3. AUTONOMIC NERVOUS SYSTEM

6. Terminologies for ANS Anatomically: – Thoracolumber outflow(T1-L2) – Craniosacral outflow(III, VII, IX, X, S1-S3) Physiologically: – Sympathetic – Para sympathetic Pharmacologically: – Adrenergic – Cholinergic

8. Somatic Vs ANS

9. Organization of ANS Central component: 1.Brainstem 2.Hypothalamus 3.Spinal cord Peripheral component: 1.Nerves 1.Sympathetic 2.Parasympathetic Ganglia: 1.Vertebral 2.Paravertebral 3.Terminal

11. Role of ANS Maitain homeostasis by maintaining a dynamic antagonism b/w sympathetic & parasympathetic divisions of ANS Parasympathetic (D) – Digestion – Defecation – Diuresis Sympathetic (E) – Exercise – Excitement – Emergency – Embarrassment

12. Sympathetic system: – Short preganglionic fiber – Long postganglionic fiber Parasympathetic system: – Long preganglionic fiber – Short post ganglionic fiber

15. Autonomic neurotransmitters Acetylcholine (Cholinergic fibers) Acetylcholine (Cholinergic fibers) – All preganglionic fibers – All parasympathetic postganglionic fibers Adrenaline (Adrenergic fibers) Adrenaline (Adrenergic fibers) – Most sympathetic postganglionic fibers

17. Receptors Acetylcholine: – Muscarinic Membranes of effecter cell – Nicotinic Synapse of pre & post ganglionic autonomic nerves Adrenaline: – Alpha Smooth muscles(contraction) – Beta Smooth muscle(relaxation)

21. Sympathetic nerve fibers in skelatal nerves Some of the sympathetic postganglionic fibers pass back from sympathetic chain These are C type fibers Control – Blood vessels – Sweat glands – Piloerector muscle 8% of fibers in skeletal nerves are sympathetic

23. Sympathetic nerve fibers in adrenal medulla Preganglionic symp. Fibers pass without synapse in adrenal medulla. Reach the specialized secretory cells which secrete epinephrine & nor epinephrine.

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26. Functions of ANS

28. Sympathetic nervous systemParasympathetic nervous system CatabolicAnabolic Increases energy expenditure of the body. Preserve energy in the body (i.e. save energy in the heart and offer it in the intestine). Prepares the body for activity, increasing the capacity to perform sever muscular effort (fight and flight) in response to stress (emergency situations). Predominates during sleep where there are continuous digestion, slow heart rate and constricted pupil. Delay onset of fatigue of contracting muscles Allow for repair and recovery of contracting muscles. Sympathetic mass stimulation is usefulParasympathetic mass stimulation is fatal.

30. Eyes Pupillary opening – Sympathetic system: Contracts meridional fibers--- pupillary dilatation – Parasympathetic system: Contracts the circular muscles---- pupillary constriction Focus of lense: – Parasympathetic: Contracts ciliary muscles---- release of tension in lense ligament---- convex---- accomodation

32. Glands Nasal, lacrimal, salivary & gastrointestinal glands Parasympathetic---- increased secretion Sympathetic ---- concentrated secretions(enzymes & mucous) Sweat glands: cholinergic sympathetic fibers-- --- increased secretion – Stimulated by centers in hypothalamus

34. Apocrine glands – Supplied by sympathetic fibers – Stimulation secretes thick, odriferous & lubricant secretion

35. GIT Parasympathetic: – Increases motility – Sphincters relax – Increased secretion of glands Sympathetic: – Strong stimulation Inhibits peristalsis Increased sphincters tone

37. (Stomach, small intestine and proximal part of large intestine) Relaxation of their walls and contraction of their sphincters leading to inhibition of digestion and delayed evacuation of their contents. (1) GIT Stimulation of glycogenolysis leading to increased blood glucose. Stimulation of fibrinogen synthesis. (2) Liver: contraction of wall and relaxation of sphincter of Oddi, helping its evacuation. (3) Gall bladder: Contraction of smooth muscles in splenic capsule and trabeculae leading to pouring of about 250 ml of stored blood into the general circulation. (4) Spleen: Sympathetic stimulation usually inhibits pancreatic secretion (both endocrine and exocrine components). (5) Pancreas: Mixed supply (vasoconstriction and vasodilatation). (6) Blood vessels Stimulation of juxta glomerular cells leading to increased renin secretion. Decrease renal blood flow. Decrease urine output. (7) Kidneys: LHCs of T 6-12 segments of spinal cord (splanchni c nerves). Collateral ganglia (celiac, superior mesenteric, aortico-renal) and terminal ganglia origin Relay SympatheticSympathetic

38. (Stomach, small intestine and proximal part of large intestine) contraction of their walls and relaxation of their sphincters enhancing both digestion and evacuation of GIT contents i.e. help deglutition, gastric motility, and peristaltic movement of GIT. (1) GIT increased hepatic bile flow. (2) Liver: Relaxation of its wall and contraction of sphincter of oddi leading to retention of bile and delayed emptying of gall bladder. (3) Gall bladder: Parasympathetic stimulation usually stimulates pancreatic secretion (both endocrine and exocrine components). (4) Pancreas: Vasodilatation. (5) Blood vessels Stimulation of gastric juice secretion (rich in HCl). Stimulation of alkaline mucus secretion from Bruner's glands in the duodenum. (6) Glands: Dorsal motor nucleus of the vagus Terminal ganglia in the wall of abdominal organs origin Relay Parasympatheti c

