The Autonomic Nervous System PDF

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> enteric nervous system collateral ganglia- ↓ abdominal organs COLLATERAL GANGLIA Help regulate activities of abdominal organs AUTONOMIC NERVOUS SYSTEM - Considered part of enteric nervous system Receive input from splanchnic nerves and central sympathetic neurons splanchnic newvses splanchnic nerves splanchnic nerves OVERVIEW OF THE AUTONOMIC NERVOUS SYSTEM central sympathetic neurons central sympathetic neurons central sympathetic SOMATIC NERVOUS SYSTEM VS AUTONOMIC NERVOUS SYSTEM neurons somatic-voluntary ANATOMY OF A SYMPATHETIC NERVOUS SYSTEM PATHWAY Somatic Nervous System skeletal muscle Cell body of the preganglionic neuron is in lateral horn of - Causes contraction of skeletal muscle autonomic involuntary the thoracic or lumbar region of the spinal cord - thoracolumbar Controls voluntary responses cardiac and smooth Preganglionic axon synapses with postganglionic neuron close Autonomic Nervous System to spinal cord Controls cardiac and smooth muscle and glands Usually within sympathetic chain ganglia Controls involuntary responses Long postganglionic axon synapses within target organ Helps maintain homeostasis in the body CHARACTERISTICS OF THE AUTONOMIC NERVOUS SYSTEM innervates internal organs - sympathetic fighty Might Primarily innervates internal organs parasympathetic rest and digest- > with - Two divisions: apply nerves 1. Sympathetic Nervous System Associated with “fight-or-flight” responses 2. Parasympathetic Nervous System Associated with “rest and digest” responses restand digest Most organs receive dual innervation from both divisions blood vessels sweet glands , DIVISIONS OF THE NERVOUS SYSTEM arrector pili muscles The autonomic nervous system is divided into sympathetic and parasympathetic divisions NEUROTRANSMITTERS OF THE SYMPATHETIC NERVOUS SYSTEM 6 Acetylcholine (ACh) pre-and post-ganglionic neurons Used at the synapse of the sympathetic preganglionic and postganglionic neurons Norepinephrine Released by postganglionic neurons onto target cells fight or flight SYMPATHETIC DIVISION OF THE AUTONOMIC NERVOUS SYSTEM Responds to a threat to our homeostasis (stress) or enables fight/flight survival sympathetic nervous system Increases oxygen delivered to skeletal muscle DigestiveYang - Increases -sweating ward skeletal Blood is shifted away from the digestive system and toward skeletal muscle - Pupils dilate I11 Brain becomes alert SYMPATHETIC PATHWAYS Preganglionic cell bodies in thoracic and lumbar regions of spinal cord - thoracic and - Referred to as thoracolumbar system SYMPATHETIC NERVOUS SYSTEM ACTIVATION OF HORMONE RELEASE lumbar - Synapse with postganglionic neuron Activation of the sympathetic NS can cause - hormone release cell bodies in sympathetic chain in the- adrenal medulla Short Epinephrine (adrenaline) and norepinephrine ganglia white rami communi- 23 ganglia located next to (noradrenaline) cantes vertebral column Preganglionic axons terminate in adrenal medulla Long Some preganglionic neurons synapse No ganglion involved gray rami communicantes outside of sympathetic chain Postganglionic neurons release hormones directly into blood Short preganglionic axons- project through white rami communicantes contains PARASYMPATHETIC DIVISION OF THE AUTONOMIC NERVOUS SYSTEM and can synapse: white rami communicates Active when body is not stressed or under a threat At the ganglion at the same Controls “rest and digest” activities & the ganglion the level parasymphatetic at same level salivation Salivation Salivation at a more superior or inferior Lacrimation brainstem & sacral Sp. At a more superior or inferior lacrimation lacrimation ganglion ganglion Urination Urination = craniosacral system defectioane collateral ganglia at prevertebral ganglia or At prevertebral ganglia or Digestion digestion adrenal medulla Defecation defecation symphatetic the adrenal medulla sexual arousal Sexual arousal thoracic a lumbar v. Long postganglionic axons project to target effector through gray rami thoracolumbar communicantes PARASYMPATHETIC PATHWAYS system prevertebral ganglia celiac ganglion Cell bodies of preganglionic neurons located in brain stem and COLLATERAL GANGLIA superior/ inferior mesenteric ganglion sacral spinal cord Includes the celiac ganglion, superior mesenteric ganglion, and Referred to as craniosacral system I inferior mesenteric ganglion Long preganglionic axons project