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Nervous System

Nervous System. James Chung, Claire Yang 8th grade D block April. 1. History of Brain. Start of Brain Aristotle’s Theory “Skull Holes” Phineas Gage Case. 2. The Start of Brains. 100 million years ago Formation of nerves Development of brains. 3. Aristotle’s Theory.

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Nervous System

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  1. Nervous System • James Chung, Claire Yang • 8th grade D block • April 1

  2. History of Brain • Start of Brain • Aristotle’s Theory • “Skull Holes” • Phineas Gage Case 2

  3. The Start of Brains • 100 million years ago • Formation of nerves • Development of brains 3

  4. Aristotle’s Theory • Didn’t understand the functions of the brain • Center of thought in the heart • Brain, the air conditioner 4

  5. Ancient Surgeries 5

  6. “Skull Holes” • Skulls of South Americans and others • Religion? Surgery? • The unbearable pain 6

  7. Phineas Gage Case 7

  8. Phineas Gage Case • Railroad foreman in Vermont • Injury • Effects of Injury • One of the most amazing recovery in the medical history - Pierced though his left cheek - Passed into the skull - Shattered the upper jaw - Passed behind the left eye - Pierced through the brain, making a 4-inch wide hole - Personality changes - easily aroused, violent - Physically move, talk, work 8

  9. Neurons • Structure • Types • Nerve impulse 9

  10. Neurons: Structures • Dendrites • Nerve cell body • Axon - Long, thin branches - Receives nerve impulse - Carries it to the cell body - Nerve fiber - Similar to other types of cells - Nucleus - Long, thick branches - Can have multiple tips - Carries nerve impulse out - Nerve fiber 10

  11. Bipolar nerve cell Multipolar nerve cell Pseudo-unipolar nerve cell - Short vs. Long - Multiple vs. Single Various Structures - Halfway vs. End • Axons • Cell body • Dendrites - Few vs. Thousands 11

  12. Myelinated vs. Unmyelinated Myelinated axon - Sheath composed of Schwann cells - Spinal cord & peripheral nerves Unmyelinated axon - No sheath - Brain • Myelinated axon vs. Unmyelinated axons • Myelin • Characteristics of myelinated neuron • Characteristics of unmyelinated neuron - Fatty substance of Schwann cells’ membrane - Wraps around the axon - Prevention of leakage & weakening - Increase in speed - Possible leakage & weakening - Slower speed 12

  13. Neurons: Types • Sensory neuron (Receptor) • Interneuron (Link) • Motor neuron (Execution) - Peripheral nerves - Picks up stimuli signal - Packaging of stimulus into nerve impulses - Present in spinal cord & brain - Sensory neurons to motor neurons - Interpreting nerves impulses - Receives nerve impulses from interneurons - Sends nerve impulses to muscles or glands 13

  14. Nerve impulse: Transmission I • Travel within a neuron • Possible receivers - Travel along cell membrane - Electrical signals 0.1 volt Thousandth of sec. - Electric conduction Ion movements Ion pumps on cell membrane - Dendrite of another neuron - Muscle or cell in another organ - Can be fired or not 14

  15. Nerve impulse: Transmission II - Junction - One structure to another: Chemicals Within a neuron: Electrical signals • Synapse • Synaptic end bulb • Receptors of another structure - Release of neurotransmitters - Neurotransmitters - Synaptic cleft Gap: one hundredth of a hair - Neurotransmitters land on the receptors - Recycled neurotransmitters Vesicles Fun Fact - Scientists asked these following questions during their initial research on neurons: How do neurons use electricity and chemicals? - Squid Large neuron (compared to the neurons of other organisms) 15

  16. Neurons and How They Work • http://video.google.com/videosearch?client=safari&rls=en-us&q=neuron&oe=UTF-8&um=1&ie=UTF-8&sa=N&hl=en&tab=wv# 16

  17. Nervous System Divisions • Central Nervous System • Peripheral Nervous System • Autonomic System • Somatic System • Sympathetic System • Parasympathetic System 17

  18. Nervous System: Divisions * Click on different nervous system divisions to learn more Nervous System Peripheral Nervous System Central Nervous System Somatic System Spinal Cord Autonomic System Brain Sympathetic System Parasympathetic System 18

  19. Central Nervous System • Roles of Central Nervous System • Brain • Spinal cord - Control system of the body - External & internal environment information - Controls most of the body functions - Interprets nerve impulses - Response to stimuli - Thick column of nervous tissue - Link between the brain & peripheral nerves - Carries impulses to the brain & peripheral nervous system 19

