Spinal Nerves and Reflexes
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Let's Form a Reflex Arc Model
Journal of Inquiry Based Activities (JIBA) /Araştırma Temelli Etkinlik Dergisi (ATED) Vol 9, No 2, 84-95, 2019 LET’S FORM A REFLEX ARC MODEL: A STEM ACTIVITY1 Ayşegül Kağnıcı2, Özlem Sadi3 ABSTRACT The purpose of this study is to introduce an activity which has been designed in accordance with Science, Technology, Engineering, Mathematics (STEM) education within the scope of 5E learning model and to present the implementation steps of it. The activity plan is on the topics of Nerves, Hormones and Homeostasis in Human Physiology Unit in 11th grade biology curriculum. The activity was implemented with the participation of 49 students at a public high school. For the implementation of the activity, the students were divided into groups of five and they tried to complete the activity in four class hours. The participant students stated that they both learned and enjoyed learning while they were creating their model. Moreover, the teachers who implemented the activity stated that the equipment used in the activity is easy to access, which creates an advantage for the activity to be done in class. Keywords: biology education, reflex arc, STEM, nervous system. REFLEKS YAYI MODELİ OLUŞTURALIM: BİR STEM ETKİNLİĞİ ÖZ Bu çalışmanın amacı STEM eğitimine uygun olarak tasarlanan bir etkinliğin 5E öğrenme modeli kapsamında tanıtılması ve uygulama basamaklarının sunulmasıdır. Etkinlik planı, 11. Sınıf Biyoloji Dersi Öğretim Programında bulunan İnsan Fizyolojisi ünitesindeki Sinirler, Hormonlar ve Homeostazi konusu ile ilgilidir. Etkinliğin özellikle, omuriliğin görevleri ile refleks yayının çalışma mekanizmalarının öğrenilmesi noktasında faydalı olacağı düşünülmüştür. Etkinlik, bir devlet lisesinde öğrenim gören 49 öğrencinin katılımıyla gerçekleştirilmiştir. Etkinliğin uygulanmasında öğrenciler beşer kişilik gruplar oluşturmuş ve dört ders saati boyunca etkinliği tamamlamaya çalışmışlardır. -
Clinical Presentations of Lumbar Disc Degeneration and Lumbosacral Nerve Lesions
Hindawi International Journal of Rheumatology Volume 2020, Article ID 2919625, 13 pages https://doi.org/10.1155/2020/2919625 Review Article Clinical Presentations of Lumbar Disc Degeneration and Lumbosacral Nerve Lesions Worku Abie Liyew Biomedical Science Department, School of Medicine, Debre Markos University, Debre Markos, Ethiopia Correspondence should be addressed to Worku Abie Liyew; [email protected] Received 25 April 2020; Revised 26 June 2020; Accepted 13 July 2020; Published 29 August 2020 Academic Editor: Bruce M. Rothschild Copyright © 2020 Worku Abie Liyew. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Lumbar disc degeneration is defined as the wear and tear of lumbar intervertebral disc, and it is mainly occurring at L3-L4 and L4-S1 vertebrae. Lumbar disc degeneration may lead to disc bulging, osteophytes, loss of disc space, and compression and irritation of the adjacent nerve root. Clinical presentations associated with lumbar disc degeneration and lumbosacral nerve lesion are discogenic pain, radical pain, muscular weakness, and cutaneous. Discogenic pain is usually felt in the lumbar region, or sometimes, it may feel in the buttocks, down to the upper thighs, and it is typically presented with sudden forced flexion and/or rotational moment. Radical pain, muscular weakness, and sensory defects associated with lumbosacral nerve lesions are distributed on -
The Reflex Arc: How a Stimulus Elicits a Response
The Reflex Arc How a Stimulus Elicits a Response A Knee-Jerk Response • What happened? • When the hammer hit the knee the foot jerked up. • Why? Reacting to Changes • You need to keep the conditions inside your body constant. Doing this is called homeostasis. Small changes inside your body can cause its cells to be damaged or destroyed. Yet, there are big changes going on outside your body. • You need to detect a change in the environment (a stimulus) and react to the change (a response) in a way that maintains homeostasis. When you do this without thinking, it is called a reflex. Reacting to Changes • It can get very hot or very cold outside, but the temperature inside your body stays the same. How? • When it gets cold outside (stimulus) you shiver (response) and keep the temperature inside your body from dropping. • When it gets hot outside (stimulus) you perspire (response) and keep the temperature inside your body from rising. Posture • In order to maintain your posture (even bad posture - stop slouching) your muscles are constantly monitoring their shape. A change in shape of a muscle (the stimulus) causes the muscle to readjust its shape (the response) and maintain your posture. • The knee-jerk reflex is base on the hammer changing the shape of a muscle. Revisiting the Knee-Jerk Response • What is the stimulus? The hammer hits the tendon. • What is the response? The muscle contracts, causing the foot to jerk upward. Other Reflexes Stimulus Response The aroma of your favorite Salivation food A nasty odor Nausea A bright light shining in your Pupils get smaller eye An insect flying towards your Blinking eye How is a Stimulus Detected? • Some cells are specialized to react to a specific stimulus. -
