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Chapter 7: Nervous System

This presentation covers the central and peripheral nervous systems, neurons, nervous tissue, sensory receptors, white and gray matter, nerve impulses, conductivity, and synapses.

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Chapter 7: Nervous System

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  1. NOTE: This presentation was not made for public use. Please do not use this presentations without my permission and the permission of each of the authors of the photographs, quotes, and other materials that they contain. Thank you, Vicki Hughes

  2. CHAPTER 7: NERVOUS SYSTEM We are doing chapter 7 before chapter 6.

  3. ? ! ? ! Nervous system = master control and communication Three functions: 1. Gathering Sensory input • Integration (interpretation and decision-making about the stimuli). 3. Effects a response – motor output.

  4. Organization of the Nervous System CNS:Central Nervous Systemincludes brain and spinal cord PNS:Peripheral Nervous Systemincludes all other nerves

  5. Anatomy of a Neuron Myelin Sheath Node of Ranvier

  6. Organization of the Nervous System Afferent (Sensory) Division: conveys impulses TO the CNS CNS Efferent (Motor) Division: conveys impulses FROM the CNS Subdivisions: Somatic/Voluntary and Autonomic/Involuntary

  7. Supporting Cells of the CNS Neuroglia (Glia) = nerve “glue” cells Astrocytes: • 50% of nerve tissue • protect neurons from harmful substances in blood

  8. Supporting Cells of the CNS Neuroglia (Glia) = nerve “glue” cells Oligodendrocytes: • produces myelin (protective covering)

  9. Supporting Cells of the CNS Extensions from the oligodendrocyte form myelin sheaths for axons within the central nervous system.

  10. Nervous Tissue Supporting Cells of the CNS Ependymal cells on the surface of the choroid plexus secrete cerebrospinal fluid. http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::500::500::/sites/dl/free/0073520713/462745/07_q10.swf::View%20this%20animation%20before%20answering%20this%20question

  11. Supporting Cells of the CNS Microglia found within the central nervous system are similar to macrophages in that they “eat” harmful substances. microglia

  12. Supporting Cells of the CNS Extensions from the Schwann cells form a myelin sheath called the neurilemma around each axon within the peripheral nervous system.

  13. Nervous Tissue Supporting Cells of the CNS Neuron cell bodies within ganglia are surrounded by satellite cells that nourish and protect the underlying neuron cell body.

  14. Anatomy of a Nerve Cell Dendrites conduct impulses toward the nerve cell body. Axons conduct impulses away from the nerve cell body.

  15. Anatomy of a Nerve Cell CNS clusters of nerve cells = nuclei PNS clusters of nerve cells = ganglia ganglion nuclei neuromedia.neurobio.ucla.edu eftlab.org

  16. Anatomy of a Nerve Cell Tracts = bundles of nerves in CNS Nerves = bundles of nerves in the PNS Tract Nerves spiltmartini.com

  17. Anatomy of a Nerve Cell Types of Sensory Receptors 1. Naked Nerve Endings = pain & temperature

  18. Anatomy of a Nerve Cell Types of Sensory Receptors 2. Meissner’s corpuscles = touch kushtush.com ttouchnorth.co.uk

  19. Anatomy of a Nerve Cell Types of Sensory Receptors 3. Pacinian corpuscle = deep pressure russiablog.org responsiblemarketing.com impactlab.net

  20. Anatomy of a Nerve Cell • Types of Sensory Receptors • Proprioceptors= • muscular stretching or tension zimbio.com webmd.com

  21. Anatomy of a Nerve Cell White matter = myelinated regions of the brain Gray matter = unmyelinated regions of the brain http://www.youtube.com/watch?v=N2iJF2I94pg

  22. Anatomy of a Nerve Cell White matter and gray matter in MRI scans: Comparing normal brain (left) with Huntington’s Diseased brain (right). radlink.com.sg wordadaywonder.com

  23. The Nerve Impulse • Major functional properties: • Irritability • …ability to respond to stimuli I am irritable! And…You are getting on my very last nerve!

  24. The Nerve Impulse Conductivity…ability to conduct electrical currents • Resting membrane – Na+ and K+ levels are equal Na+ Na+ Na+ Na+ Na+ Na+ K+ K+ K+ K+ K+ K+ Nerve impulses are “all-or-nothing” events.

  25. Conductivity The Nerve Impulse B. Depolarization starts – Na+ moves into nerve cell. Cell depolarizes (becomes too + inside)Action Potential is generated. Na+ Na+ Na+ Na+ Na+ Na+ Depolarization K+ K+ K+ K+ K+ K+ K+ ACTION POTENTIAL De = reversal

  26. Conductivity The Nerve Impulse C. Action potential is propagated. Na+ Na+ Na+ Na+ Na+ Na+ Depolarization K+ K+ K+ K+ K+ K+ K+ K+ K+ K+ K+ K+ K+ ACTION POTENTIAL

  27. Conductivity The Nerve Impulse Re = again D. REpolarization. REpolarization K+ Na+ K+ Na+ K+ Na+ K+ Na+ K+ Na+ K+ Na+ Back to equal! Too much + inside! Nerve Impulse http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html http://www.youtube.com/watch?v=90cj4NX87Yk