  20. Parts of Brains & Functions I • Cerebrum • Movement, Touch, Reading, Taste, Speech, Hearing, Abstract thought, smell, vision - Largest part - Controls movement, senses, speech, abstract thought 20

  21. Parts of Brains & Functions II • Cerebellum • Brain stem • Medulla oblongata • Pons - Controls involuntary actions Ex. breathing, heart rate - Coordinates muscles - Maintain balance - Breathing, blood pressure - Sensory information between cerebrum and cerebellum 21

  22. Emotions and Amygdala • Amygdala - Controls modulation of memory consolidation 22

  23. Fear and Anxiety • Scared by external stimuli • Stop what they are doing • Threat? • Flight vs. Fight 23

  24. How to Ruin Your Brain I • Eat a lot*Eating too much can increase the brain vessel which will weaken your mental strength • Smoking*smoking would make you forget things, and get distracted easily • Sugareating too much sugar can result in blocking the development of the brain 24

  25. How to Ruin Your Brain II • Poor sleep*sleeping gives the brain a time to rest. Sleeping less can result in brain not functioning well • Lack of Thinking*less thinking can result in brain shrink 25

  26. Did you Know... • 350-400 grams of brain weight for new born babies1300-1400 grams of brain weight for adults • stegosaurus dinosaur weighed approximately 1,600 kg but had a brain that weighed only approximately 70 grams (0.07 kg) [0.004 % of the total body weight] While adult human approximately weighs 70 kg and has a brain weigh about 1.7 kg [2% of the total body weight] 26

  27. Peripheral Nervous System - Network of nerves - Branch out of the central nervous system - Connect to other parts of the body - Regulates some voluntary and involuntary actions • Roles of Peripheral Nervous System • Peripheral nerves - 43 pairs of nerves 12 pairs: brain 31 pairs: spinal cord - Spaces between the vertebrate - One pair One nerve to the right, the other to the left - Divide into smaller branches - Top of the head - Tips of the fingers and toes Fun fact It’s estimated that if all the peripheral nerves in a body were joined end to end, they would circle the earth’s circumference 3 times. 27

  28. Peripheral Nervous System: Spinal Nerves - Contains sensory & motor neuron axons Sensory neurons - Dorsal nerve root - Body’s sense organs to the brain Motor neurons - Ventral nerve root - Brain to the body parts • Spinal nerve • Spinal nerve divisions Cervical nerves - Neck, shoulder, parts of arms Thoracic nerves - Front & back of chest, between ribs - Inside part of the arms Lumbar nerves - Part of the back, hips, front & side of both legs Sacral nerves - Groin, buttocks, back of legs & ankles Coccygeal nerves - Part of groin and buttocks 28

  29. Autonomic System vs. Somatic System • Autonomic & Somatic Systems • Autonomic system • Somatic system - Parts of brain, spinal cord, peripheral nerves - Controls involuntary actions Actions that happen subconsciously - Maintains homeostasis Ex. heart rate, blood pressure, temperature, glucose level - “Fight vs. Flight” reactions Ex. Increase in hearth rate, breathing, tensing of muscles - Controls voluntary actions Actions directed with self-conscious Ex. typing, raising hands, turning off television 29

  30. Reflexes • Reflex • Importance of reflexes - Automatic, instinctual movement - Assist development & survival Ex. Jerking your hand away from a hot stove 30

  31. Pupillary Light Reflex • Keeps out excessive light • External Links Pupillary Light Reflex Animation http://library.med.utah.edu/kw/hyperbrain/anim/reflex.html Pupillary Light Reflex Demonstration http://video.google.co.kr/videosearch?hl=ko&rlz=1T4GGLL_en&um=1&newwindow=1&q=pupillary%20reflex&ie=UTF-8&sa=N&tab=wv# 31

  32. Patellar Reflex (Knee-jerk) • What’s happening? • Purpose of Patellar Reflex • External Link - 50 milliseconds - Stretching of thigh muscle - Transmits message to the spain cord - Impulse is sent back - Falling reflex Off balanced Help recover our footing - Lose your balance from an upright position - Slack patellar tendon - Quadriceps contract Patellar Reflex Animation http://www.edumedia-sciences.com/en/a496-patellar-reflex 32

  33. Autonomic System: Sympathetic vs. Parasympathetic • Sympathetic & Parasympathetic Systems • Sympathetic system • Parasympathetic system - Nerve pathways Two sets of nerve impulses from the hypothalamus - Often control same body parts Opposite ways - During stress & action Speed up & increase activities Ex. increasing heart rate - During stress & action Slow down & decrease activities Ex. decreasing heart rate 33

