Autonomic Nervous System (ANS) - Anatomy and Physiology

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 I nvoluntary nervous system a/k/a vegetative system

4. Divisions Sympathetic THORACO – LUMBAR OUTFLOW Parasympathetic CRANIO – SACRAL OUTFLOW

5. 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.

6. REFLEX ARC

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

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

9. LIMBIC SYSTEM

10. 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

11. 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

12. 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

13. Brain Stem Reticular formation. Gigantocellular nucleus. Parvocellular nuclei. Visceral nuclei of cranial nerves

14. Nuclei Of Cranial Nerves

15. 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.

16. Peripheral part All autonomic nerves & ganglia NO NERVE IN THE BODY IS TOTALLY AUTONOMIC

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

18. Physiological Effects Organs with ONLY SYMPATHETIC INNERVATIONS Sweat Glands, Adrenal Medulla, Erector Pili & Many Blood Vessels

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

20. PARA VERTEBRAL OR SYMPATHETIC CHAIN GANGLIA PREVERTEBRAL OR COLLATERAL GANGLIA TERMINAL OR PERIPHERAL GANGLIA

21. 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

22. Autonomic neurotransmitters

23. Cholinergic receptors

24. Adrenergic receptors Alpha receptors Beta Receptors

25. ACTIONS OF EACH SYSTEM

26. Reflexes Baroreceptor reflex

27. Functions HOMEOSTASIS PREPARE FOR FACING SITUATIONS SECRETIONS FROM GLANDS

28. SYMPATHETIC

29. PARASYMPATHETIC

30. Drugs – CHOLINERGIC SYSTEM

31. DRUGS – ADRENERGIC SYSTEM

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

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

34. 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

35. 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 )

36. 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

37. Dysregulated ANS Depression Schizophrenia Panic disorder and many other disorders

38. 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

39. 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

40. Anxiety and Panic disorders Low HRV, Decreased cardiac V agal 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 Elevated CSF or urinary NA metabolite Blunted ACTH responses

41. S chizophrenia 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,