1. 1 Autonomic Nervous System

2. 2 Lecture Overview Review/Questions from last lecture (Brain II/Cranial Nerves) Autonomic Nervous System, ANS (pp. 87-89) –Overview –Divisions –Structure –Neurotransmitters –Actions

3. 3 Review from Last Lecture (Brain II/CN) Brain II (pp. 84-87) –Cerebrum Myelinated tracts Basal ganglia Sensory areas Motor areas –Brain coverings (meninges) –Cerebrospinal fluid (CSF) –Ventricular System –Cranial nerves

4. 4 Autonomic (Visceral) Nervous System CNSPNS

5. 5 Autonomic Nervous System functions without conscious effort controls visceral (squishy!) activities regulates smooth muscle, cardiac muscle, and glands Two Main Divisions sympathetic – prepares body for fight or flight situations parasympathetic – prepares body for rest and digest activities Third Division – Enteric Nervous System (ENS) for alimentary canal

6. 6 Somatic vs. Autonomic Nervous Systems Figure from: Marieb, Human Anatomy & Physiology, Pearson, 2013 Dual

7. 7 Autonomic Nerve Fibers *ANS = a motor division of the PNS

8. 8 Sympathetic Division of ANS Figure from: Saladin, Anatomy & Physiology, McGraw Hill, 2007 Effectors in muscles and body wall Effectors in head and thoracic cavity * * * (T5 – T12) Paravertebral ganglion

9. 9 Autonomic Plexuses Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004 Sympathetic collateral (prevertebral) ganglia Autonomic plexuses receive sympathetic and parasympathetic, postganglionic fibers

10. 10 Spinal Nerves – Autonomic Fibers Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004 Sympathetic ganglion - cell bodies of postganglionic sympathetic neurons * * * * Three fates of a preganglionic sympathetic axon: 1) synapse in same chain ganglion 2) Ascend/descend to synapse in another chain ganglion 3) Pass through without synapsing (form prevertebral, or collateral ganglia)

11. 11 Were you paying attention? 1 2 8 7 6 5 3 4 9 10 11 12

12. Autonomic Neurotransmitters = always excitatory in ganglia

13. 13 Actions of Autonomic Neurotransmitters depend on receptor Cholinergic receptors bind acetylcholine nicotinic excitatory muscarinic excitatory or inhibitory Adrenergic receptors bind norepinephrine alpha (Types 1 and 2) different responses on various effectors beta (Types 1 and 2) different responses on various effectors

14. 14 Sympathetic Myoneural Junctions Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004 NE is either: - reabsorbed and reused or broken down by monoamine oxidase (MAO) in varicosities - or broken down by catechol-O- methyltransferase (COMT) in surrounding tissues

15. 15 Actions of Cholinergic Receptors Always excitatory Cholinergic receptors Nicotinic receptors  always excitatory Muscarinic  Excitatory or inhibitory Remember: the RECEPTOR determines the effect of a neurotransmitter (Sweat glands, blood vessels to skeletal muscles, brain)

16. 16 Sympathetic Division - Divergence NOTE: Arrangement of nerves creates DIVERGENCE Sympathy spreads…

17. 17 Sympathetic Division of the ANS SYMPATHETIC (Thoracolumbar outflow) Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 Fight or Flight “E” situations Emergency Embarrassment Excitement Exercise

18. 18 Parasympathetic (Craniosacral outflow) Salivation Lacrimation Urination Digestion Defecation 3 decreases - Heart rate - Airway diameter - Pupil size (constrict) “REST AND DIGEST” Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004

19. 19 Control of Autonomic Activity Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 Sympathetic Parasympathetic Sympathetic and Parasympathetic

20. 20 Review of Autonomic Nervous System Branch of ANSPARASYMPATHETICSYMPATHETIC General Function * “rest and digest” * (SLUDD); Salivation, lacrimation, urination, digestion, defecation * 3 decreases; ↓ heart rate, ↓ pupil size, ↓ airway diameter * “fight or flight” * E situations: Emergency, exercise, embarrassment, excitement Origin of Preganglionic fiber cranial region of brain or sacral region of spinal cord (craniosacral outflow) thoracic or lumbar region of spinal cord (thoracolumbar outflow) Divergence for widespread activation of body Location of Ganglia within or near effector organalongside or in front of spinal cord (paravertebral ganglia; collateral ganglia) NTx secreted by postganglionic fiber acetylcholineNorepinephrine (some acetylcholine; sweat glands, smooth muscle on blood vessels, brain)