Autonomic Nervous System I_ Overview and Sympathetic PDF

Autonomic Nervous System I: Introduction Course Learning Objective Nervous: Describe how the body communicates with itself by identifying anatomical structures and tracing pathways of the nervous system in order to aid in medical diagnoses when these systems a...

Autonomic Nervous System I: Introduction Course Learning Objective Nervous: Describe how the body communicates with itself by identifying anatomical structures and tracing pathways of the nervous system in order to aid in medical diagnoses when these systems are compromised.  Lecture Learning Objectives 1. Describe the role of the 3. Describe the differences between autonomic nervous system; the sympathetic and parasympathetic nervous systems. compare its similarities and Focus on differences to the peripheral a. Response nervous system b. Effect on structures/systems c. CNS contributions 2. Map or diagram how the ANS d. Location/name of ganglia involved communicates; include the spinal cord, preganglionic 4. Diagram preganglionic and neurons, postganglionic postganglionic fibers of the neurons, and the effector sympathetic and parasympathetic nervous systems to compare and organ contrast their anatomical differences and length of fibers Autonomic Nervous System (ANS)  LO 1 ANS- What does it do? Involuntary Control/monitor body’s internal environment Primarily works through motor innervation Motor (efferent) smooth (involuntary) muscle modified cardiac muscle glandular cells Sensory (afferent) Travel alongside motor Play a role in autonomic reflexes, conducting visceral pain, and regulatory function Clinically Oriented Anatomy, Moore et al., 2018  LO 2 How does it communicate? Pathways always involves a series of two neurons Preganglionic (presynaptic) and postganglionic (postsynaptic) Multipolar = motor; unipolar= sensory Preganglionic Postganglionic  LO 2 How does it communicate? Pathways always involves a series of two neurons Preganglionic (presynaptic) and postganglionic (postsynaptic) Multipolar = motor; unipolar= sensory For motor innervation Preganglionic neurons = lower motor neurons (LMN) A. Begin in neurons in CNS gray matter B. Exit CNS via anterior roots C. Synapse in autonomic ganglia Postganglionic neurons = A. Join spinal/cranial nerves or form splanchnic nerves B. Travel to internal organs or skin CNS Preganglionic Postganglionic  LO 3a Sympathetic vs. Parasympathetic Visceral efferent nerve fibers and their ganglia are organized into Sympathetic Activated in emergency situations Catabolic, “Flight-or-fight” response Regulate vessels through vasomotion Parasympathetic Brings body to homeostasis Anabolic, “Rest and digest”  LO 3bc Organ Sympathetic Parasympathetic Related Structures Eyes (pupil) Skin None Lacrimal and salivary glands Heart Blood vessels None Lungs  LO 3bc Organ Sympathetic Parasympathetic Digestive system Liver and gallbladder (as related to glucose/glycogen) Urinary system Genital system Suprarenal gland (secretes None adrenaline)  LO 3c Anatomical Distinction- CNS Contributions Sympathetic (thoracolumbar) Only enter sympathetic trunk via spinal nerves T1- L2 Will then travel in sympathetic trunk to level of: A. Dermatome level for skin innervation- synapse and travel with spinal nerves B. Cranial glands or thoracic organs- synapse in sympathetic paravertebral ganglia then exit sympathetic trunk via splanchnic nerves C. Abdominal organs- leave sympathetic trunk, synapse in prevertebral ganglia, travel to organs  LO 3c Anatomical Distinction- CNS Contributions Parasympathetic (craniosacral) Leave CNS via cranial nerves (CN) III (3), VII (7), IX (9), and X (10) Will synapse in autonomic ganglia in the crania Sacral spinal nerves S2- S4 Will synapse in intramural ganglia next to or within organs  LO 3d Anatomical Distinction- Location of Sympathetic Ganglia Sympathetic trunk- paired vertically oriented Prevertebral ganglia- Non-paired sympathetic ganglia structures located lateral to vertebral column in located only in the abdominal cavity adjacent to major neck, thoracic and abdominal