to effector through cranial Located anterior to vertebral column nerves and spinal nerves Also known as prevertebral ganglia prevertebral ganglia Synapse with postganglionic cell bodies near or in effector W - collateral ganglion prevertebral collateralgia id  symphatetic parasymphatetic thoracolumbar brain stem and pathways sacral cell bodies system anatomy of pathways acetylcholine (ACK) acetylcholine neurotransmitters - prea post norepinephrine post - Me celdies fight or flight Sapphire ↑ restand Preganglionic CB digest PRE-Preganglionic Axon CN10 (ragus) sport - gray rami communicates Ach Neurotransmitters Ach-prepost NE-post norepinephrine  in (vagus newves innervates CNI11 Coculomotor nerve) organs - iris CNX - - TAP (thoracic, abdominal, CN VII (facial nerve)-terygopalatine sacral reginat pelvic carities form pelvic carity CN (X (glossopharyngeal nerve) struction - - Vagus nerve Located in terminal or intramural ganglia innervates organs in NEUROTRANSMITTERS OF THE PARASYMPATHETIC NERVOUS SYSTEM Short postganglionic axons project to target organ thoracic abdominal , , Acetylcholine (ACh) Major parasympathetic ganglia and pathways: pelvic cavities Released by preganglionic and postganglionic Preganglionic axons in oculomotor nerve (CN III) neurons of parasympathetic nervous system project to ciliary ganglion; postganglionic neurons parasympathetic then control iris Preganglionic axons in facial nerve (CN VII) project pathways & to pterygopalatine and submandibular ganglia to CN VII - SNT ganglig control production of saliva, mucus, and tears Innervates two of the three salivary gland pairs Preganglionic axons of glossopharyngeal nerve (CN CHEMICAL COMPONENTS OF THE AUTONOMIC RESPONSES IX) project to otic nucleus to control saliva SYNAPSES OF THE AUTONOMIC NERVOUS SYSTEM production Cholinergic synapses cholinergis Innervates only one pair of salivary glands a nicotini ni c Acetylcholine (ACh) is neurotransmitter released Major parasympathetic ganglia and pathways: Adrenergic synapses adrenergic Preganglionic axons project through vagus nerves Norepinephrine is neurotransmitter released (CN X) to innervate organs in thoracic, abdominal, and pelvic cavities TAP TYPES OF CHOLINERGIC RECEPTORS Preganglionic axons mix with sympathetic Nicotinic receptors endogenous ligand postganglionic axons in plexuses Endogenous ligand—acetylcholine I same Preganglionic axons from sacral region form pelvic nicotine Exogenous ligand—nicotine splanchnic nerves chemically-gated ion channel genous ligand Chemically-gated ion channel Travel through hypogastric plexus and Muscarinic receptors (Ach) synapse in terminal or intramural ganglia Endogenous ligand—acetylcholine Postganglionic axons project into pelvic muscarine Exogenous ligand—muscarine cavity Trigger changes in cell without allowing ions to pass through membrane endogenous ligand exo-nicotine chemically-gated - ion channel endo : ACh exo : muscarine VARICOSITIES VARICOSIMES Postganglionic synapses in the autonomic nervous system differ from the neuromuscular junction (NMJ) Synapses occur as swellings along synapses occur as the length of postganglionic axons swellings sa length - Called varicosities ng postganglionic axons synapses > swellings - ADRENERGIC RECEPTORSI I ne Adrenergic receptors bind to post- norepinephrine norepinephrine - and epinephrine - avons Alpha(α)-adrenergic receptors α1—located in skin, GI SkIn G1 pelvIc, 131-contraction , , and pelvic organs, and blood vessels moothsee X1 Cause contraction of smooth muscle 4. ,a x2 α2—found in pancreas, platelets, brain, and spinal cord parad Cpcs of pancake Inhibit insulin release platesbutter hibit in Syrup spinal cord E Promote blood clotting Blood clowing Beta(β)-adrenergic receptors β1—found in heart and kidney Increase heart rate, force of contraction, B1 G and secretion of renin Blood vessels 21 vS β2—found in blood 41 vessels, lungs, uterus, stomach, uHMB B2 and small intestines BV lungs 2 terus , semain su , , small intestine , IUNGS !! Cause relaxation of smooth muscle B3 β3—found in adipose tissue ADIPOS3 TISU3-breakdown of Stimulate breakdown of lipids lipids ANATOMY OF A PARASYMPATHETIC NERVOUS SYSTEM PATHWAY Cell bodies of preganglionic neurons located in brainstem and sacral spinal cord Long preganglionic axons project to ganglia near or within target organ Short postganglionic axons synapse with cells in target organ adregernic receptors bind to norepinephrine and epinephrine