The autonomic nervous system

This presentation is focused on the introduction to the autonomic nervous system.

1. THE AUTONOMIC NERVOUS SYSTEM By Dr. sahar hafeez

2. ANS receives input from parts of the CNS that process and integrate stimuli from the body and external environment; Hypothalamus Nucleus Tractus Solitarious Reticular formation Amygdala Hippocampus Olfactory cortex

3. Functions controlled by Autonomic nervous system Control of heart rate and force of contraction Constriction and dilatation of blood vessels Contraction and relaxation of smooth muscle Visual accommodation, pupillary size Secretion from exocrine and endocrine glands

4. Sympathetic Fear and fight

5. Parasympathetic REST and digest

6. Two Divisions Sympathetic: Thoracolumbar outflow preganglionic cell bodies are located in the intermediolateral horn of the spinal cord from T1 to L2. Parasympathetic: Craniosacral outflow preganglionic cell bodies are located in the Brainstem and sacral portion of the spinal cord.

7. AUTONOMIC GANGLIA Sympathetic: Para vertebral chain of Ganglia Collateral Ganglia; celiac, superior mesenteric, inferior mesenteric, renal. Parasympathetic: Cranial nerves Ganglia; ciliary , sphenopalatine, otic , submandibular, visceral ganglia of Vagus (X CN) Pelvic Ganglia

8. Sympathetic: Short preganglionic fibers , Long postganglionic fibers Parasympathetic: Long preganglionic fibers Short postganglionic fibers

9. Autonomic NEUROTRANSMITTERS Sympathetics: Preganglionic fibers use Acetylcholine Postganglionic fibers use Epinephrine , Norepinephrine (with an exception of “pilomotor” and “ sudomotor ” fibers) Parasympathetics: Preganglionic fibers use Acetylcholine Postganglionic fibers use Acetylcholine

10. Fate of preganglionic sympathetic fibers enters the paravertebral ganglion at the level of its originating spinal nerve, and then ascends to a more superior paravertebral ganglion, where it synapses with the postsynaptic cell. enters the paravertebral ganglion at the level of its originating spinal nerve and synapses with the postsynaptic cell at that level. enters the paravertebral ganglion at the level of its originating spinal nerve, and then descends to a more inferior paravertebral ganglion, where it synapses with the postsynaptic cell. enters the paravertebral ganglion at the level of its originating spinal nerve and then descends to a prevertebral ganglion, where it synapses with the postsynaptic cell.

11. The mystery of splanchnic nerves

12. White and Gray Rami communicans of Sympathetic system

13. Universal truths regarding sympathetic system outflow White rami communicans only exist to connect T1 to L2 ventral primary rami of typical spinal nerves to the sympathetic chain of ganglia Gray rami communicans exist at All spinal nerve levels. Every ventral primary ramus is connected to the sympathetic chain by a gray ramus Sympathetic chain exists to carry some of the preganglionic fibers from T1 to L2 levels up to the neck head and down into the lower abdomen and pelvis.

14. Afferent autonomic fibers are concerned with the mediation of visceral sensation and regulation of vasomotor and respiratory reflexes. Baroreceptors and chemoreceptors in the carotid sinus and aortic arch involved in the control of heart rate, blood pressure and respiratory activity These afferent fibers are usually carried to the CNS by major autonomic nerves like X CN, Splanchnic/Pelvic nerves Afferent fibers from blood vessels may be carried by somatic nerves.

15. Parasympathetic preganglionic fibers CRANIAL NERVES Oculomotor--- -----III CN Facial---------- -----VII CN Glossopharangeal– IX CN Vagus---------------- X CN PELVIC SPLANCHNIC NERVES S2, S3, S4

16. Ciliary ganglion

17. Sphenopalatine ganglion

18. Otic and submandibular