cavities. arterial branches of aorta. Help form autonomic nerve Comprised of paravertebral ganglia and plexuses. associated nerve fibers Posterior wall of thoracic cavity Posterior wall of abdominal and pelvic cavity Abdominal and pelvic cavity  LO 3d Anatomical Distinction- Pterygopalatine Ciliary Location of Ganglia Otic Parasympathetic (craniosacral) Cranial ganglia 1. Ciliary 2. Otic 3. Submandibular 4. Pterygopalatine Intermural (within) or terminal (near) ganglia in or near organs Submandibular Internal view of left crania  LO 4 Sympathetic and Parasympathetic Fibers  ANS II- Sympathetic Nervous System Course Learning Objective Nervous: Describe how the body communicates with itself by identifying anatomical structures and tracing pathways of the nervous system in order to aid in medical diagnoses when these systems are compromised.  Lecture Learning 5. Trace/diagram/draw-out the visceral sympathetic Objectives pathways for the head, neck, and thoracic organs from the lateral horn to associated splanchnic nerves. 1. Visually identify sympathetic and associated Include: structures on ID manual 1. Contributing spinal levels 2. Nah... 2. Path within the sympathetic trunk 3. Location of, and transition between, preganglionic and postganglionic neurons (location of synapse) 3. Review the structures associated with the SNS, recalling their role in the response 4. Type of effect on associated organs 4. Trace/diagram/draw-out the 3 parietal 6. Trace the pathways for the sympathetic innervation to sympathetic pathways from the lateral horn the anterior/posterior rami. Link the the abdominopelvic viscera. Include the spinal levels cervical, brachial, and lumbosacral plexuses involved, the splanchnic nerves, the prevertebral (their contributing spinal levels) to this ganglia, and the effector organs. pathway. Include: 1. Contributing spinal levels 7. Describe the sympathetic innervation to the suprarenal 2. Path within the sympathetic trunk gland 3. Location of, and transition between, 8. Define Mass Activation and in what situation it occurs preganglionic and postganglionic neurons 9. Visually identify components of sympathetic ganglion (location of synapse) 4. Type of effect on skin histologically 10. Describe the development of the sympathetic division Sympathetic Nervous System  Sympathetic Visceral Motor Where will UMN start? Which diencephalic structures will play an important roll?  Preganglionic Neurons LO 3 Preganglionic Cell bodies located in intermediolateral cell columns Motor innervation will then leave (nuclei) of spinal cord from T1 to L2 spinal cord through anterior rootlets Intermediolateral columns- paired columns in the and travel to autonomic ganglia where thoracic and lumbar (T1- L2) segments of the spinal cord they synapse on postganglionic that form lateral horns* in gray matter neurons Organizes somatotopically; Ex., cell bodies that provide innervation for the head are superior and those for the lower limb are inferior Clinically Oriented Anatomy, Moore et al., 2018 Gray’s Basic Anatomy, Drake et al., 2018  LO 3 Postganglionic Neurons Cell bodies for postganglionic neurons located in 1. Paravertebral ganglia (sympathetic trunk/chain) 2. Prevertebral ganglia All sympathetic ganglia are close to the spinal cord → preganglionic fibers are short and postganglionic fibers are long to reach all parts of the body Clinically Oriented Anatomy, Moore et al., 2018  LO 3 Postganglionic Neurons Paravertebral ganglia- linked to form sympathetic trunks (chains) on each side of the vertebral column About one ganglia per vertebral body* *Cervical ganglia – only three; superior, middle and inferior ganglia Ganglion impar- inferior connection between two trunks at level of coccyx Gray’s Basic Anatomy, Drake et al., 2018  LO 3 Postganglionic Neurons Prevertebral ganglia – part of nerve plexuses that surround major branches of abdominal aorta Ganglia named for arterial branches they surround Celiac ganglia- surround celiac trunk Superior mesenteric ganglia- superior mesenteric artery Aorticorenal ganglia- renal arteries Inferior mesenteric ganglia- inferior mesenteric artery Clinically Oriented Anatomy, Moore et al., 2018 Sympathetic Divisions (What?!?! More divisions?!?)  