Autonomic nervous system

Physiology of Autonomic Nervous System

1. Autonomic Nervous System Prof. Dr. Rashid Mahmood

2. 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 2 Autonomic Nervous System Importance: Controls of all visceral functions of body Pharmacology Medicine Examination

3. Objectives Goal/Aim: To give the understanding of the physiology of Autonomic Nervous System (ANS) To describe the physiologic anatomy of Sympathetic and Parasympathetic nervous system. To classify the receptors of ANS, and relate them with the functions of ANS To describe the functions of Sympathetic and Parasympathetic nervous system. To list the neurotransmitters secreted at the at nerve endings of ANS. To list the components of Visceral reflex Arc and give examples. To tell the correlation of adrenal medulla w ith ANS 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 3

4. Control of body functions Nervous system Hormones Skeletal muscles Visceral functions Somatic NS Autonomic NS 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 4

5. MCQ 1 Regarding Autonomic outflow and Autonomic nerve fibers Sympathetic outflow is from T-1 to S-3. In the parasympathetic nervous system the axons of postganglionic neurons are usually longer than those of preganglionic neurons In case of sympathetic nervous system all the preganglionic nerves synapse in the sympathetic chain ganglia. Sympathetic nervous system is part of afferent division of the peripheral nervous system Sympathetic fibers leave the spinal nerve through White Ramus Communicans to enter the sympathetic chain 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 5

6. Organization of Nervous System 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 6

7. Autonomic Nervous System Visceral functions Heart GIT Urinary Bladder 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 7

8. Preganglionic and postganglionic neurotransmitter 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 8

9. Visceral Reflexes Components of Visceral Reflex 1 2 3 4 5 6 7 Ganglion on the way of efferent nerve 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 9

10. Autonomic Nervous System Higher control: Spinal cord Brain Stem Hypothalamus Limbic System 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 10

11. Divisions of Autonomic nervous system Sympathetic nervous system Parasympathetic nervous system 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 11

12. Sympathetic Division 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 12 Notes: 4 possible routes of sympathetic nerve after entering corresponding sympathetic chain ganglion (paravertebral ganglion): 1. synapse & come out at the same level in Grey RC to accompany corresponding spinal nerve 2. Come out without synapse & synapse in collateral (prevertebral) ganglion outside sympathetic chain ganglion 3. Go up inside sympathetic chain & synapse in cervical ganglia before coming out 4. Go down inside sympathetic chain & synapse below L2 before coming out Spinal cord Ventral horn Spinal nerve Leave spinal N. thru White RC Sympathetic chain

13. 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 13 Sympathetic Division

14. Parasympathetic Division 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 14

15. Organization of Autonomic NS 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 15

16. MCQ 1 Regarding Autonomic outflow and Autonomic nerve fibers Sympathetic outflow is from T-1 to S-3. In the parasympathetic nervous system the axons of postganglionic neurons are usually longer than those of preganglionic neurons In case of sympathetic nervous system all the preganglionic nerves synapse in the sympathetic chain ganglia. Sympathetic nervous system is part of afferent division of the peripheral nervous system Sympathetic fibers leave the spinal nerve through White Ramus Communicans to enter the sympathetic chain E 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 16

17. MCQ 2 Regarding Neurotransmitters and Characteristics of Autonomic Nervous System Acetylcholinesterase is the chemical transmitter at the neuromuscular junction. Noradrenalin is chemical transmitter at all neuromuscular junctions in autonomic nervous system GnRH ( Gonadotrophin Releasing Hormone) is a hormone, not a neurotransmitter The characteristic of the autonomic nervous system is that it exerts either excitatory or inhibitory effect on its Effector organs Sympathetic nervous system is always excitatory 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 17

18. Basic Characteristics Cholinergic & Adrenergic (Noradrenergic) Fibers

19. Sympathetic Parasympathetic Cholinergic Cholinergic Cholinergic Adrenergic Cholinergic Sweat Glands, Piloerecror Muscle, A few Blood Vessels 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 19

20. 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 20

21. 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 21

22. MCQ 2 Regarding Neurotransmitters and Characteristics of Autonomic Nervous System Acetylcholinesterase is the chemical transmitter at the neuromuscular junction. Noradrenalin is chemical transmitter at all neuromuscular junctions in autonomic nervous system GnRH (Gonadotrophin Releasing Hormone) is a hormone, not a neurotransmitter The characteristic of the autonomic nervous system is that it exerts either excitatory or inhibitory effect on its Effector organs Sympathetic nervous system is always excitatory 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 22 D

