Human Body - Nervous System

  1. Nervous system
    a regulatory system that maintains homeostasis
  2. receptor
    responds to internal or external change called stimuli
  3. impulse
    message started by receptor
  4. effector
    tissue or organ that carries out command from the nervous system
  5. organs of the nervous system
    • 1. brain
    • 2. spinal cord
  6. How are organs in the nervous system divided?
    • 1. according to position (structure/anatomy)
    • 2. according to action (function/physiology)
  7. 2 divisions of the nervous system based on position
    • 1. central nervous system
    • 2. peripheral nervous system
  8. central nervous system
    • 1. central location
    • 2. brain and spinal cord
  9. peripheral nervous system
    • 1. peripheral location
    • 2. 12 pairs of cranial nerves
    • 3. 31 pairs of spinal nerves
  10. cranial nerves
    • 1. carry impulses to and from brain
    • 2. 12 pairs
  11. spinal nerves
    • 1. carry impulses to and from spinal cord
    • 2. 31 pairs
  12. 2 divisions of the nervous system according to action
    • 1. somatic nervous system
    • 2. autonomic nervous system
  13. somatic nervous system
    • 1. voluntary
    • 2. effectors are voluntary skeletal muscle
  14. autonomic nervous system
    • 1. involuntary "automatic"
    • 2. no conscious control
    • 3. 2 divisions
  15. 2 divisions of the autonomic nervous system
    • 1. sympathetic nervous system
    • 2. parasympathetic nervous system
  16. sympathetic nervous system
    • 1. accelerates body in response to stress
    • 2. "fight or flight"
    • 3. "adrenergic" (activated by release of adrenaline)
  17. What are symptoms of the sympathetic nervous system reacting
    • 1. dilates pupils
    • 2. dilates bronchi
    • 3. accelerates heart
    • 4. stimulates release of livers store of glucose
    • 5. inhibits GI
    • 6. inhibits urinary
    • 7. dilates blood vessels in skeletal muscle
  18. parasympathetic nervous system
    • 1. reverses fight or flight after stress by releasing acetylcholine
    • 2. "rest and digest"
    • 3. conserves energy
    • 4. "cholinergic" (activated by acetylcholine)
  19. what are symptoms of the parasympathetic nervous system reacting?
    • 1. constricts pupils
    • 2. constricts bronchi
    • 3. slows heart
    • 4. stimulates GI
    • 5. stimulates urinary
    • 6. constricts blood vessels in skeletal muscle
    • 7. stimulates salivation, lacrimation, urination, digestion, defecation
  20. two types of nerve cells in nerve tissue
    • 1. neurons
    • 2. neuroglia "glia" cells
  21. Neurons
    • 1. nervous cell that can transmit impulse
    • 2. found in CNS and PNS
    • 3. cannot reproduce when damaged
  22. two characteristics of a neuron
    • 1. irritability (ability to react when stimulated)
    • 2. conductivity (ability to transmit an impulse)
  23. Structure of a neuron (parts)
    • 1. cell body
    • 2. dendrites
    • 3. axon
  24. cell body
    main part that contains nucleus and organelles
  25. dendrites
    many, short, branched fibers extending from cell body that receive stimuli and carry message towards cell body; "receptors"
  26. axon
    single, long fiber extending from cell body that carries message away from cell body to another nearby neuron or effector
  27. structure of a neuron
    axon of neuron is covered with white, fatty material called myelin that insulates and protects it
  28. types of neurons
    • 1. sensory neuron
    • 2. motor neuron
    • 3. interneurons/association neurons
  29. sensory neuron
    (afferent) carries impulse from receptors towards CNS
  30. motor neuron
    (efferent) carries impulse away from CNS towards effectors
  31. interneurons/association neurons
    carries impulse from sensory neuron to motor neuron within CNS; "go between"
  32. schwann cells
    produce myelin in PNS
  33. myelin sheath in PNS
    • 1. outermost membrane on schwann cell forms sleeve that allows damaged nerves in PNS to regrow and repair within it
    • 2. gaps exist between adjacent schwann cells called nodes of ranvier where no myelin is present
  34. oligodendrocytes
    produce myelin in CNS
