1. Autonomic nervous system By Pak Int’l Med College Pak Int’l Med College Peshawar:::: Peshawar::::

4. The Autonomic nervous system is the portion of the nervous system that controls most visceral functions of the body The Autonomic nervous system is the portion of the nervous system that controls most visceral functions of the body It is primarily concerned with the regulation of visceral or vegetative functions of the body, so it is called vegetative or involuntary nervous system It is primarily concerned with the regulation of visceral or vegetative functions of the body, so it is called vegetative or involuntary nervous system This system helps to control arterial pressure, gastrointestinal motility, sweating, body temperature and many other activities some of which are controlled almost entirely and some only particularly by the autonomic nervous system. This system helps to control arterial pressure, gastrointestinal motility, sweating, body temperature and many other activities some of which are controlled almost entirely and some only particularly by the autonomic nervous system. One of the most striking characteristic of the autonomic nervous system is the rapidity and intensity with which it can change visceral functions. One of the most striking characteristic of the autonomic nervous system is the rapidity and intensity with which it can change visceral functions.

5. General organization of autonomic nervous system. The autonomic nervous system is activated mainly by centers located in the spinal cord, brainstem and hypothalamus. Also portions of the cerebral cortex especially of the limbic cortex, can transmit signal to the lower centers and in this way influence autonomic controls. The autonomic nervous system is activated mainly by centers located in the spinal cord, brainstem and hypothalamus. Also portions of the cerebral cortex especially of the limbic cortex, can transmit signal to the lower centers and in this way influence autonomic controls. The autonomic nervous system also often operates through visceral reflexes. The autonomic nervous system also often operates through visceral reflexes.

6. Division of ANS From anatomical and physiological point of view, the autonomic nervous system is divided into two divisions. 1.Sympathetic division 2. Parasympathetic division.

7. It is otherwise called thoracolumber outflow because the preganglionic neurons are situated in lateral gray horns of 12 thoracic and first two lumber segments of spinal cord. The fibers arising from here are known as preganglionic fibers. The preganglionic fibers leave the spinal cord through anterior nerve root and white rami communicants and terminates in the postganglionic neurons, which are situated in the sympathetic ganglia. It is otherwise called thoracolumber outflow because the preganglionic neurons are situated in lateral gray horns of 12 thoracic and first two lumber segments of spinal cord. The fibers arising from here are known as preganglionic fibers. The preganglionic fibers leave the spinal cord through anterior nerve root and white rami communicants and terminates in the postganglionic neurons, which are situated in the sympathetic ganglia. Sympathetic division supplies smooth muscles fibers of all the visceral organs such as blood vessels, heart, lungs, glands, GIT etc Sympathetic division supplies smooth muscles fibers of all the visceral organs such as blood vessels, heart, lungs, glands, GIT etc

8. Sympathetic ganglia The ganglia of sympathetic division are classified into three groups. The ganglia of sympathetic division are classified into three groups. 1. Paravertebral or sympathetic chain ganglia 1. Paravertebral or sympathetic chain ganglia 2. Prevertebral or collateral ganglia 2. Prevertebral or collateral ganglia 3. Terminal or peripheral ganglia 3. Terminal or peripheral ganglia

9. Paravertebral or sympathetic chain ganglia Paravertebral or sympathetic chain ganglia are arranged in a segmental fashion along the anterolateral surface of vertebral column. Paravertebral or sympathetic chain ganglia are arranged in a segmental fashion along the anterolateral surface of vertebral column. The ganglia on either side of the spinal cord are connected with each other by longitudinal fibers to form the sympathetic chains. The ganglia on either side of the spinal cord are connected with each other by longitudinal fibers to form the sympathetic chains. Both the chains extend from skull to coccyx Both the chains extend from skull to coccyx Ganglia of the sympathetic chain (trunk) on each side are divided into four groups. Ganglia of the sympathetic chain (trunk) on each side are divided into four groups. 1. Cervical ganglia. 1. Cervical ganglia. 2. Thoracic ganglia. 2. Thoracic ganglia. 3. Lumber ganglia. 3. Lumber ganglia. 4. Sacral ganglia. 4. Sacral ganglia.

