ANAT30008 Autonomic Nervous System PDF

Review of Autonomic Nervous System Professor Jason Ivanusic Room E724 7th Floor, East Wing, Medical Building Email: [email protected] Phone: 83447254  WARNING This material has been provided to you pursu...

Review of Autonomic Nervous System Professor Jason Ivanusic Room E724 7th Floor, East Wing, Medical Building Email: [email protected] Phone: 83447254  WARNING This material has been provided to you pursuant to section 49 of the Copyright Act 1968 (the Act) for the purposes of research or study. The contents of the material may be subject to copyright protection under the Act. Further dealings by you with this material may be a copyright infringement. To determine whether such a communication would be an infringement, it is necessary to have regard to the criteria set out in Part 3, Division 3 of the Act.  Nervous system Somatic Autonomic Sensory to body walls, Innervation of viscera, blood vessels, limbs, skin glands and smooth muscle Motor to skeletal muscle “Subconscious” or “involuntary” “Conscious” or “voluntary” Two neurons from spinal cord to target Sensory Motor Sympathetic Parasympathetic Perceivable stimuli Skeletal muscle Thoraco-lumbar Cranio-saccral Touch Movement Mobilize body energies Conserve body energies Pressure Fight or flight Bronchoconstriction Pain Bronchodilation Decrease in heart rate Vasoconstriction in skin Increase in glandular secretions Increase in heart rate Decreases sweating Decrease in glandular Increase in GIT motility secretions Visceral sensory neurons? Increases sweating Decrease in GIT motility  Somatic neurons (skin and skeletal muscle) Somatic sensory neurons: Bring information about touch, pressure and pain from the periphery to the CNS Somatic motor neurons: Carry information from the CNS to skeletal muscles for Author’s own movement  Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1- 929007-15-9, Plate #150 Spinal cord Dermatomes Ventral ramus of spinal nerve Netter, F.H. Interactive Atlas of Dorsal ramus of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1- Dorsal root spinal nerve 929007-15-9, Plate #156A ganglion Autonomic neurons Cervical ganglia Brainstem Sympathetic Mobilize body energies “Fight or flight” Thoraco-lumbar Short preganglionic fibres Synapse with postganglionic fibres in sympathetic trunk (head and thorax) or prevertebral/visceral ganglia (abdomen) Run along through cervical ganglia and vasculature to get to viscera in the head, or splanchnic nerves to get to abdominal and pelvic viscera Spinal cord Sympathetic trunk Nolte, J. The Human Brain. 5th ed., St. Louis, Mosby, 2002, ISBN: 0-323-01320-1, Figure 10.26  Sympathetic neurons Sympathetic preganglionic (myelinated/white) Sympathetic postganglionic (unmyelinated/grey) Author’s own  Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Spinal nerve Icon Learning Systems, 2003, ISBN: 1- 929007-15-9, Plate #179 Sympathetic ganglion Prevertebral ganglia Sympathetic (visceral) ganglion Rami communicantes Sympathetic ganglion (paravertebral) Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1- Netter, F.H. Interactive Atlas of Human 929007-15-9, Plate #156A Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1- 929007-15-9, Plate #250 Segmental organization of sympathetic neuron output Nolte, J. The Human Brain. 5th ed., St. Louis, Moore, Dalley, Agur. Clinically Oriented Anatomy. 6th ed. Lippincott Mosby, 2002, ISBN: 0-323-01320-1, Figure 10.26 Williams and Wilkins; 2010. ISBN 978-1-60547-652-0. p.304, fig 2.90 Autonomic neurons Brainstem Cervical ganglia Vagus nerve (CNX) Parasympathetic Conserve body energies Cranio-sacral Long preganglionic fibres (run in cranial nerves including Vagus nerve for thorax and abdomen, or pelvic splanchnic nerves for pelvis) Synapse with postganglionic fibers near viscera Spinal cord Nolte, J. The Human Brain. 5th ed., St. Louis, Mosby, 2002, ISBN: 0-323-01320-1, Figure 10.26 Visceral afferent (sensory) neurons Visceral afferent neuron - Sensory to viscera - Distension of viscera - Visceral pain - follows sympathetic pathways back to CNS - can also follow parasympathetic pathways back to CNS Anatomedia  Referred pain Referred pain is the perception of pain in areas other than the site of stimulation, usually due to a common spinal segmental origin of the nerves to the site of stimulation and the site to which the pain is referred. Probably due to convergence of the two inputs to the same population of neurons at a given spinal segmental level. Visceral pain is usually referred to somatic regions. Somatic pain can be referred to other somatic regions. Author’s own Somatic afferent nerve fiber Visceral afferent nerve fiber Visceral afferent (sensory) neurons Visceral afferent neuron - Sensory to viscera - Distension of viscera - Visceral pain - follows sympathetic pathways back to CNS - can also follow parasympathetic pathways back to CNS Anatomedia Predicting patterns of referred pain from specific viscera Visceral sensory neurons travel through same pathways as sympathetic neurons to spinal cord Thus segmental innervation of sympathetic innervation to any given viscera can be used to predict spinal cord segment where convergence occurs, and therefore which dermatomes pain is referred to. Author’s own Moore, Dalley, Agur. Clinically Oriented Anatomy. 6th ed. Lippincott Williams and Wilkins; 2010. ISBN 978-1-60547-652-0. p.304, fig 2.90 Somatic afferent Visceral afferent nerve fiber nerve fiber Referred pain from paired viscus Pain from paired viscus referred to skin on same side Because visceral sensory neuron enters spinal cord segment from one side From Anatomedia: General Anatomy Unpaired viscera GI tract + associated glands & ducts – develop in midline but migrate away from it (associated orifices - mouth, anal canal remain in midline) Nerve supply from both sides of spinal cord Visceral pain referred to midline skin (over origin of viscus) because dual visceral sensory nerve supply reaches both sides of spinal cord simultaneously From Anatomedia: General Anatomy Presentation of pain can change as disease progresses or changes From Anatomedia: General Anatomy