  35. neuroglia cells
    • 1. nervous cell that protects, nourishes, and supports
    • 2. do not transmit impulses
    • 3. found in CNS and PNS
  36. 5 types of neuroglia cells
    • 1. astrocyte
    • 2. microglia
    • 3. oligodendrocytes
    • 4. schwann cell
    • 5. ependymal cell
  37. astrocyte
    • 1. large, star-shaped neuroglial
    • 2. located between neurons and blood vessels
    • 3. hold neurons and blood vessels near each other
    • 4. "blood-brain barrier"
  38. microglia
    • 1. small neuroglial cell that becomes phagocytic when pathogens invade nervous system or when there is degeneration
    • 2. support function of neuron
    • 3. removes harmful debris
  39. oligodendrocyte
    • 1. neuroglial cell that holds nerve fibers together
    • 2. produces myelin for cells in CNS
  40. schwann cell
    neuroglial cell that produces myelin for cells in PNS
  41. ependymal cell
    • 1. neuroglial cell that lines spaces in brain called ventricles and central canal of spinal cord
    • 2. produce cerebrospinal fluid
  42. Nerve tissue
    • 1. white matter
    • 2. gray matter
  43. white matter
    myelinated axons found in brain, spinal cord, and nerve trunks throughout the body
  44. gray matter
    fibers and cell bodies that are not myelinated
  45. nerve
    • 1. bundle in PNS
    • 2. PNS is made up of cranial nerves and spinal nerves
  46. tract
    • 1. bundle in CNS
    • 2. tracts are located in brain and spinal cord where they transmit impulses to and from brain
  47. nerves and tracts composed of:
    • 1. individual fiber and surrounding endoneurium
    • 2. fascicle (many fibers) and surround perineurium
    • 3. whole nerve or tract (many fascicles) and surrounding epineurium
  48. sensory/afferent nerves
    nerve contains only sensory neuron fibers that conduct impulses to brain in ascending tracts
  49. motor/efferent nerves
    nerve contains only motor neuron fibers that conduct impulses away from brain in descending tracts
  50. mixed nerve
    nerve contains both sensory and motor neuron fibers capable of conducting impulses in both directions (most cranial nerves and all spinal nerves)
  51. Polarization
    • 1. at rest, potassium inside and sodium outside cell
    • 2. at rest, inside is negative compared with outside
    • 3. neuron carries electrical charge called potential that is maintained by charged particles
  52. Depolarization
    • 1. sodium gates open allowing sodium to rush inward by diffusion when stimulated
    • 2. this temporary reversal causes inside of membrane to become positive
  53. Repolarization
    • 1. potassium channels open allowing it to leave the cell
    • 2. cell uses active transport to move sodium and potassium back to their original concentrations
  54. Neurotransmitters
    released from pre-synaptic cell at junction called synapse
  55. 3 best known transmitters
    • 1. epinephrine (adrenaline)
    • 2. norepinephrine (noradrenaline)
    • 3. acetylcholine
  56. epinephrine
    (adrenaline) released by adrenal gland
  57. acytelycholine
    • 1. released from neuron
    • 2. in PNS, regulates skeletal, smooth, and cardiac muscle
    • 3. in CNS, believed to be involved in learning, memory, and mood
  58. dopamine
    brain; Parkinson's disease
  59. serotonin
    • 1. brain
    • 2. mood and sleep; depression
  60. histamine
    • 1. tissues
    • 2. vasoconstricts bronchial smooth tissue
    • 3. vasodilates small blood vessels causing a drop in BP
  61. endorphins/enkephalins
    • 1. brain
    • 2. morphine-like effect
    • 3. "exercise high"
  62. neurotransmitters leave synapse by:
    • 1. diffusing back into pre-synaptic neuron to be reused (reuptake)
    • 2. diffusing slowly away from synapse
    • 3. being deactivated by enzymes
  63. spinal cord
    • 1. structure that allows communication between nerves (PNS) and brain (CNS)
    • 2. 18 inches long
    • 3. ascending and descending tracts
    • 4. irregular, inner area of gray matter surrounded by white matter
  64. reflex arc
    • 1. complete pathway through nervous system from stimuli to response
    • 2. total process from sensation to reaction
