1. © 2014 Pearson Education, Inc. PowerPoint ® Lecture Presentations prepared by Leslie Hendon University of Alabama, Birmingham 15 The Autonomic Nervous System

2. © 2014 Pearson Education, Inc. I. The Autonomic Nervous System (ANS) A.The ANS is a system of motor neurons B. The ANS is the general visceral motor division of the PNS C. It innervates: Smooth muscle; Cardiac muscle; Glands D. It regulates visceral functions such as: 1. Heart rate 2. Blood pressure 3. Digestion 4. Urination E. It also contains the general visceral sensory system of the PNS

3. © 2014 Pearson Education, Inc. Peripheral nervous system (PNS) Sensory (afferent) divisionMotor (efferent) division Somatic sensory Visceral sensory Somatic nervous system Autonomic nervous system (ANS) Sympathetic division Parasympathetic division Central nervous system (CNS)

4. © 2014 Pearson Education, Inc. II. Comparison Autonomic and Somatic Motor Systems A. Somatic motor system 1. one motor neuron extends from the CNS to skeletal muscle 2. axons are well myelinated, conduct impulses rapidly B. Autonomic nervous system 1. Chain of two motor neurons to smooth muscle, cardiac muscle, glands a. preganglionic neuron ► ►► postganglionic neuron 2. Conduction is slower than somatic nervous system because a. axons are thinly myelinated (white) or nonmyelinated (grey) b. motor neuron synapses in a ganglion outside the CNS

5. © 2014 Pearson Education, Inc.

6. III. Divisions of the Autonomic Nervous System A. Sympathetic and parasympathetic divisions 1. chains of two motor neurons 2. innervate same structures - cause opposite effects 3. Sympathetic division - during extreme situations a. examples: fear, rage, exercise 4. Parasympathetic division - routine maintenance functions

7. © 2014 Pearson Education, Inc. B. Sympathetic -“fight or flight” 1. activated during EXTREME situations a. examples: exercise, excitement, emergencies 2. sympathetic responses help respond to dangerous situations a. increase heart rate and breathing rate b. increase blood and oxygen to skeletal muscles c. vasoconstriction of other blood vessels d. dilate pupils and bronchioles e. inhibit motility of the digestive tract and urinary tracts

8. © 2014 Pearson Education, Inc. C. Parasympathetic – “rest and digest” (“sit or shit”) 1. Active when the body is at rest 2. Concerned with conserving energy 3. Directs “housekeeping” activities a. digestion b. elimination of feces and urine c. heart rate, b.p., respiration at low-normal levels

9. © 2014 Pearson Education, Inc. Brain stem Cranial Sympathetic ganglia Cervical T1T1 L1L1 Thoracic Lumbar Sacral  stimulatory effect  inhibitory effect  Eye (constricts pupil) Salivary glands Heart Lungs (constricts airways) Stomach Pancreas Gall- bladder Bladder Genitals (erection)                     Genitals (ejaculation) Adrenal gland Gall- bladder Lungs (dilates airways) Salivary glands Eye (dilates pupil) Skin* Heart Stomach Pancreas Liver Bladder SympatheticParasympathetic

10. © 2014 Pearson Education, Inc. A. Emerge from different regions of the CNS 1. sympathetic - also called the thoracolumbar division a. originate from spinal segments (T 1 –L 2 ) 2. parasympathetic - also called the craniosacral division a. originate from III, VII, IX, X and (S 2,3,4 ) B. Length of postganglionic fibers 1. sympathetic - long postganglionic fibers 2. parasympathetic - short postganglionic fibers IV. Anatomical Comparisons

11. © 2014 Pearson Education, Inc. C. Branching of fibers 1. sympathetic fibers a. highly branched; influence many organs at once 2. parasympathetic fibers a. few branches; only localized effect D. Neurotransmitter released by postganglionic axons 1. sympathetic - most release norepinephrine (adrenergic) 2. parasympathetic - release acetylcholine (cholinergic)

12. © 2014 Pearson Education, Inc.

