Autonomic Nervous System

1. Autonomic Nervous System بسم ﷲ الرحمن الرحيم Abu ahmed 2014

2. Anatomic organization of the nervous system Nervous system Central nervous system Enclosed in bony cavities (skull, vertebral column) Peripheral nervous system Outside bony cavities (nerves)

3. Organization of The Nervous System Central Nervous System Peripheral Nervous System Autonomic Nervous System Somatic Nervous System Sympathetic Parasympathetic

5. Division of nervous system

6. Neuron • Is the functional unit of nervous system. • Function: conduct information.

7. Neuron

8. Neuron

9. Comparison btw Somatic & Autonomic

10. ANS SOMATIC N.S

11. Somatic and Autonomic Nervous System

12. Comparison of Somatic and Autonomic Efferent Pathways

14. Principle of nervous system function(the reflex arc) Control center efferent afferent receptor effector

15. The nervous system Somatic functions Visceral functions Voluntary functions

16. Anatomical divisions of the ANS • Sympathetic nervous system • Parasympathetic nervous system • Enteric nervous system (responsible for regulation of digestive functions.).

17. Origins of the sympathetic and parasympathetic division • Sympathetic nervous system • Emerge from thoracic and lumbar spinal cord • Thoraco-lumbar out flow (T1-L3) • Parasympathetic nervous system • Emerge from brain and sacral spinal cord • Cranio-sacral out flow (III,VII,IX&X pluse S2-S4) • Cranial nerves that carry parasysmpathetic fibers: • Occulomotor (III), facial (VII), glossopharngeal (IX) and vagus (X)

23. Pathways of the sympathetic & parasympathetic division • Two neurons from CNS to effectors: • Preganglionic neuron (in CNS) • Postganglionic neuron (outside CNS) • In ganglia

24. From CNS to effectors effector Preganglionic neuron Postganglionic neuron CNS

25. Comparison between autonomic fibers • Sympathetic: • Preganglionic short (Meylinated type B fibers) • Postganglionic long (Unmeylinated type C fibers) • Ganglion near to the CNS • Parasympathetic: • Preganglionic long (Meylinated type B fibers) • Postganglionic very short (unmeylinated type C fibers) • Ganglion inside the organ

27. Parasympathetic Postganglionic fibers Preganglionic fibers effector Postganglionic fibers Preganglionic fibers Sympathetic CNS

28. Sympathetic ganglia • Paravertebral sympathetic chain. • Orcollateral ganglia : away from sympathetic chain Eg. Cervical ganglia, mesenteric and coeliacganglia.

29. collateral sympathetic ganglia Paravertebral sympathetic chain

31. Sympathetic nerve supply to the head • From extension of sympathetic chain in the neck: • Inferior, middle and superior cervical ganglia • In the eye causes: • Elevation of upper eye lid • Dilatation of pupil of the eye • In the face causes sweating

32. Horner’s syndrome • Sympathetic supply to one side of the face is interrupted so patient will have on affected side of the face: • Constriction of the pupil • Drooping of upper eye lid • Sweating absent • Dilated blood vessels

33. Horner’s syndrome

34. Adrenal Medulla • The adrenal medulla is considered a modified sympathetic ganglion that lost its postganglionic axons. • Released hormones (catecholamine) directly into the blood.

35. General functions of ANS بسم ﷲ الرحمن الرحيم Abu ahmed 2014

36. General functions of ANS • SYMPATHETIC • Emergency responses (fight or flight). • Catabolic system. • PARASYMPATHETIC • Rest and Digest. • Vegetative functions. • anabolic system.

39. Responses to Increased Sympathetic Activity 1. Increases cardiac output. 2. Increases blood pressure. 3.Mobilizes fats for energy. 4. Raise blood glucose. 5. Increased respiratory rate and respiratory passage ways dilate.

40. 6. Sweat glands activated. 7. Vasoconstriction of skin blood vessels. 8. constrict sphincters. 9. Pupil dilation. 9. Increases mental alertness.

41. Responses to Increased Levels of Parasympathetic Activity Decreased: metabolic rate. heart rate and blood pressure. Increased: salivary and digestive glands secretion. motility and blood flow in digestive tract. Urination and defecation stimulation.

42. Neurotransmitters and receptors • Autonomic neurons classified to: • Cholinergic neurons ( neurons that release acetylcholine) • Adrenergic neurons (neurons that release Noradrenaline)

43. Autonomic receptors • Classified to : • Cholinergic receptors. • Adrenergic receptors.

44. Cholinergic neurons • Cholinergic neurons (release Ach). • Released by: 1. All preganglionic neurons (SMP & PARA). 2. All postganglionic parasympathetic neurons.

45. 3.Some postganglionic sympathetic neurons (those supplying sweat glands blood vessels of the skeletal muscles pilomotor muscle).

46. acetylcholine released and cross the synaptic cleft, combines to receptors. • Its action is terminated by the acetylcholinesterase , which converts it to acetate and choline. Therefore no acetylcholine diffuses to plasma.

47. Synthesis and degradation of acetylcholine Choline acetyltransferase choline Acetyl-co A acetylcholine + Acetylcholine esterase acetate + choline

48. Autonomic neurotransmiters • Parasympathetic • Sympathetic Ach Ach NA Ach Ach Exceptions: Sweat glands Skeletal muscle vessels Ach

49. SOMATIC NERVOUS SYSTEM Skeletal muscle ACh AUTONOMIC NERVOUS SYSTEM Heart Sm. mus. Glands Sympathetic ACh NE Sweat glands ACh ACh E, NE ACh Ad. M.   Heart Sm. mus. Glands Parasympathetic ACh ACh Neurotransmitters