    • 3. sensory impulse enters spinal cord at dorsal horn
    • 4. sensory impulse travels upwards towards brain in ascending tracts
    • 5. motor impulse leaves spinal cord at ventral horn
  65. receptor
    (dendrite, specialized receptor cell, or special sense organ) detects stimuli and starts impulse
  66. effector
    (muscle or gland) carries out response
  67. simple reflex
    • 1. rapid, simple, automatic response that involves only a few neurons
    • 2. specific and predictable response to given stimuli
    • 3. eye blinks to avoids something coming towards it
    • 4. can be tested to check nervous system
  68. spinal reflex
    • passes through spinal cord only
    • example is stretch reflex
  69. spinal nerves
    • 31 pairs
    • all mixed nerves
    • attached to spinal cord by 2 roots
    • numbered by location
    • leave spinal cord through opening in vertebrae
  70. 2 roots where spinal nerves attach to spinal cord
    • 1. ventral root (motor)
    • 2. dorsal root (sensory)
  71. cervical plexus
    • supplies motor impulses to neck muscles and receives sensory impulses from neck and back of head
    • includes phrenic nerve
  72. brachial plexus
    • nerve supply to shoulder, arm, forearm, wrist, and hand
    • includes radial nerve
  73. lumbosacral plexus
    • nerve supply to legs and pelvis
    • includes sciatic nerve
  74. dermatomes
    • sensory neurons all over body on skin (except face and scalp) that send information through spinal cord to CNS on spinal nerves
    • "referred pain"
  75. brain
    • soft nervous tissue
    • made of billions of neurons
    • in cranial cavity
    • protected by membranes (meninges), fluid (CSF), and bone (skull)
  76. four parts of the brain that function together
    • 1. cerebrum
    • 2. diencephalon
    • 3. cerebellum
    • 4. brain stem
  77. meninges
    three layers of connective tissue that cover brain and spinal cord
  78. cerebral spinal fluid
    • clear liquid that circulates in and around brain and spinal cord
    • shock absorber
    • provides nutrients to nerve cells and removes their waste products
  79. ventricles
    • four hollow cavities
    • two lateral ventricles in each cerebral hemisphere
    • pia matter lining each ventricle provides vascular network call choroid plexis
  80. three layers of meninges
    • 1. dura matter
    • 2. arachnoid
    • 3. pia matter
  81. dura matter
    outermost layer attached to skull
  82. arachnoid
    • middle layer
    • space between arachnoid and pia matter
  83. pia matter
    • innermost layer attached to brain and spinal cord
    • blood supply (nutrients and oxygen)
  84. choroid plexus
    produces CSF by filtrating blood and releasing additional seretions
  85. cerebrum
    • largest, uppermost part of brain
    • outer layer of gray matter called cerebral cortex and inner area made of white matter
    • divided into right and left sides
  86. cerebral cortex is responsible for:
    • voluntary movement
    • conscious thought, memory, reasoning, abstract thinking
  87. longitudinal fissure
    divides cerebrum into right and left hemispheres
  88. corpus callosum
    connects hemispheres and allows impulses to pass from one side of the brain to the other
  89. gyri (gyrus)
    elevations on surface of cerebral cortex
  90. sulci (sulcus)
    shallow grooves between gyri on surface of cerebral cortex
  91. central sulcus
    between frontal and parietal lobes positioned at right angle to longitudinal fissure
  92. lateral sulcus
    curves alongside of each hemisphere separating temporal lobes from frontal and parietal lobes
  93. Four visible lobes of each hemisphere:
    • 1. frontal
    • 2. parietal
    • 3. temporal
    • 4. occipital
  94. Frontal lobe
    • anterior to central sulcus and superior to lateral sulcus
    • contains primary motor area which provides conscious control of voluntary skeletal muscle
    • contains motor speech area for spoken and written communication
  95. parietal lobe
    • posterior to central sulcus and superior to lateral sulcus
    • contains primary sensory area that receives and interprets nerve impulses