LO 4/5 Sympathetic Nervous System Divisions Parietal Division Visceral Division Provides visceral motor Provides visceral motor to innervation to glands and organs of the thoracic and smooth muscles in skin abdominopelvic cavities Sweat glands Receives visceral sensory from Smooth muscle in vessels thoracic and abdominal pelvic Arrector pili muscles organs Parietal Division  LO 4 Sympathetic Divisions: Parietal Glands and smooth muscles in skin allow for: Vasomotion (vasocontriction/dilation) Sudomotion (sweat) Pilomotion (goose-bumps) All preganglionic fibers synapse in sympathetic trunk ganglia; then travel with anterior or posterior rami of spinal nerves in peripheral nerves to innervate associated dermatome Gray’s Basic Anatomy, Drake et al., 2018  LO 4-6 General Pathway preganglionic neurons 1. Intermediolateral column/nuclei 2. Anterior root 3. Spinal nerve 4. Anterior rami 5. Enter white rami communicans (only located in T1-L2 level of spinal cord- why? 6. Enter sympathetic trunk Gray’s Basic Anatomy, Drake et al., 2018  LO 4 Depending on the dermatome, pathway in sympathetic trunk will vary Enter, synapse on postganglionic neurons, then leave at same level Enter, travel superiorly, synapse on postganglionic neurons, leave Enter, travel inferiorly, synapse on postganglionic neurons, leave  LO 4 Parietal Sympathetic Pathways In sympathetic trunk A. Enter, synapse immediately, leave via gray rami communicans Travel through anterior/posterior ramus T1 to L2 – Thorax, superior thigh B. Ascend sympathetic trunk, synapse, leave via gray rami communicans Anterior/posterior ramus C. Descend sympathetic trunk, synapse, leave via gray rami communicans Anterior ramus Gray’s Basic Anatomy, Drake et al., 2018  LO 4 Parietal Sympathetic Pathways In sympathetic trunk A. Enter, synapse immediately, leave via gray rami communicans Travel through anterior/posterior ramus T1 to L2 - Thorax, superior thigh B. Ascend sympathetic trunk, synapse, leave via gray rami communicans Anterior/posterior ramus C2 to C8 - Head, neck, and upper limb C. Descend sympathetic trunk, synapse, leave via gray rami communicans Anterior ramus (why no posterior rami?) L3 to Co – Lower limb Gray’s Basic Anatomy, Drake et al., 2018 Visceral Division  LO 5/6 Sympathetic Divisions: Visceral Visceral sensory and motor to blood vessels and organs of the thoracic and abdominopelvic cavities Viscera of head Thoracic viscera Abdominopelvic viscera  LO 5 Visceral Division- Possible Pathways Splanchnic nerves: convey Enter sympathetic trunk: autonomic fibers to and from the a. Synapse immediately in viscera of the body cavities paravertebral ganglia OR b. Ascend trunk then synapse in paravertebral ganglia Then Travel to organ via splanchnic nerves Only for abdominal and pelvic viscera c. Pass/travel through trunk without synapsing, travel through splanchnic nerves, synapse in prevertebral ganglia, travel to organ Gray’s Basic Anatomy, Drake et al., 2018  Head and Neck Viscera LO 5 Contributions from spinal level T1 Preganglionic fibers enter sympathetic trunk, Ascend then synapse in superior cervical ganglia (uppermost paravertebral Sympathetic trunk ganglion) Postganglionic fibers exit trunk via the cephalic arterial ramus (fancy name for gray ramus) Travels along internal carotid artery to form internal carotid plexus Dilator of pupil, blood vessels, glands (pineal, salivary, lacrimal), and carotid body Clinically Oriented Anatomy, Moore et al., 2018  LO 5 Thoracic Organs Sympathetic innervation to heart and lungs. Sympathetic trunk Contribution from spinal levels T1-T5 Ascend to superior, middle, or inferior cervical ganglia then synapse OR Synapse at level in paravertebral ganglia T1-T5 Postganglionic fibers form cardiopulmonary splanchnic nerves Clinically Oriented Anatomy, Moore et al., 2018  LO 5 Cardiopulmonary Splanchnic Nerves 1. Superior cervical ganglion Heart 2. Middle cervical ganglion* Sympathetic trunk Heart *Sometimes absent 