  34. Nervous System Interactions • Nervous System vs. Other Body Systems 34

  35. Skeletal System • Skeletal System Functions • Interaction - Framework of the body - Allows muscle contraction - Storing & release of minerals - Protection of internal organs - Production of blood cells Skeletal System - Protects the brain & spinal cord - Informs body position to the brain Nervous System - The brain controls the muscles 35

  36. Muscular System • Muscular System Functions • Interactions - Enables internal & external organs’ movements - Maintains body temperature Muscular System - Informs body position & movements Nervous System - Controls skeletal muscle contraction 36

  37. Cardiovascular System • Cardiovascular System Functions • Interactions - Delivers oxygen, hormones, nutrients - Removes waste products Cardiovascular System - Maintains the blood-brain barrier - Send impulses about blood pressure to the brain Nervous System - The brain regulates heart rate & blood pressure 37

  38. Respiratory System • Respiratory System Functions • Interactions - Supplies oxygen - Removes carbon dioxide Nervous System - Regulates respiratory volume & blood gas levels - Monitors respiratory rate 38

  39. Endocrine System • Endocrine System Functions • Interactions - Releases hormones - Regulates metabolism, growth - Checks mineral & water balance - Responds to stress Endocrine System Functions - Affect brain’s neural processing & development Nervous System - Controls the pituitary gland & other endocrine glands 39

  40. Lymphatic System • Lymphatic System Functions • Interaction - Protection from infection Nervous System - Activates defense mechanisms 40

  41. Digestive System • Digestive System Functions • Interactions - Digests food - Distributes nutrients - Eliminates waste & absorbs water Digestive System - Building blocks of certain neurotransmitters - Sends sensory messages to the brain Nervous System - Controls digestive tract - Controls eating and drinking - Controls digestive muscles 41

  42. Reproductive System • Reproductive System Functions • Interactions - Releases hormones - Releases sperm & egg - Produces new life (growth of baby) Reproductive System - Affect brain development & sexual behavior Nervous System - Decides the time in which hormones are to be released 42

  43. Urinary System • Urinary System Functions • Interactions - Eliminates waste products - Maintains water & chemical balance Urinary System - Sends sensory information to the brain Nervous System - Regulates urination 43

  44. Integumentary System • Integumentary System • Interactions - Reduces water loss - Responds to stimuli - Regulates body temperature - Protection of internal contents Integumentary System - Send sensory messages to the brain Nervous System - Monitors peripheral blood flow & sweat glands - Control muscles connected to hair folicles 44

  45. Neurological Disorders • Cruetzfeldt-Jakob Disease • Tourette Syndrome • Parkinson’s Disease • Alzheimer’s Disease 45

  46. Cruetzfeldt-Jakob Disease (CJD) • What is Cruetzfeldt-Jakob Disease? • Statistics - Extremely rare, deteriorating, rapid, fatal brain disorder - Sponge-like brain (holes) - Every year one person out of million people worldwide - United States 200 cases of CJD per year - Death rate 90% of the patients die within a year 46

  47. CJD: Causes • “Slow virus”/ another organism • Prion - Failed to isolate a virus/another organism - Is it a virus? - Characteristics unusual for a virus No genetic information in forms of nucleic acids - Difficult to kill the agent Long incubation period - Leading theory - Prion that also causes mad cow disease 47

  48. CJD: Types • Sporadic CJD • Hereditary CJD • Acquired CJD - 85% of CJD cases - No known/apparent risk factors - 5-10% of CJD cases - Family history of CJD - Genetic mutation related to CJD - Rare type of CJD - Transmitted Exposure to CJD infected brain/nervous tissue 48

  49. CJD: Symptoms • First appearance of symptoms • Physical symptoms • Mental symptoms - Appears later in life Age of 60 Early stages - Lack of muscle coordination - Visual disturbances Later stages - Involuntary movements & jerks (myoclonus) - Possible blindness - Weakness of appendages Early stages - Failing memory - Possible insomnia, depression, unusual sensations Later stages - Personality changes Impaired memory, judgement, thinking - Possible comma 49

  50. CJD: Diagnosis • Neurological examinations • Most accurate diagnosis • Possible CJD diagnostic test - No one specific CJD diagnostic test - Spinal tap - EEG (Electroencephalogram) Brain electrical patterns - CT (Computerized tomography) Symptoms of other causes (ex. brain tumor, stroke) - MRI (Magnetic resonance imaging) Brain deterioration patters - Brain biopsy: neurological surgery Extremely dangerous for the patient & surgeon - Brain autopsy: examination after death - Detection of protein markers in the spinal fluid 50

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