    • ability to estimate distance, size, and shape
  96. temporal lobe
    • inferior to lateral sulcus, folding under hemisphere on each side
    • contains auditory area for receiving and interpreting impulses from ear
    • contains olfactory area
  97. auditory receiving area
    detects sound from environment
  98. auditory association area
    interprets sound
  99. speech comprehension area
    (Wernicke area) functions in speech comprehension
  100. olfactory area
    interprets smell "olfaction" from receptors in nose
  101. occipital lobe
    • posterior to parietal lobe, extending over cerebellum
    • contains visual area for interpreting impulses that come from retina of eye
  102. electroencephalography (EEG)
    • recording of electrical activity of cerebral cortex
    • electrodes placed on head to record electrical activity, amplify it, and produce brain waves
    • used to diagnose sleep disorders, tumors, epilepsy, brain death
  103. electromyography (EMG)
    • test that measures electrical signals in muscles at rest during contraction to assess nerve damage
    • needle electrode inserted in muscle to record muscle's action potential
  104. nerve conduction velocity (NCV)
    • test that measures how fast an impulse travels through a nerve
    • nerve is stimulated
    • electrodes record nerve's action potential
  105. lumbar puncture
    needle inserted between 3rd and 4th vertebrae
  106. paralysis
    • description: loss of motor and sensory function
    • etiology: spinal cord, nerve, or brain injury
    • types based on disability
    • s&s: varies by degree
    • diagnosis: neurological assessment, MRI, CT
  107. paresis
    partial paralysis or weakness
  108. quadriplegia
    all four extremities and trunk
  109. paraplegia
    lower extremities
  110. hemiplegia
    one side/half of body (stroke)
  111. Herniated Disk
    • description: inner material of intervertebral disk protrude outward towards spinal cord
    • etiology: spinal trauma, strain
    • s&s: vary by location, back pain, numbness
    • diagnosis: spinal xray, MRI, CT, myelography
    • treatment: rest, PT, NSAIDs, analgesics
  112. Peripheal Neuritis
    • description: degeneration of nerves
    • etiology: nerve damage, trauma, infection (chicken pix, ticks), toxins (lead, arsenic)
    • s&s: pain, numbness, tingling, loss of sensation, muscular weakness
    • diagnosis: NCV, EMG
    • treatment: supportive; elimination of causative factors of possible
  113. Herpes Zoster (shingles)
    • description: viral infection along course of nerve that causes painful rash
    • etiology: reactivation of chickenpox; commonly effects elderly
    • s&s: unilateral pain, tingling, or burning
    • diagnosis: clinical
    • treatment: antivirals (acyclovir, famciclovir, valacyclovir)
    • prognosis: usually lasts a few weeks; does not reoccur, but pain may persist
  114. Bell's Palsy
    • description: inflammation or compression of seventh cranial nerve
    • etiology: may be viral (HSV, EBV)
    • s&s: facial weakness, drooping of mouth, pain in jaw, excessive tearing
    • diagnosis: clinical
    • treatment: antivirals, analgesics, corticosteroids
    • prognosis: good with spontaneous remission occurring within eight weeks
  115. Guillain-Barre Syndrome
    • description: acute, rapidly progressing autoimmune disorder (rare)
    • etiology: autoimmune, often follows viral infection
    • s&s: sudden onset of bilateral muscle weakness, numbness, and tingling
    • diagnosis: clinical, NCV, EMG
    • treatment: plamapheresis, mechanical ventilation
    • prognosis: most recover, but may have residual weakness indefinitely; can be fatal
  116. Spina Bifida
    • description: neural tube birth defect
    • etiology: genetic, lack of folic acid
    • diagnosis: prenatal (blood test), postnatal (clinical, MRI, ultrasound)
    • treatment: surgery; placement of shunt
    • prevention: folic acid supplement before and during pregnancy
  117. spina bifida occulta
    • mild; bones of spine do not close but meninges and spinal cord do not protrude; skin usually covers defect
    • hair/dimpling
  118. meningocele