alpha &adregemic receptors &I - blood vessels , skin , GI , pelvic organs -contractions of smooth muscle & 2- pancreas, platelets, brain , spinal cord - inhibit insulin release - promote blood clotting betas adregernic receptors B1-heart and Kidneys -increase heart rate , force of contraction secretion of renin B2-blood vessels , lungs , uterus, stomach, small intestine - relaxation of smooth muscle +issu3 83-adipos3 - stimulate breakdown of lipids  nicotinic endogenous ligand endo : Ach exo : nicotine channels chemically-gated ion muscarinic ACh THE CHOLINERGIC AND ADRENERGIC SYNAPSES OF THE ANS endo : choli Acetylcholine is used at cholinergic synapses exo : muscarine Receptors are either nicotinic or muscarinic adve Norepinephrine is used at adrenergic synapses Alpha-1, alpha-2, beta-1, beta-2, and beta-3 receptors AUTONOMIC RECEPTORS Receptors of the autonomic nervous system BROAD IMPACTS OF AUTONOMIC RESPONSES MAINTAINING HOMEOSTASIS Both divisions of the autonomic nervous system innervate most organs dual innervation Called dual innervation blood vessels ONLY SYMPA sweat glands Blood vessels, sweat glands, and arrector arrector pili muscles pili muscles receive only sympathetic innervation The divisions usually have opposite effects on an AUTONOMIC REFLEXES AND HOMEOSTASIS organ AUTONOMIC REFLEXES Parasympathetic dominance—effects of parasympathetic Help maintain internal homeostasis nervous system are seen Important in maintaining parameters like: rest digest Lower heart rate, increased GI activity, pupil dilation, Blood pressure airway constriction, decrease breathing rate Heart rate Sympathetic dominance—effects of sympathetic nervous Airway diameter system are seen Digestive activity Opposite of parasympathetic effects Components of autonomic reflex arcs are similar to those in fighlight somatic reflex arcs AUTONOMIC TONE autonomic tune Effectors are smooth in cardiac muscle and glands Balance between parasympathetic and sympathetic afferent one neuron afferent dominance when an organ is at rest THE STRUCTURE OF REFLEXES - branch efferent two neurons Different for each organ parasympathetic Afferent branch is a single neuron - somatic Parasympathetic tone dominates the heart at rest - - single Sensory info comes from somatic and special senses viscera sa heart Lowers heart rate to normal range - neuron and viscera sympathetic special senses Sympathetic tone dominates blood vessels at rest · Some visceral sensations are not consciously blood Adjusts constriction of vessels to maintain blood perceived vessels pressure Efferent branch is two neurons - Two Preganglionic neuron synapses with postganglionic STRESS neurons neuron in a ganglion Autonomic nervous system helps body respond to stress Postganglionic neuron projects to target tissue Aim is to increase nutrients in blood and deliver more blood to head and muscles Stress response results in: 1. Lipid breakdown and increased blood glucose 2. Airway dilation for increased oxygen in blood 3. Increased blood flow to skeletal muscles; decreased blood flow to viscera 4. Higher blood pressure to increase speed of delivery to brain and muscles cardiac contraction Endocrine hormones also help - regulates heart rate & strength ng Prolonged stress has negative effects on the body pulmonary - regulates size ng airway sa lungs 1. Chronic high blood pressure and diabetes esophageal-controls movement ng food sa esophagus Exercise also initiates stress response abdominal aortic abdominal organes 1. Changes are considered beneficial - autonomic plexuses AUTONOMIC PLEXUSES 2. Parasympathetic dominance after exercise can Combinations of sympathetic and parasympathetic axons reverse some effects of chronic stress rate and Cardiac plexus – -regulates heart rate and strength of heart of contraction sym + para axons strength ___________________________________end_________________________________ contractility = autonomic plexuses Pulmonary plexus – regulates size of airways in lungs 4 size of airways in lungs Esophageal plexus – = regulates movement of food movement of NOTES:food through esophagy through esophagus Abdominal aortic plexus – regulates abdominal - abdominal organsa pelvic tissues Cardida organs and pelvic tissues - CPEA pulmonary - Celiac, superior mesenteric, inferior esophageal mesenteric, and hypogastric plexuses abdomina aortic celiac , superior a inferior mesenteric Collateral ganglia hypogastric plexuses prevertebral ganglid