10. Prevertebral or collateral ganglia Prevertebral ganglia are situated in thorax, abdomen and pelvis in relation to aorta and its branches Prevertebral ganglia are situated in thorax, abdomen and pelvis in relation to aorta and its branches The Prevertebral ganglia are The Prevertebral ganglia are 1. Celiac ganglion 1. Celiac ganglion 2. Superior mesenteric ganglion 2. Superior mesenteric ganglion 3. Inferior mesenteric ganglion 3. Inferior mesenteric ganglion The Prevertebral ganglia receives preganglionic fibers from T 5 to L 2 segments. The Prevertebral ganglia receives preganglionic fibers from T 5 to L 2 segments. The postganglionic fibers from these ganglia supply the visceral organs of thorax, abdomen and pelvis. The postganglionic fibers from these ganglia supply the visceral organs of thorax, abdomen and pelvis.

11. Terminal or peripheral ganglia. Terminal ganglia are situated within or close to structures innervated by them. Terminal ganglia are situated within or close to structures innervated by them. Heart, bronchi, pancreas and urinary bladder are innervated by the terminal ganglia Heart, bronchi, pancreas and urinary bladder are innervated by the terminal ganglia

12. Segmental distribution of the SNF The sympathetic fiber from cord segment are from The sympathetic fiber from cord segment are from T 1 generally passes up the chain to the head T 1 generally passes up the chain to the head T 2 in the neck T 2 in the neck T 3,T 4,T 5 and T 6 into the thorax T 3,T 4,T 5 and T 6 into the thorax T 7,T 8,T 9,T 10 and T 11 into the abdomen T 7,T 8,T 9,T 10 and T 11 into the abdomen T 12,L 1,L 2 into the legs. T 12,L 1,L 2 into the legs.

13. Sympathoadrenergic system Sympathoadrenergic system is a functional phylogenetics unit that includes sympathetic division and adrenal medulla Sympathoadrenergic system is a functional phylogenetics unit that includes sympathetic division and adrenal medulla Adrenal medulla is a modified sympathetic ganglion. Adrenal medulla is a modified sympathetic ganglion. Since adrenal medulla and sympathetic division develop from same neural crest, their secretion and functions are almost the same Since adrenal medulla and sympathetic division develop from same neural crest, their secretion and functions are almost the same Any increase in sympathetic activity increases the secretion of Catecholamine from adrenal medulla Any increase in sympathetic activity increases the secretion of Catecholamine from adrenal medulla

14. The parasympathetic division of ANS is otherwise called craniosacral outflow because, the fibers of this division arise from brain and sacral segments of spinal cord. The parasympathetic division of ANS is otherwise called craniosacral outflow because, the fibers of this division arise from brain and sacral segments of spinal cord. The cranial portion of parasympathetic division in brainstem innervates the blood vessels of the head and neck and many thoracoabdominal visceral organs. The cranial portion of parasympathetic division in brainstem innervates the blood vessels of the head and neck and many thoracoabdominal visceral organs. The sacral portion in sacral segments of the spinal cord innervates the smooth muscles forming the walls of viscera and the glands such as large intestines, liver, spleen, kidneys, bladder, genitalia etc The sacral portion in sacral segments of the spinal cord innervates the smooth muscles forming the walls of viscera and the glands such as large intestines, liver, spleen, kidneys, bladder, genitalia etc

16. Cranial nerves of Parasympathetic division The cranial nerve of the parasympathetic division are. The cranial nerve of the parasympathetic division are. 1. Oculomotor (iii) nerve 1. Oculomotor (iii) nerve 2. Facial (vii) nerve 2. Facial (vii) nerve 3. Glossopharyngeal (ix) nerve 3. Glossopharyngeal (ix) nerve 4. Vagus (x) nerve 4. Vagus (x) nerve The fibers of sacral outflow arise from second to fourth sacral (s 1 to s 2 ) segments of spinal cord and occasionally the first and fourth sacral nerves The fibers of sacral outflow arise from second to fourth sacral (s 1 to s 2 ) segments of spinal cord and occasionally the first and fourth sacral nerves Thus the preganglionic fibers of parasympathetic division arise from the neurons situated at three different levels Thus the preganglionic fibers of parasympathetic division arise from the neurons situated at three different levels 1. Tectal or midbrain level (iii cranial nerve) 1. Tectal or midbrain level (iii cranial nerve) 2. Bulbar level or bulbar outflow (vii, ix, x cranial nerve) 2. Bulbar level or bulbar outflow (vii, ix, x cranial nerve) 3. Sacral outflow (sacral nerves) 3. Sacral outflow (sacral nerves)