Spinal Nerves, Ganglia, and Nerve Plexus Spinal Nerves
Chapter 13 Spinal Nerves, Ganglia, and Nerve Plexus Spinal Nerves Posterior Spinous process of vertebra Posterior root Deep muscles of back Posterior ramus Spinal cord Transverse process of vertebra Posterior root ganglion Spinal nerve Anterior ramus Meningeal branch Communicating rami Anterior root Vertebral body Sympathetic ganglion Anterior General Anatomy of Nerves and Ganglia • Spinal cord communicates with the rest of the body by way of spinal nerves • nerve = a cordlike organ composed of numerous nerve fibers (axons) bound together by connective tissue – mixed nerves contain both afferent (sensory) and efferent (motor) fibers – composed of thousands of fibers carrying currents in opposite directions Anatomy of a Nerve Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Epineurium Perineurium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Endoneurium Nerve Rootlets fiber Posterior root Fascicle Posterior root ganglion Anterior Blood root vessels Spinal nerve (b) Copyright by R.G. Kessel and R.H. Kardon, Tissues and Organs: A Text-Atlas of Scanning Electron Microscopy, 1979, W.H. Freeman, All rights reserved Blood vessels Fascicle Epineurium Perineurium Unmyelinated nerve fibers Myelinated nerve fibers (a) Endoneurium Myelin General Anatomy of Nerves and Ganglia • nerves of peripheral nervous system are ensheathed in Schwann cells – forms neurilemma and often a myelin sheath around the axon – external to neurilemma, each fiber is surrounded by -
Hand on a Hot Stove
Hand on a Hot Stove Introduction: When You Put Your Hand on a Hot Stove Think about what happens if you accidentally place your hand on a hot stove. Use numbers 1-5 to place these statements in the order in which they happen. ____ You wave or shake your hand voluntarily to cool it. ____ Your arm moves to automatically move your hand away from the stove. ____ You feel pain in your hand. ____ You remember that you should not touch a hot stove. ____ You touch a hot stove. Life Sciences Learning Center 1 Copyright © 2013 by University of Rochester. All rights reserved. May be copied for classroom use Part 1: What is a reflex? Reflexes If you touch something that is very hot, your hand moves away quickly before you even feel the pain. You don’t have to think about it because the response is a reflex that does not involve the brain. A reflex is a rapid, unlearned, involuntary (automatic) response to a stimulus (change in the environment). Reflexes are responses that protect the body from potentially harmful events that require immediate action. They involve relatively few neurons (nerve cells) so that they can occur rapidly. There are a wide variety of reflexes that we experience every day such as sneezing, coughing, and blinking. We also automatically duck when an object is thrown at us, and our pupils automatically change size in response to light. These reflexes have evolved because they protect the body from potentially harmful events. Most reflexes protect people from injury or deal with things that require immediate action. -
A Step Towards Stereotactic Navigation During Pelvic Surgery: 3D Nerve Topography
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Erasmus University Digital Repository Surgical Endoscopy and Other Interventional Techniques https://doi.org/10.1007/s00464-018-6086-3 A step towards stereotactic navigation during pelvic surgery: 3D nerve topography A. R. Wijsmuller1,2 · C. Giraudeau3 · J. Leroy4 · G. J. Kleinrensink5 · E. Rociu6 · L. G. Romagnolo7 · A. G. F. Melani7,8,9 · V. Agnus2 · M. Diana3 · L. Soler3 · B. Dallemagne2 · J. Marescaux2 · D. Mutter2 Received: 10 May 2017 / Accepted: 1 February 2018 © The Author(s) 2018. This article is an open access publication Abstract Background Long-term morbidity after multimodal treatment for rectal cancer is suggested to be mainly made up by nerve- injury-related dysfunctions. Stereotactic navigation for rectal surgery was shown to be feasible and will be facilitated by highlighting structures at risk of iatrogenic damage. The aim of this study was to investigate the ability to make a 3D map of the pelvic nerves with magnetic resonance imaging (MRI). Methods A systematic review was performed to identify a main positional reference for each pelvic nerve and plexus. The nerves were manually delineated in 20 volunteers who were scanned with a 3-T MRI. The nerve identifiability rate and the likelihood of nerve identification correctness were determined. Results The analysis included 61 studies on pelvic nerve anatomy. A main positional reference was defined for each nerve. On MRI, the sacral nerves, the lumbosacral plexus, and the obturator nerve could be identified bilaterally in all volunteers. The sympathetic trunk could be identified in 19 of 20 volunteers bilaterally (95%). -
The-Nervous-System-3.Pdf