13. V. The Parasympathetic Division A. Cranial outflow 1. originates from the brain (III, VII, IX, X) 2. innervates - organs of the head, neck, thorax, and abdomen B. Sacral outflow 1. originates from spinal segments (S 2,3,4 ) 2. “(S 2,3,4 ) keeps your penis off the floor” 3. innervates - remaining abdominal and pelvic organs

14. © 2014 Pearson Education, Inc. Ciliary ganglion Pterygopalatine ganglion Submandibular ganglion Otic ganglion Cardiac and pulmonary plexuses Lung Heart Parotid gland Submandibular and sublingual glands Nasal mucosa Lacrimal gland Eye CN III CN VII CN IX CN X Preganglionic Postganglionic Cranial nerve CN

15. © 2014 Pearson Education, Inc. Preganglionic Postganglionic Cranial nerve CN Celiac plexus Liver and gallbladder Stomach Pancreas Large intestine Small intestine Rectum Urinary bladder and ureters Genitalia (penis, clitoris, and vagina) Inferior hypogastric plexus Pelvic splanchnic nerves S2S2 S4S4 S3S3

16. © 2014 Pearson Education, Inc. VI. Cranial Outflow (Parasympathetic) A. Preganglionic fibers run via 1. oculomotor nerve (III) 2. facial nerve (VII) 3. glossopharyngeal nerve (IX) 4. vagus nerve (X) B.Cell bodies of preganglionic neurons located in motor cranial nerve nuclei in gray matter of the brain stem

17. © 2014 Pearson Education, Inc. C. Oculomotor Nerve (III) 1. innervate smooth muscles in the eye 2. cause pupil constriction D. Facial Nerve (VII) 1. stimulate secretions of glands in the head 2. examples: lacrimal gland, submandibular salivary glands E. Glossopharyngeal Nerve (IX) 1. stimulate secretion of other salivary glands

18. © 2014 Pearson Education, Inc. F. Vagus Nerve (X) 1. innervate visceral organs of the thorax and most of the abdomen 2. stimulates digestion, lower heart rate, and lower blood pressure 3. sends branches through autonomic nerve plexuses a. cardiac plexus b. pulmonary plexus c. esophageal plexus d. celiac plexus e. superior mesenteric plexus

19. © 2014 Pearson Education, Inc. Superior cervical ganglion Middle cervical ganglion Stellate ganglion Superior mesenteric plexus Celiac plexus Esophageal plexus Pulmonary plexus Cardiac plexus Cardiac branches of the vagus Stomach with vagus nerve Vagus nerve Left vagus nerve

20. © 2014 Pearson Education, Inc. A. Emerges from S 2 to S 4 B. Innervates organs of the pelvis and lower abdomen 1. contraction of urinary bladder for urination 2. erection of the penis - (S 2,3,4 ) 3. inhibits contraction of uterine smooth muscles 4. vasodilation - clitoris and contraction of smooth m. of vagina VI. Sacral Outflow (Parasympathetic)

21. © 2014 Pearson Education, Inc. VI. The Sympathetic Division A. Issues from T 1 to L 2 B. Preganglionic fibers form the lateral gray horn of spinal cord C. Supplies visceral organs in internal body cavities and structures of superficial body regions D. Contains more ganglia than the parasympathetic division E. Located on both sides of the vertebral column F. Linked by short nerves into sympathetic trunks G. Sympathetic trunk ganglia also called: 1. chain ganglia or 2. paravertebral ganglia

22. © 2014 Pearson Education, Inc. VII. Sympathetic Trunk Ganglia A Joined to ventral rami by white and gray rami communicantes (the next picture will show what this actually means) B. Fusion of ganglia  there are fewer ganglia than spinal nerves C. Sympathetic ganglia form a “chain” along the vertebral column 1. most apparent in the cervical region a. superior cervical ganglia b. middle cervical ganglia c. inferior cervical ganglia

