Anatomy and description of the major contributors to the autonomic nervous system

1. Nervous 3Autonomic Nervous System McKinley and O’Laughlin Chapter 18

2. Introduction What part of the vertebrate nervous system innervates smooth and cardiac muscle and glandular tissues and governs involuntary, vital functions?

3. The ANS affects the following: heart rate digestion respiration rate salivation perspiration diameter of the pupils micturition (urination) sexual arousal

4. Whereas most of its actions are involuntary, some actions of the ANS, such as breathing, work in tandem with the conscious mind.

5. The ANS is: Purely motor (though some references include visceral sensory as an arm of the ANS) A functional, not anatomical, division Opposite is the somatic nervous system Mostly working beyond our conscious awareness

6. Autonomic vs. Somatic If we follow a nerve impulse from the CNS to an effector within the SNS, how many motor neurons would be involved? If we follow a nerve impulse from the CNS to an effector within the ANS, how many motor neurons would be involved?

8. Autonomic vs. Somatic A motor neuron within the ANS that lies between the CNS and a ganglion is what type of neuron? Pre-ganglionic - myelinated A motor neuron within the ANS that lies between a ganglion and an effector is what type of neuron? Ganglionic - unmyelinated

9. Autonomic vs. Somatic What is the axon of a ganglionic neuron with in the ANS? Post-ganglionic axon

10. ANS Divisions What are the 2 divisions of the ANS? Sympathetic division Parasympathetic division

11. ANS Divisions What division of the ANS is primarily concerned with conserving energy and replenishing nutrient stores and has been nicknamed the “rest-and-digest” division? Parasympathetic division

12. ANS Divisions What division of the ANS is primarily concerned with preparing the body for emergencies and is often referred to as the “fight-or-flight” division? Sympathetic division

13. The parasympathetic division is sometimes referred to as “craniosacral” because the nerves arise from the brain stem (mainly vagus) & sacral region The sympathetic division is sometimes referred to as “thoracolumbar” because of the sympathetic neurons in the spinal nerves of these regions.

16. Parasympathetic Division What is another term for the parasympathetic division? _________ division

17. Parasympathetic Division Where are the cell bodies of the preganglionic neurons for the parasympathetic division located? Brainstem S2-S4 (lateral gray matter of spinal cord)

18. Parasympathetic Division Where are the ganglia of the parasympathetic division found? Terminal ganglia - close to target organ Intramural ganglia - within wall of target organ

20. Parasympathetic Division What cranial nerves carry parasympathetic fibers? III Oculomotor VII Facial IX Glossopharyngeal X Vagus

21. Parasympathetic Division The parasympathetic division innervates what structures through the oculomotor nerve? Ciliary muscle Pupillary constrictor of iris Dilator controlled by sympathetic division

22. Parasympathetic Division The parasympathetic division innervates what structures through the facial nerve? Submandibular and sublingual glands Lacrimal gland Glands of nasal cavity, mouth, and palate

23. Parasympathetic Division The parasympathetic division innervates what structures through the glossopharyngeal nerve? Parotid gland

24. Parasympathetic Division The parasympathetic division innervates what structures through the vagus nerve? Thoracic and abdominal organs

26. Parasympathetic Division What specific regions of the spinal cord house the cell bodies of the parasympathetic division of the ANS? Lateral horns

27. Parasympathetic Division What nerves carry fibers of the parasympathetic division of the ANS through the pelvis? Pelvic splanchnic nerves What does ‘splanchnic’ mean? Visceral

29. Parasympathetic Effects Increase saliva production Constrict pupils Constrict airways Produce tears Increase GI motility Contract bladder Erect penis/clitoris

30. Sympathetic Division What is another term for the sympathetic division? _____________ division From what regions of the CNS does the sympathetic division arise? T1-L2 (lateral horns of spinal cord)

31. Sympathetic Division What part of spinal nerves do the preganglionic sympathetic axons travel within as they leave the lateral horn of the spinal cord? Anterior root

32. Sympathetic Division What sympathetic ganglia lie on the left and right sides of the vertebral column from T1-L2? Sympathetic trunk ganglia Paravertebral ganglia What structure of the sympathetic division has the appearance of a pearl necklace? Sympathetic trunk (ganglia and axons)

33. Sympathetic Division What clusters of ganglia of the sympathetic division of the ANS lie within the neck? Cervical ganglia What are the connections between spinal nerves and the sympathetic trunks? Rami communicantes

35. Sympathetic Division What structures carry preganglionic sympathetic axons from the T1-L2 spinal nerves to the sympathetic trunk? White rami What structures carry postganglionic sympathetic axons from the sympathetic trunk to the spinal nerves? Gray rami

38. Sympathetic Division What structures are composed of preganglionic axons that do not synapse in a sympathetic trunk ganglion? Splanchnic nerves Splanchnic nerves of the sympathetic division of the ANS terminate in what structures? Prevertebral (collateral) ganglia

39. Sympathetic Division What structures are singular rather than paired, are anterior to the vertebral column, and are located only in the abdominal cavity? Prevertebral ganglia

40. Sympathetic Division List the 3 prevertebral ganglia Celiac Superior mesenteric Inferior mesenteric

42. Sympathetic Pathways What pathway is a postganglionic axon within if it travels through a gray ramus that is at the same level as the ganglionic neuron to innervate blood vessels or arrector pili muscles or sweat glands? Spinal nerve pathway

43. Sympathetic Pathways What pathway is a postganglionic axon within if the preganglionic neuron synapses with a ganglionic neuron in a sympathetic trunk ganglion, but the postganglionic axon does not leave the trunk via a gray ramus, but instead extends away from the sympathetic trunk ganglion and goes directly to the effector organ? Postganglionic sympathetic nerve pathway

45. Sympathetic Pathways What pathway is a postganglionic axon within if the preganglionic axon passes through the sympathetic trunk ganglia without synapsing and extends to the prevertebral ganglia? Splanchnic nerve pathway

46. Sympathetic Pathways What pathway is a sympathetic axon within if it goes to the adrenal medulla? Adrenal medulla pathway

48. Sympathetic Effects Pupil dilation Airway dilation Sweat production Mass activation response to stress Increased heart rate, blood pressure, breathing rate and depth, dilate pupils, stimulate RAS

49. Autonomic Nervous System Usually both divisions of the ANS innervate organs. Where does this dual innervation not occur? Cutaneous region Includes peripheral blood vessels Sympathetic only

50. Autonomic Plexuses What are collections of sympathetic postganglionic axons, parasympathetic preganglionic axons, and some visceral sensory axons? Autonomic plexuses

51. Autonomic Plexuses List the 5 autonomic plexuses Cardiac plexus Esophageal plexus Pulmonary plexus Abdominal plexus Hypogastric plexus

53. CNS Control of ANS What part of the CNS has the greatest control over the ANS? Hypothalamus What part of the CNS holds nuclei which have a great deal of influence over autonomic function? Brain stem

55. CNS Control of ANS What division of the ANS may process and control certain functions at the level of the spinal cord without involvement of the brain? Parasympathetic E.g. Defecation and urination

57. How does the parasympathetic reflex for urination relate to potty training?

58. The End of Autonomic Nervous System 