39. Action of sympathetic on Suprarenal medulla Origin: LHCs of T 10,11 segments of spinal cord. * SRM has special character being supplied by sympathetic preganglionic nerve fibers (with no postganglionic nerve fibers) which relay there on special neurosecretory cells (chromaffin cells). * Stimulation of sympathetic nerves to SRM releases large quantities of adrenaline (80%) and noradrenaline (20%) into the circulating blood, being carried to all body tissues. These hormones has prolonged action due to their slow clearance from the circulation. - Adrenaline acts more on metabolic actions of the body while noradrenaline acts more on blood vessels. - In stress conditions, SRM acts together with sympathetic nervous system (sympatho-adrenal system).

40. Heart (CVS) Sympathetic Increased HR Increased FOC Increased resistance Vasoconstriction in abdomin & skin Parasympathetic Decreased HR Decreased FOC Decreased resistance Little effect on vessels

42. ParasympatheticSympathetic Dorsal Motor nucleus of the vagusLHCs of upper 4 or 5 thoracic segments of spinal cord Origin Terminal ganglia in the wall of the heart and lung Cervical ganglia (superior, middle and inferior) and upper 4 thoracic ganglia Relay Parasympathetic stimulation decreases the effectiveness of the heart as a pump i.e. decreasing the rate, force of heart contraction, conduction velocity, excitability, cardiac metabolism and O 2 consumption.  Coronary vessels : Direct effect is vasodilatation. Vagal stimulation inhibits cardiac work with less production of metabolites. Thus the coronary vessels indirectly constrict (vasoconstriction). a) Sympathetic stimulation increases the effectiveness of the heart as a pump i.e. increasing the rate, force of heart contraction, conduction velocity, excitability, cardiac metabolism and O 2 consumption. b) Coronary vessels: Direct effect is vasoconstriction. Indirectly the coronary vessels dilate as a result of accumulation of metabolites of the stimulated heart. Action on the heart  N.B.: Parasympathetic does not supply the ventricles.

43. a) Motor to the smooth muscles of the bronchial tree resulting in bronchoconstriction. b) Stimulate the mucus secretion of the air passages. c) Vasodilatation of the pulmonary blood vessels. a) inhibition of the smooth muscles of the bronchial tree resulting in bronchodilatation b) inhibition of the mucus secretion of air passages. c) vasoconstriction of the pulmonary blood vessels. Action of the lungs SYMPETHETICPARASYMPETHETIC

44. Actions on Pelvis

46. ParasympatheticSympathetic Sacral segments 2, 3, 4 (preganglionic forms pelvic nerve) LHCs of L1, L2, L3 segments of spinal cord. Origin Terminal ganglia in the wall of the pelvic organs Collateral ganglia (inferior mesenteric or hypogastric ganglia) and terminal ganglia Relay Contraction of its wall and relaxation of internal urethral sphincter leading to micturition. relaxation of its wall and contraction of internal urethral sphincter leading to urine retention. Action on Urinary bladder Contraction of its wall and relaxation of internal anal sphincter leading to defecation. relaxation of its wall and contraction of internal anal sphincter leading to retention. Action of the rectum a) Vasodilatation of the blood vessels of the pelvic viscera including that of sex organs leading to erection of the penis, clitoris, etc. and congestion of the labia. So, the pelvic nerve is named as the nervus erigenus. b) Secretory to the seminal vesicles, prostate and other accessory glands. a)Contraction of smooth muscles in the walls of seminal vesicle, epididymis, vas deferens and ejaculatory duct leading to ejaculation of semen. b)Vasoconstriction of blood vessels of pelvic viscera including those of external sex organs leading to shrinkage of penis. Action of male sex organs a) Vasoconstriction of blood vessels of external sex organs leading to shrinkage of clitoris. Action of female sex organs

47. SympatheticParasympathetic (I) Antagonistic functions: 1- Pupil:Mydriasis.Miosis. 2- Air passages.bronchodilatation.bronchoconstriction. 3- Heart  rate  rate  contraction  contraction  coronary blood flow  coronary blood flow 4- GIT: - Wall - Sphincter - Blood vessels relaxation contraction vasoconstriction contraction relaxation vasodilatation 5- Rectum retention of faecesdefecation 6- Urinary bladderretention of urineMicturition 7- blood vesselsVasoconstrictionvasodilatation (II) Synergistic function: (During salivary secretion) Trophic salivary secretionTrue salivary secretion (little, viscid, rich in enzymes)(large in volume, watery, rich in electrolytes) N.B.: Augmented secretion Stimulation of sympathetic to salivary glands after parasympathetic stimulation leads to augmented secretion due to active squeeze of acini as a result of sympathetic stimulation of myoepithelial cells surrounding acini (which are filled with secretions by parasympathetic stimulation). (III) Cooperative functions: (During sexual intercourse) *Contraction of vas deference, seminal vesicle, ejaculatory duct; producing ejaculation of semen. *Shrinkage of penis and clitoris due to vasoconstriction *Secretory to seminal vesicle and prostate. *Erection of penis and clitoris due to vasodilatation.