  28. The Nerve Impulse Saltatory conduction = fast, jumping motion that moves impulses along the nodes of Ranvier

  29. SYNAPSE = location where an axon ending meets with either a muscle or the dendrite of another neuron. Axon calcium channel NEUROTRANSMITTER = chemical like ACH that carries signals across the synaptic cleft SYNAPTIC VESICLE containing Acetylcholine (ACH) which is a neurotransmitter. Synaptic cleft = space between axon ending and receiving muscle tissue or the dendrite of another neuron. muscle tissue sodium channel receptor protein

  30. Action Potential Stimulation of Muscles: • An action potential arrives at a presynaptic terminal. • The Calcium ion channel opens releasing calcium ions into the presynaptic terminal. • Calcium ions cause the synaptic vesicles to move to the synaptic cleft. • The synaptic vesicle releases ACH neurotransmitter into the cleft. • ACH diffuses across the cleft and binds to ACH receptors on the muscle fiber membrane. • Sodium channels open and release sodium into the muscle. • The muscle membrane depolarizes and a postsynaptic action potential results. Ca+ Ca+ Ca+ Ca+ NA+ NA+ NA+ muscle tissue muscle tissue

  31. Reflexes Auto = self Reflex = rapid, predictable, involuntary response ReflexArc = neural pathway of a reflex (goes only one way) Autonomic reflexes regulate smooth muscles

  32. Reflexes Soma = body http://www.sumanasinc.com/webcontent/animations/content/reflexarcs2.html Somatic reflexes stimulate skeletal muscles

  33. Brain Stem About the size of a thumb in diameter and about 3 inches long. Made up of medulla, pons, and midbrain. rainbowrehab.com

  34. Brain Stem Midbrain = small part that relays impulses and controls reflexes for vision and hearing.

  35. Brain Stem Pons = rounded structure of mostly fiber tracts involved in the control of breathing. Pons = bridge

  36. Medula Oblongata = merges into spinal cord; regulates vital internal activities including heart rate, blood pressure, breathing, swallowing, vomiting, etc. Brain Stem

  37. Brain Cerebellum = Outer gray matter; inner white matter. Provides timing for skeletal muscle activity, controls balance, and equilibrium. Compared to “autopilot” because it constantly checks and adjusts. Ataxia = Clumsy and disorganized movements as a result of damage to the cerebellum. http://www.youtube.com/watch?v=-s77voH8nRI

  38. THE CNS Pushing the Limits: BRAIN POWER

  39. THE CNS

  40. Quiz Tomorrow! THE CNS

  41. BRAIN FUN! RIGHT BRAIN VS LEFT BRAIN http://homeworktips.about.com/library/brainquiz/bl_leftrightbrain_quiz.htm http://similarminds.com/brain.html What are your results? Are you right or left brained? What does it mean?

  42. Protection of CNS Meninges = three membranes covering the CNS structures (p 211) Duramater = outermost layer Dura = hard Mater = mother netterimages.com schools-wikipedia.org

  43. Arachnoid Mater = web-like middle layer commons.wikimedia.org Arachno = spider

  44. Pia Mater = innermost layer following folds commons.wikimedia.org pia = gentle

  45. Meningitis = inflammation of meninges OCTOBER 23, 2013 5:30 PM EST https://www.youtube.com/watch?v=FHLWnlrmKNg

  46. Cerebrospinal Fluid (CSF) = fluid surrounding the brain and spinal cord Continually made from blood plasma in choroid plexuses which hang from the “roof” of the brains ventricles. Circulates continuously by being produced and then drained back into blood plasma to keep a constant volume of about 150 ml. Function: protection Spinal Tap = sampling technique to test CSF. Hydrocephalus = “water on the brain” https://www.youtube.com/watch?v=xLaXXupyG4w

  47. BLOOD-BRAIN BARRIER Keeps neurons separated from blood-borne substances. Made of LEAST PERMEABLE capillaries in the body. Can’t keep out fats, respiratory gases, alcohol, nicotine, or anesthetics. vandenberg.af.mil

  48. Brain Injuries Traumatic Brain Injuries and Brain Dysfunctions Head injuries are the leading cause of accidental death in the USA. Concussion = slight injury, dizziness, brief loss of consciousness. http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000034&ptid=17 Contusion = marked tissue destruction, coma Cerebral Edema = swelling of the brain, death

  49. Stroke = cerebrovascular accident (CVA) occurs when circulation is cut off to the brain. http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000123&ptid=17 Aphasia = result of damage to left cerebral hemisphere, affects speech. motor aphasia = affects Broca’s area and loss of speech sensory aphasia = loss of understanding of language TIA = transient ischemic attack (mini-stroke)

  50. Parkinson’s Disease Interactive tutorial http://www.nlm.nih.gov/medlineplus/tutorials/parkinsonsdisease/htm/index.htm Parkinson’s Disease Treatment http://www.edheads.org/activities/brain_stimulation/

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