Controlling Organ Functions with Autonomic Nervous System

1. How do we control baseline organ functions and metabolic activities with the autonomic nervous system? 11/29 12/1 • What does the Autonomic Nervous System (ANS) do? • How do nerve pathways of Somatic NS and ANS differ? • How does the SNS mediate a fight-or-flight response? • How does the SNS create extremely diffuse responses? • Is SNS effect strictly synaptic or blood-stream mediated? • What does the PNS do with respect to S.L.U.D.? • Why is PNS activity more resistant to spinal cord damage? • What are the neurotransmitters and receptors that mediate the SNS and PNS responses? • Why does nicotine stimulate both SNS and PNS activity? • Can the cortex influence the autonomic nervous system?

2. 10 point Review Assignment Final Exam SummaryDue in class Friday Dec 2nd • The comprehensive final is based on the materials in the three prior lecture units. • Lab materials will not be on the lecture final unless the information was also presented in lecture. • Review your notes to prepare for the final exam, the comprehensive exam is based on what is in the notes, not the practice exam. • For each unit (see syllabus) provide a sheet of paper (sheets) with 50 specific things (#1-#50 items/unit X 3 units = 150 items) thatyou learned in Anatomy and Physiology 211. Be sure each item consists of a sentence with at least 10 words. Copy before handing it in if you want to use it as a review study guide. MUST BE HAND WRITTEN! • STAPLE the sheets together when you hand it in (no paperclips, dog-ears, bubble gum).

3. The autonomic nervous system A.N.S. uses visceral reflexes to control and modify organ function in an involuntary fashion. The ANS works without consciously thinking about it. • ANS is critical for maintaining homeostasis! • Clinically the ANS is the target of many drugs! Two Divisions of ANS: Sympathetic NS: NT= ACH, Epi and NE MANAGES STRESSFUL CONDITIONS! Distribution at synapses Distribution into blood Prepare body for stress!! Parasympathetic NS: NT= ACH MANAGES RELAXED STATE! Distribution ONLY at a synapse Prepare organs for relaxation!! This is your friend after a turkey dinner!

4. Autonomic nervous system uses reflex-like visceral responses to help maintain homeostasis. A characteristic structure of the ANS are ganglia (clusters of nerve cell soma outside CNS). How do normal persons prevent high blood pressure with the PNS?

5. Somatic and Autonomic nervous systems use VERY different pathways! In ANS unmyelinated terminal neurons (post-ganglionic) create a diffuse response where many organs are effected at the same time. Autonomic “Tone” refers to how much SNS/PNS activity is occurring at a given time. ACH=NT at preganglionic synapse for both SNS and PNS At postganglionic synapse: SNS=NE or EPI PNS=ACH

6. PNS=ACH preganglionic, ACH postganglionic (target organ cell) SNS= ACH preganglionic, NE/EPI postganglionic (sometimesACH) EPI/NE are degraded much more slowly than ACH……longer effect Drugs that mimic EPI/NE to stimulate parts of SNS

7. Parasympathetic Ganglia generally at the target organ!Sympathetic Ganglia generally are more distant from the final target organ sitting in the “Sympathetic Chain Ganglions”Also: Celiac, Superior/Inferior Mesenteric Ganglia, splanchnic nerve and collateral gangliaACH is the neurotransmitter in SNS and PNS ganglia!

8. SNS, PNS and Somatic Nerves Exit the CNS at different locations!Why is this important following a spinal cord injury?

9. What organs are targeted by the PNS? What happens to organs during relaxation? What is S.L.U.D.? What are implications of SLUD when acetycholinesterase inhibitors or nicotine are present?

10. The PNS stimulates body activities that occur while at rest by releasing ACH at target synapses. • The ganglia are near the target, not in a chain. • PNS nerves exit at top or bottom of CNS. • You eat/digest when you are relaxed! Usually… Cranial PNS Exit Points: III, VII, IX: lacrimal g., pupillary m., salivary g. X=Vagus n.>jugular foramen>hypogastic plexus Vagus Nerve X=Innervates thoracic and abdominal organs!! Pelvic PNS Exit Points: S2-S4:  Rectum, Bladder and Genitals • Why is control of abdominal organs partially maintained after a spinal cord is severed?

11. How are nervous responses in the SNS and PNS mediated through slightly different transmitters, receptors and receptor localizations in different locations? PNS has one transmitter: acetylcholine What are the 2 main receptor classes? Nicotinic Muscarinic SNS has 2 main catecholamines: Epi and NE • What are the 5 main Epi/NE receptor classes? Where are they found? • Know these below! • Alpha1 • Alpha2 • Beta1 • Beta2 • Beta3 Preganglionic SNS synapse requires ACH and nicotinic receptor!

12. What organs are targeted by the SNS? What happens to our organs during the fight-or-flight response and nervousness about exams?How does the SNS reach postganglionic synapses in the pupil?

13. The adrenal glands are very special SNS structures because their post-ganglionic endings release EPI and NE directly into the blood stream, but not into a synapse! • Location of normal SNS ganglion/chain ganglia/synaptic release is STILL the norm in SNS: • Location of adrenal glands: • Location of adrenal ganglion: • Two Parts of Adrenal Gland: A. Cortex- A. Medulla- • Adrenal Medulla releases catecholamines: 85% adrenalin (EPI) 15% noradrenalin (NE) Remember that catecholamines are destroyed more slowly than ACH so their effects last much longer. In the movie Pulp Fiction, why was an intracoronary EPI injection made when the woman’s heart stopped?

15. Effects of Smoking: Nicotine in tobacco stimulates any nicotinic receptor for acetylcholine regardless of location. What would happen in the following organs if you smoked a nicotine-rich cigarette? Preganglionic cells release ACH that binds a NIC receptor on the postganglionic cell for both the PNS and SNS. • General PNS Output (SLUD)- • General SNS Output- • Gut: • Heart: • Saliva: • Muscle contractions (smooth and skeletal): • Blood pressure:

16. Central Control of Autonomic Functions: • Cerebral Cortex does not have voluntary control of the ANS, although the cortex can “influence” ANS function. • Cortex influences the ANS by modifying the function of special nuclei in the hypothalamus. • The hypothalamus modifies the function of nuclei in the brainstem. • Nuclei in the brainstem determine when most ANS output is sent out of the brain in tracts within the spinal cord or as cranial nerves. ALSO: Many autonomic reflexes need only access a section of spinal cord and work independently of the brain! (urination and defecation)

17. The ANS and Neuropharmacology: There are a tremendous number of drugs that mimic or block ANS neurotransmitters from reaching their receptors. Sympathomimetic Drugs: Phenylephrinealpha-1 receptor and helps a runny nose Albuterolbeta-2 receptor to open airways and helps asthma Sympathetic NS Blocking Drugs: Propranolol- blocks beta-1 receptors in heart from being activated Yohimbine- blocks alpha-2 receptors from creating IPSPs Parasympathomimetic Drugs: Nicotinenicotinic receptor and wide ranging effects Muscarinemuscarinic receptorpupil constricts Atropineblocks muscarinic receptor in eye during eye exam

18. Final Exam:75 points- You Need Two Scantrons • Scantron #1: Name and Form Letter • 25 points: Unit Test: All of CH 15 and 16 as covered in lecture. • About 22 pts multiple choice+ 3pt written + 2 pt X-credit Q • Scantron #2: Name and Form Letter • 50 points: Comprehensive over all notes chapters covered in AP 211. • About 16 pts per unit + 3 pt written + 2 pt X-credit Q