23. MCQ 3 Which of the following statements is NOT TRUE concerning the Autonomic Nervous system Nicotinic receptors are a type of cholinergic receptors Sacral outflow of parasympathetic nervous system is from S-2 to S-4 Parasympathetic nerve fibers have a ganglion close to or in the organ which they innervate Limbic system is involved in the control of Autonomic Nervous System Acetylcholine is the chemical transmitter at all neuromuscular junctions in autonomic nervous system 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 23

24. Autonomic receptors

25. N1 N2 N2 N2 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 25

26. Adrenergic Receptors 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 26

27. Function of the autonomic nerves is determined by the type of receptor 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 27

28. 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 28 General outlay of ANS Sherwood

29. Autonomic receptors 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 29 Receptor Type Neurotransmitter Affinity Effector(s) with Receptor Type Effect on Effector Cholinergic Nicotinic   ACh from autonomic preganglionic fibers All autonomic postganglionic cell bodies; adrenal medulla Excitatory ACh from motor neurons Motor end plates of skeletal muscle fibers Excitatory Muscarinic Ach from parasympathetic postganglionic fibers Cardiac muscle, smooth muscle, glands Excitatory or inhibitory, depending on effector Adrenergic α 1 Greater affinity for NE than for E Most sympathetic target tissues Excitatory α 2 Grater affinity for NE than for E Digestive organs Inhibitory β1 Equal affinity for NE and for E Heart, Kidney (Renin release), Fat cells Excitatory β2 Affinity for E only Arterioles, Uterus, UB , intestines, bronchioles Inhibitory 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

30. MCQ 3 Which of the following statements is NOT TRUE concerning the Autonomic Nervous system Nicotinic receptors are a type of cholinergic receptors Sacral outflow of parasympathetic nervous system is from S-2 to S-4 Parasympathetic nerve fibers have a ganglion close to or in the organ which they innervate Limbic system is involved in the control of Autonomic Nervous System Acetylcholine is the chemical transmitter at all neuromuscular junctions in autonomic nervous system E 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 30

31. Autonomic Functions 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 31

32. Sympathetic functions 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 32

33. Parasympathetic functions 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 33

34. Autonomic functions 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 34

35. Autonomic functions Organ Parasympathetic Sympathetic EYE Miosis Near Accommodation Mydriasis( α receptors) Opposite HEART ↓ Heart rate ↓ force of contraction ↓ Conduction of velocity Opposite (ß-1 receptors) BLOOD VESSELS Dilation ? Alpha receptors: Constriction ß-2 receptors : Dilatation e.g. Coronary arteries, skeletal muscles

36. Organ Parasympathetic Sympathetic Lungs Muscle contraction ↑ secretion Opposite( ß-2) GIT Stomach, Intestine ↑ Motility ↑ Secretions Sphincters relaxed Gall Bladder/Ducts: Contraction Opposite URINARY BLADDER Muscle Contraction Sphincter relaxed Opposite MTABOLISM Anabolism Catabolism ( ß receptors) ↑ glycogenolysis ↑ lipolysis ↑ BMR

37. Organ Parasympathetic Sympathetic Kidney Nil ↑ Renin Mental activity Nil ↑ Skeletal Muscle Nil ↑ Glycogenolysis ↑ Stretch

38. Autonomic Functions Opposite Excitatory/Inhibitory (Exception: Salivary Glands) Parasympathetic: Localized Sympathetic: Diffuse 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 38

39. 39 Function of Adrenal Medulla Catecholamines Epinephrine (Adrenaline): 80% Norepinephrine (Noradrenalin): 20% 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood

40. Self-Study Topics Value of dual autonomic supply Denervation Hypersensitivy Autonomic control areas in brain stem and hypothalamus Sympathetic and parasympathetic tone Mass discharge vs. Localized response “Alarm” or “stress” response Autonomic reflexes frequency of stimulation required for full activation Differences between functions of epinephrine and norepinephrine 40 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood

41. EOLA Which of the types of autonomic fibers release acetylcholine (Ach)? Would a drug that interferes with Ach action at nicotinic receptors block the influence of the parasympathetic nervous system, the sympathetic nervous system, or both, at effector organs? How about for a drug that interferes with Ach action at muscarinic receptors? Name some organs that are innervated only by sympathetic nerves and not by the parasympathetic nerves In which organs actions of sympathetic and parasympathetic activity are not antagonistic? Answers : All preganglionic , parasympathetic postganglionic, a few postganglionic sympathetic e.g Sweat glands Both, It will block only parasympathetic actions Blood vessels (most arterioles and veins), Sweat glands Salivary glands 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 41 Feedback

42. Thank You 18-Dec-17 Autonomic Nervous System | © Prof. Dr. Rashid Mahmood 42