18. Tectal or midbrain level. Tectal or midbrain level. In ciliary's ganglion Bulbar level or bulbar outflow. Bulbar level or bulbar outflow. Fibers of vii cranial nerve supply the lacrimal, nasal, sub maxillary and sublingual glands Fibers of ix cranial nerve supply the parotid gland Fibers of x cranial nerve supply visceral organs of the body About 75 % of all parasympathetic nerve fibers are in Vagus nerves passing entire thoracic and abdominal regions of the body About 75 % of all parasympathetic nerve fibers are in Vagus nerves passing entire thoracic and abdominal regions of the body

19. Sacral outflow The preganglionic fibers arise from anterior gray horn cells of 2 nd, 3 rd and 4 th sacral segments of spinal cord and form the pelvic nerve. The preganglionic fibers arise from anterior gray horn cells of 2 nd, 3 rd and 4 th sacral segments of spinal cord and form the pelvic nerve. The fibers end on the postganglionic neurons which are situated on or near the visceral organs. The fibers end on the postganglionic neurons which are situated on or near the visceral organs. The sacral parasympathetic fibers supply those visceral organs which are not supplied by Vagus. The sacral parasympathetic fibers supply those visceral organs which are not supplied by Vagus.

20. Neurotransmitter of ANS The different nerve fibers of ANS execute the functions by releasing some neurotransmitter substance The different nerve fibers of ANS execute the functions by releasing some neurotransmitter substance

21. Neurotransmitter substance

23. Those fibers that secrete acetylcholine are said to be cholinergic. Those fibers that secrete acetylcholine are said to be cholinergic. Those that secrete nor epinephrine are said to be adrenergic, a term derived from adrenaline, which is an alternate name for epinephrine Those that secrete nor epinephrine are said to be adrenergic, a term derived from adrenaline, which is an alternate name for epinephrine

25. Sympathetic fibers Preganglionic fibers: Acetylcholine (ach) Preganglionic fibers: Acetylcholine (ach) Postganglionic noradrenergic fibers: Nor adrenaline Postganglionic noradrenergic fibers: Nor adrenaline Postganglionic cholinergic fibers: Ach Postganglionic cholinergic fibers: Ach The postganglionic sympathetic cholinergic nerve fibers supply sweat gland and blood vessels in heart and in skeletal muscle. The postganglionic sympathetic cholinergic nerve fibers supply sweat gland and blood vessels in heart and in skeletal muscle.

26. Parasympathetic fibers Preganglionic fibers: ACH Postganglionic fibers: ACH

27. Types of acetylcholine receptors Acetylcholine activates mainly two types of receptors. Acetylcholine activates mainly two types of receptors. They are called They are called Muscarinic and nicotinic receptors. Muscarinic and nicotinic receptors. The reason for these names is that muscarine, a poison from toadstools, activates only Muscarinic receptors and will not activate nicotinic receptor, whereas nicotine activates only nicotinic receptor ;Acetylcholine activates both of them The reason for these names is that muscarine, a poison from toadstools, activates only Muscarinic receptors and will not activate nicotinic receptor, whereas nicotine activates only nicotinic receptor ;Acetylcholine activates both of them

28. Adrenergic receptors. These are also two major types of adrenergic receptors, These are also two major types of adrenergic receptors, ALPHA and BETA receptors. ALPHA and BETA receptors. Alpha: alpha 1 and alpha 2 Alpha: alpha 1 and alpha 2 Beta: beta 1 beta 2 and beta 3 Beta: beta 1 beta 2 and beta 3

29. Adrenergic receptors and function ALPHA ALPHA 1. Vasoconstriction 2. Iris dilation 3. Intestinal relaxation 4. Intestinal sphincter contraction 5. Pilomotor contraction 6. Bladder sphincter contraction 7. Inhibits neurotransmitter release BETA 1. Vasodilatation 2. Cardioacceleration 3. Increased myocardial strength 4. Intestinal relaxation 5. Bronchodilator 6. Calorigenesis 7. Glycogenolysis