23. © 2014 Pearson Education, Inc. Skin (arrector pili muscles and sweat glands) Blood vessels To effector Ventral ramus of spinal nerve Lateral horn (visceral motor zone) Ventral root Gray ramus communicans White ramus communicans Sympathetic trunk ganglion Sympathetic trunk 1. preganglionic nerve cell body in lateral horn of spinal cord 2. axon goes through ventral root of spinal nerve 3. to ventral ramus of spinal nerve 4. through white communicans (myelinated) 5. synapses on postganglionic nerve cell body in sympathetic ganglion 6. postganglionic axon through grey communicans (unmyelinated!!!) 7. to effector organ

24. © 2014 Pearson Education, Inc. Skin (arrector pili muscles and sweat glands) Blood vessels To effector Ventral ramus of spinal nerve Lateral horn (visceral motor zone) Ventral root Gray ramus communicans White ramus communicans Sympathetic trunk ganglion Sympathetic trunk 1. Synapses with a postganglionic neuron at the same level and exit on a spinal nerve at that same level or

25. © 2014 Pearson Education, Inc. 1 1. Preganglionic nerve in lateral horn Skin (arrector pili muscles and sweat glands) Blood vessels To effector 2 2. Ventral root of spinal nerve 3 3. White ramus communicans 4 4. Sympathetic chain ganglion 6 5. Grey ramus communicans 5 6. Postganglionic nerve axon 2. Synapses with a postganglionic neuron at a different level and exits on a spinal nerve at that same level

26. © 2014 Pearson Education, Inc. Ventral root Sympathetic trunk ganglion Sympathetic trunk Gray ramus communicans White ramus communicans Location of the sympathetic trunkDissection of posterior thoracic wall, right side Ventral ramus of spinal nerve

27. © 2014 Pearson Education, Inc. D. Pathways to Body Periphery 1. innervate sweat glands, arrector pili muscles, blood vessels E. Pathways to the Head 1. originate from T 1 –T 4 2. synapse in superior cervical ganglion 3. innervate glands, smooth muscles, blood vessels of head F. Pathways to Thoracic Organs 1. originate from T 1 –T 6 2. run directly to the effector organ

28. © 2014 Pearson Education, Inc. G. Pathways to Thoracic Organs 1. originate from T 1 –T 6 2. run directly to the effector organ 3. functions in this region are to: a. increase heart rate b. dilate the bronchioles c. dilate arteries of the heart d. inhibit muscles and glands of the digestive system H. Pathways to Pelvic Organs 1. originate from T 5 –L 2 2. inhibit activity of smooth m. and glands in the visceral organs

29. © 2014 Pearson Education, Inc. Pons T1T1 L2L2 Sympathetic trunk (chain) ganglia Superior cervical ganglion Middle cervical ganglion Inferior cervical ganglion Celiac ganglion Superior mesenteric ganglion Inferior mesenteric ganglion Preganglionic Postganglionic Genitalia (uterus, vagina, and penis) and urinary bladder Rectum Large intestine Small intestine Kidney Adrenal medulla Spleen Stomach Liver and gallbladder Lung Heart Salivary glands Blood vessels; skin (arrector pili muscles and sweat glands) Nasal mucosa Lacrimal gland Eye

30. © 2014 Pearson Education, Inc. VIII. The Role of the Adrenal Medulla A. Major organ of the sympathetic nervous system B. Constitutes largest sympathetic ganglia C. Secretes large amounts of norepinephrine and epinephrine D. Stimulated to secrete by preganglionic sympathetic fibers Remember: “Fight or Flight” Example: bear running out of the woods to eat your child!!!!

31. © 2014 Pearson Education, Inc. Sympathetic trunk Ventral root Thoracic splanchnic nerves Kidney Adrenal gland Epinephrine and norepinephrine Capillary Adrenal medulla cells Adrenal medulla Spinal cord: T 8 –L 1

32. © 2014 Pearson Education, Inc.