Kingsmead Technology College Q1. Reflex actions are rapid and automatic. (a) Name the following structures in a reflex action. (i) The structure that detects the stimulus. ........................................................................................................................... (1) (ii) The neurone that carries impulses to the central nervous system. ........................................................................................................................... (1) (iii) The neurone that carries impulses away from the central nervous system. ........................................................................................................................... (1) (iv) The structure that brings about the response. ........................................................................................................................... (1) (b) Describe what happens at a synapse when an impulse arrives. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... -
35. Lumbar Plexus. Sacral Plexus. Coccygeal Plexus
GUIDELINES Students’ independent work during preparation to practical lesson Academic discipline HUMAN ANATOMY Topic LUMBAR PLEXUS. SACRAL PLEXUS. COCCYGEAL PLEXUS 1. Relevance of the topic Lumbar, sacral and coccygeal plexuses innervate the skin of the abdomen, lower back and lower extremities and all the muscles of the lower limbs. Acquired knowledge is the basis for many fields of practical medicine, such as neurology, surgery and traumatology. 2. Specific objectives After the lesson the student should know and be able to: - describe the sources of the formation of the lumbar plexus; - classify the nerves of the lumbar plexus; - to be able to demonstrate and define the branches of the lumbar plexus; - describe sources of sacral plexus formation; - classify sacral plexus nerves; - be able to demonstrate and identify short and long branches of the sacral plexus; - describe the sources of formation coccygeal plexus; - classify coccygeal plexus nerves; - be able to demonstrate and identify branches of coccygeal plexus; - to explain the innervation of muscles and skin in the areas of the lower back and lower extremity. 3. Basic level of preparation For practical this lesson a student should know and be able: - to know the anatomy of the spine, pelvis, lower extremities; - to analyze and show large and small pelvis, their bones; - to analyze and demonstrate bones and joints of the lower limbs; - to demonstrate muscles of the abdomen, perineum, pelvic girdle and lower limbs; - to know the anatomy (external and internal structure) of the spinal cord; - to know the spinal nerve anatomy. 4. Tasks for independent work during preparation for the classes 4.1. -
Management of Metastatic Tumors Invading the Peripheral Nervous System
Neurosurg Focus 22 (6):E14, 2007 Management of metastatic tumors invading the peripheral nervous system JOHN GACHIANI, M.D.,1 DANIEL H. KIM, M.D.,3 ADRIANE NELSON, M.D.,2 AND DAVID KLINE, M.D.1 Departments of 1Neurosurgery and 2Pathology, Louisiana State University Health Sciences Center; 3Department of Neurosurgery, Ochsner Clinic Foundation, New Orleans, Louisiana Object. The authors present the results of a retrospective review of 37 surgically treated metastases to nerve (malignant peripheral non–neural sheath nerve tumors). Tumor frequencies, presentations, management, and prognosis are discussed. Methods. Thirty-seven patients who were treated for metastases to nerve between 1969 and 2006 at the Louisiana State University Health Sciences Center were identified in a review of patient records. Notes regarding patient history and physical examination findings were reviewed to provide informa- tion on presenting symptoms and signs. Imaging and histopathological examination results were also reviewed. Cases were analyzed depending on the primary tumor and the location of metastasis. Results. There included 37 surgically treated lesions, 16 of which originated in the breast and 10 of which originated in the lung. In two cases melanomas had metastasized to nerve, and one tumor each had metastasized from the bladder, rectum, skin, head and neck, and thyroid, and from a primary Ewing sarcoma. There was a single lymphoma that had metastasized to the radial nerve and one chor- doma and one osteosarcoma, each of which had metastasized to the brachial plexus. Conclusions. The nervous system is involved in numerous ways by oncological process. Direct involvement of the peripheral nervous system occurs mostly from direct extension, although it occa- sionally occurs because of distant spread from the primary tumor to nerve. -
The Nervous System Reflexes Spinal Reflexes Reflex Arc the Stretch