3. Inferior cervical ganglion* Heart *Sometimes fuses with first thoracic ganglia 4. Paravertebral ganglia T1-T5 Heart and lungs Clinically Oriented Anatomy, Moore et al., 2018  LO 1 1 Gross Anatomy 2 1. Superior cervical ganglion 3 2. Middle cervical ganglion 3. Inferior cervical ganglion (Stellate ganglion) 4. Thoracic paravertebral 4 ganglion  LO 6 Abdominal and Pelvic Viscera 1. Pass through sympathetic trunk (T5 to L2) without synapsing* 2. Travel through splanchnic nerves 3. Synapse in prevertebral ganglia 4. postganglionic axons supply organs in the abdomen and pelvis *some axons may exit at that level, or travel inferiorly before exiting Gray’s Basic Anatomy, Drake et al., 2018  LO 6 Abdominopelvic Splanchnic Nerves Splanchnic nerves (spinal nerves T5- L2) Greater thoracic (T5-T9) Lesser thoracic (T10, T11) Least thoracic (T12) Lumbar (L1-L2/3) Splanchnic nerves synapse on prevertebral ganglia named for surrounding vessels Greater→ Celiac Lesser→ Aorticorenal Least→ Superior mesenteric Lumbar→ Inferior mesenteric Postganglionic fibers travel to organ Clinically Oriented Anatomy, Moore et al., 2018  LO 6 Prevertebral Ganglia Prevertebral ganglia are not paired Located only in abdominal cavity 1. Spinal nerves T5-T9→ Greater splanchnic nerve→ Celiac ganglion Stomach, liver, gallbladder, pancreas, spleen 2. Spinal nerves T10-T11→ Lesser splanchnic nerve → Aorticorenal ganglion Suprarenal gland, kidney 3. Spinal nerve T12→ Least splanchnic nerve→ Superior mesenteric ganglion Small intestine, proximal large intestine 4. Spinal nerve L1-L2/3→ Lumbar splanchnic nerve→ Inferior mesenteric ganglion Distal large intestine, rectum, urinary bladder, distal ureters, most reproductive organs Clinically Oriented Anatomy, Moore et al., 2018  Celiac ganglia LO 1 Gross Anatomy Celiac trunk stomach Aorta Superior mesenteric kidney Celiac ganglion ganglion Celiac trunk Aorticorenal Superior mesenteric ganglion aorta Aorticorenal ganglion artery Renal Renal arteries artery Inferior Superior mesenteric ganglion mesenteric Inferior ganglion Superior mesenteric artery mesenteric artery Inferior mesenteric ganglion Inferior mesenteric artery Posterior wall Prevertebral ganglia of abdominal cavity  LO 7 The Exception: Suprarenal Gland preganglionic sympathetic fibers pass through prevertebral ganglia without synapsing Terminate on cells of suprarenal medulla (innermost portion of gland) Suprarenal medulla cells function as postganglionic neurons, releasing neurotransmitters into bloodstream causing a widespread sympathetic response Clinically Oriented Anatomy, Moore et al., 2018  LO 8 Mass Activation Simultaneous innervation of Cause many effector organs Heightened sense of alertness Increased heart rate, blood pressure, Occurs during an emergency or respiration, and breathing rate crisis situation Pupil dilation Numerous branches of preganglionic sympathetic axons synapse in many ganglia, which synapse with many postganglionic neurons, to many effector organs Histology and Development  LO 9 Sympathetic Histology Neuron cell body Autonomic ganglion Satellite cells Neurolemmocytes (Schwann cells)  LO 10 Development of the Sympathetic Division Week 5 Neural crest cells migrate along spinal cord to form masses on either side of aorta Form sympathetic trunk with paravertebral ganglia located at level of vertebral bodies Other neural crest cells migrate to anterior/ventral side of aorta to form prevertebral ganglia or near organs to form associated plexuses  LO 10 Development of the Sympathetic Division Week 5+ Axons will grow from the lateral horns (T5- L2 only) into the PNS, tracing the same route the pathways travel after development Motor axons grow from intermediolateral cell column, through anterior root of spinal nerve, white ramus communicans, to paravertebral ganglia A. Ascend and synapse (exit via gray ramus communicant or cephalic arterial branch) B. Synapse at level (exit via gray ramus communicantes) C. Descend and synapse (exit via gray ramus communicantes) D. Pass through paravertebral ganglia to prevertebral ganglia then form splanchnic nerves