHETIC DIVISION
 CRANIAL NERVES - II,VII, IX , X
 TECTAL OR MIDBRAIN LEVEL –
 Edinger-westphal nucleus of ill cranial nerve
 Fibres end in the ciliary ganglion
 Sphincter pupillae and ciliary muscie

27. Autonomic neurotransmitters

28. Cholinergic receptors

32. Adrenergic receptors
 Alpha receptors
 Beta Receptors

36. ACTIONS OF EACH SYSTEM

37. Reflexes
 Baroreceptor reflex

40. Functions
 HOMEOSTASIS
 PREPARE FOR FACING SITUATIONS
 SECRETIONS FROM GLANDS

41. SYMPATHETIC

42. PARASYMPATHETIC

44. Drugs – CHOLINERGIC SYSTEM

45. DRUGS – ADRENERGIC SYSTEM

47. Autonomic failure
 Primary : Unknown cause
 Secondary : Due to systemic illness like
Diabetes

48. Clinical Features
 CVS – Orthostatic hypotension , tachycardia.
 Sudomotor – anhidrosis, heat intolerance.
 GIT – constipation , diarrhea & dysphagia.
 Urinary – nocturia, frequency, urgency,
incontinence & retention.
 Reproductive – erectile & ejaculation failure

49. ANS AND PSYCHIATRY
 SOCIAL ENGAGEMENT SYSTEM : Neural
regulation of the striated muscles of the face
and head : mediated by the myelinated vagus
 Also has control from cortex and brain stem
 functions from birth and rapidly develops

50. Muscles of face
 Eyelid opening (e.g. Looking)
 Facial muscles (e.g. Emotional expression) ;
 Middle-ear muscles (e.g. Extracting human
voice from background noise) ;
 Muscles of mastication (e.g.Ingestion) ;
 Laryngeal and pharyngeal muscles
(e.G.Vocalizationand language) ;
 Head-turning muscles (e.g. Social gesture
andorientation)

51. Social Nervous System –
third branch of ANS ?
 In the ANS, the parasympathetic system is
the oldest, reflecting the survival needs of a
primitive passive feeders.
 The sympathetic nervous system is a later
development, for possible survival responses

52. Dysregulated ANS
 Depression
 Schizophrenia
 Panic disorder and many other disorders

53. Heart rate variability
 Sensitive measure of autonomic system
function
 utilized as a tool to assess the effect of
psychopathology and disease
 balance between sympathetic and para
sympathetic input to the heart

54. Mood disorders and Depression
 Cardiac patients with more severe depression exhibit
less HRV compared to those with less severe
depression
 Treatment of depression tends to be accompanied
by an increase in HRV
 Vagal nerve stimulation (VNS) has been reported to
successfully improve affect in treatment-resistant
depression
 Strong link between sympathovagal dysregulation
and symptoms of depression

55. Anxiety and Panic disorders
 Low HRV,
 Decreased cardiacVagal tone,
 Elevated sympathetic heart rate control
 Adapt slowly to repeated stimuli
 Respond excessively to moderate stimuli
 Poorly regulated NA system with occasional bursts
of activity
 ElevatedCSF or urinary NA metabolite
 BluntedACTH responses

56. Schizophrenia and Manic BD
 There is a decrease in parasympathetic
activity independent of medication effects in
schizophrenia.
 Hyper excitability in both the sympathetic
and the parasympathetic division
 Reduction in HRV,
 Reduced parasympathetic activity,