1/17/2016 Reflexes • Rapid, involuntary, predictable motor response to a stimulus The Nervous System Spinal Reflexes Spinal Reflexes Reflex Arc • Spinal somatic reflexes • Components of a reflex arc – Integration center is in the spinal cord 1. Receptor—site of stimulus action – Effectors are skeletal muscle 2. Sensory neuron—transmits afferent impulses to the CNS • Testing of somatic reflexes is important clinically 3. Synapses in gray matter—either monosynaptic or to assess the condition of the nervous system polysynaptic region within the CNS 4. Motor neuron—conducts efferent impulses away from cord • Identical stimulus should always elicit the same 5. Effector—muscle fiber or gland cell that responds to response stereotyped reflex the efferent impulses by contracting or secreting Stimulus The Stretch Reflex Skin • Monosynaptic reflex – 2 neurons (sensory and motor), 1 synapse 1 Receptor Interneuron • Muscle spindles 2 Sensory neuron – Sensory receptors in belly of muscle 3 Integration center – Detects changes in length of muscle 4 Motor neuron • Muscle is stretched, reflex reverses the stretch 5 Effector • Important for coordination, maintenance of posture, keeps muscles from over stretching Spinal cord (in cross section) Figure 13.14 1 1/17/2016 Secondary sensory The patellar (knee-jerk) reflex—a specific example of a stretch reflex Efferent (motor) endings (type II fiber – fiber to muscle spindle senses when muscle 2 is still) Quadriceps 3a (extensors) 3b 3b ααα Efferent (motor) 1 Primary sensory fiber to extrafusal Patella endings (type Ia Muscle Spinal cord muscle fibers spindle Fiber – senses (L 2–L4) stretching) Extrafusal muscle 1 Tapping the patellar ligament excites fiber Hamstrings Patellar muscle spindles in the quadriceps. -
BOOK REVIEW Central Nerve Plexus Injury
Spinal Cord (2009) 47, 271–272 & 2009 International Spinal Cord Society All rights reserved 1362-4393/09 $32.00 www.nature.com/sc BOOK REVIEW Central nerve plexus injury Carlstedt T even though the book was published in 2007, only about 10% Central Nerve Plexus Injury, London, Imperial College Press, 2007, of the references listed in this chapter were published after 192 pages, US $128.00 2000, and the most recent papers were published in 2004. ISBN-10: 1860945732; ISBN-13: 978-1860945731 In Chapter 7, the author describes his approach to managing the brachial and lumbosacral plexuses. His Spinal Cord (2009) 47, 271–272; doi:10.1038/sc.2008.111 descriptions of surgical procedures are well written. How- ever, the quality of the photographs of surgical procedures is The fact that neurons from the central nervous system can less than satisfactory in most instances. regenerate into peripheral nerves has been known for a long In Chapter 8, Dr Carlstedt describes his experiences with time.1 Now,inhisbook,DrCarlstedtappliesthisconceptto intradural root repair in a limited series of patients. He repair avulsion injuries of the brachial and lumbosacral plexus. attributes any and all recovery experienced by these patients In Chapter 1 of his book, Dr Carlstedt briefly describes the to the spinal procedure and then challenges the axiom that history of brachial plexus repair, up to his first cases of root normal function cannot be restored after any procedure in reimplantation into the spinal cord. the brachial plexus, excluding neurolysis. The fact that he In Chapter 2, he reviews the mechanisms and patterns of fails to consider other nonsurgical sources of recovery within root avulsion, reinforcing the concept that the lower roots of his small series of patients is disturbing. -
Myelin Sheaths Myelin Sheaths in the PNS
Myelin Sheaths Myelin Sheaths in the PNS • Segmented structures composed of the • Formed by Schwann cells lipoprotein myelin • Develop during fetal period and in the first • Surround thicker axons year of postnatal life • Form an insulating layer • Schwann cells wrap in concentric layers • Prevent leakage of electrical current around the axon • Increase the speed of impulse conduction • Cover the axon in a tightly packed coil of membranes • Neurilemma • Material external to myelin layers Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. Myelin Sheaths in the PNS Unmyelinated Axons in the PNS (a) Myelinated axon in PNS (b) Unmyelinated axons in PNS An axon wrapped with a fatty insulating sheath Axons that are not covered with an insulating sheath formed from Schwann cells Myelin sheath Schwann cell plasma membrane 1 A Schwann cell Schwann cell Schwann cell envelops an axon. Schwann cell cytoplasm cytoplasm Axon Axon Schwann cell Axons Schwann cell nucleus Neurilemma 1 A Schwann Neurilemma Schwann cell cell surrounds Axons nucleus multiple axons. 2 The Schwann cell then rotates around the axon, wrapping its plasma membrane loosely around Cross section of a myelinated axon (TEM 30,000×) it in successive layers. Cross section of unmyelinated axons (TEM 11,000×) 3 The Schwann cell Neurilemma cytoplasm is forced from 2 Each axon is Myelin between the membranes. The encircled by the sheath tight membrane wrappings surrounding the axon form Schwann cell the myelin sheath. plasma membrane. Copyright © 2011 Pearson Education, Inc. Figure 12.7a Copyright © 2011 Pearson Education, Inc. Figure 12.7b Myelin Sheaths in the PNS Myelin Sheaths in the CNS • Nodes of Ranvier—gaps along axon • Oligodendrocytes form the myelin sheaths • Thick axons are myelinated in the CNS • Myelination speeds up nerve transmission • Have multiple processes • Thin axons are unmyelinated • Coil around several different axons • Conduct impulses more slowly Copyright © 2011 Pearson Education, Inc.