    meninges protrude between vertebrae; requires surgery
  119. myelomeningocele
    • meninges and spinal cord protrude forming ssac
    • lack of bladder/bowel control
    • risk of infection
    • requires surgery
  120. hydrocephalus
    • description: CSF accumulates causing compression and swelling of brain
    • etiology: fetal infection, fetal development, bleeding in brain, head injury
    • s&s: abnormal increase in head diameter, tight scalp skin with prominent veins
    • diagnosis: in utero - ultrasound, after birth - clincial
    • treatment: placement of shunt
  121. Meningitis
    • description: inflammation of meninges
    • etiology: viral (more common) or bacterial (less common)
    • s&s: severe headache, fever, seizures, vomiting
    • diagnosis: evaluation of CSF
    • treatment: antivirals or hospitalization
    • prognosis: can be fatal especially in infants or elderly
    • prevention: vaccination
  122. Encephalitis
    • description: inflammation and swelling of brain
    • etiology: viral (more common) or bacterial (less common)
    • s&s: severe headache, fever, lethargy
    • diagnosis: EEG, MRI, lumbar puncture
    • treatment: antivirals, hospitalization, anti-convulsants, corticosteroids
    • prognosis: can be fatal especially infants or elderly
    • prevention: vaccination (MMR, varicella), use of insect repellant
  123. Cerebrovascular Accident
    • description: sudden altered blood flow to the brain (stroke)
    • etiology:80% ischemic, head injury, HTN
    • risk factors: family history, HTN, smoking, diabetes
    • s&s: sudden weakness, numbness, paralysis
    • diagnosis: clinical, confirmed with neurological assessment, MRI, CT
    • treatment: stat iv ischemic thrombolytic
    • prognosis: depends upon extent of damage and how soon treatment was received
  124. Transient Ischemic Attack
    • temporary, often recurrent episodes of impaired neurological function; mini strokes
    • usually last about 5 minutes
    • warning of possible CVA
  125. Alzheimer's Disease
    • description: chronic, progressive, brain deterioration where neurons in the cerebral cortex die and are replaced with plaques
    • affects mainly older people; most common cause of dementia in those over 60
    • etiology: unknown
    • s&s: early-loss of short term memory, disorientation, personality changes. later-incontinence, emotional detachment. last stage-severe deterioration of abilities
    • treatment: no cure; progression is slowed
  126. Parkinson's Disease
    • description: progressive condition resulting from a dopamine deficiency
    • etiology: unknown;more common in men
    • s&s: tremors, slowing of motion, muscle rigidity, impaired balance/speech
    • diagnosis: lab tests to check dopamine levels
    • treatment: levodopa/carbidopa
  127. Brain Tumors
    • description: mass of abnormal cells in brain tissue. (benign-slower growing, easier to remove/malignant-faster growing, harder to treat/primary-less common, occurs mainly in children/secondary-metastasis)
    • s&s: occurs when tumor grows enough to compress or crowd brain tissue
    • diagnosis: neurogical assessment, MRI, CT
    • treatment: surgery, radiation, chemo
    • prognosis: varies by type
  128. Amyotrophic Lateral Sclerosis (ALS) - Lou Gehrigs Disease
    • description: progressive, neuromuscular disease causing death of motor neurons
    • etiology: idiopathic; rarely genetic
    • s&s: subtle initially; weakness, twitching, clumsiness, difficulty breathing
    • diagnosis: affects men more; EMG, NCV
    • treatment: no cure; muscle relaxants
    • prognosis: terminal; usually respiratory failure
  129. Multiple Sclerosis (MS)
    • description: progressive neuromuscular disease affecting CNS
    • etiology: autoimmune; antibodies destroy myelin sheath which slows or blocks nerve signals
    • s&s: fatigue, problems with walking/balance/coordination
    • diagnosis: affects women more, MRI
    • treatment: immunomodulator medications, corticosteroids, muscle relaxants
    • prognosis: varies; average survival 35 years after diagnosis
Card Set
Human Body - Nervous System
human body, nervous system note cards