35. IX. Visceral Sensory Neurons A. General visceral sensory neurons monitor these sensations 1. stretch 2. temperature 3. chemical changes 4. irritation B. Nerve cell bodies are located in the dorsal root ganglion

36. © 2014 Pearson Education, Inc. C. Visceral pain 1. no pain results when visceral organs are cut 2. visceral pain results from chemical irritation or inflammation 3. visceral pain often perceived to be of somatic origin ► phenomenon of referred pain

37. © 2014 Pearson Education, Inc. A map of referred pain Lungs and diaphragm Gallbladder Appendix Heart Liver Stomach Pancreas Small intestine Ovaries Colon Kidneys Urinary bladder Ureters

38. © 2014 Pearson Education, Inc. X. Visceral Reflexes A. Visceral sensory/autonomic neurons role in visceral reflex arcs: 1. defecation reflex 2. micturition reflex (urination impulse) B. NOTE: you do not “think” these reflexes; like patellar tendon reflex C. Some visceral reflexes are simple spinal reflexes D. Others do not involve the CNS - strictly peripheral reflexes

39. © 2014 Pearson Education, Inc. A visceral reflex Stimulus Dorsal root ganglion Spinal cord Autonomic ganglion Response 12345 Visceral effector Efferent pathway (two-neuron chain) Preganglionic neuron Postganglionic neuron Integration center May be preganglionic neuron (as shown) May be a dorsal horn interneuron May be within walls of gastrointestinal tract Visceral sensory neuron Sensory receptor in viscera

40. © 2014 Pearson Education, Inc. 54321 The baroreceptor reflex Increased blood pressure 12345 Blood pressure decreases Parasympathetic stimulation of heart decreases heart rate. Efferent pathway via the vagus nerves (CN X) Integration occurs in cardiac center of medulla oblongata. Sensory impulses are carried on visceral sensory fibers in the glosso- pharyngeal nerves (CN IX). Baroreceptors in carotid sinus are simulated.

41. © 2014 Pearson Education, Inc. XI. CNS Control of the ANS A. The ANS is not under direct voluntary control B. Some parts of the CNS help coordinate the ANS 1. brain stem 2. spinal cord 3. hypothalamus 4. amygdala 5. cerebral cortex

42. © 2014 Pearson Education, Inc. C. Hypothalamus—the main integration center of the ANS A. medial and anterior parts ► direct parasympathetic functions B. lateral and posterior parts ► direct sympathetic functions D. People can exert some control over autonomic functions 1. feelings of calm during meditation a. influence of cerebral cortex on parasympathetic centers in hypothalamus 2. voluntary sympathetic response a. recalling scary event

43. © 2014 Pearson Education, Inc. Communication at subconscious level Cerebral cortex (frontal lobe) Limbic system (emotional input) Hypothalamus The “boss”: Overall integration of ANS Brain stem (reticular formation, etc.) Regulates pupil size, heart, blood pressure, airflow, salivation, etc. Spinal cord Reflexes for urination, defecation, erection, and ejaculation

44. © 2014 Pearson Education, Inc. XII. Disorders of the ANS A. Raynauds disease - characterized by constriction of blood vessels 1. provoked by exposure to cold or by emotional stress B. Achalasia of the cardia 1. defect in the autonomic innervation of the esophagus C. Congenital megacolon (Hirschsprung’s disease) 1. birth defect 2. parasympathetic innervation of distal large intestine fails to develop correctly 3. feces and gas accumulate proximal to defect

45. © 2014 Pearson Education, Inc. D. Achalasia of the cardia 1. defect in the autonomic innervation of the esophagus E. Congenital megacolon (Hirschsprung’s disease) 1. birth defect 2. parasympathetics of distal large intestine fails to develop correctly 3. feces and gas accumulate proximal to defect