A&P test 6

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A&P test 6
2010-07-14 18:22:55
Nervous tissue test

test 6: nervous tissue & spinal
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  1. Which systems control homeostasis?
    Endocrine and Nervous
  2. Nervous system
    bodys principle control and integrating system. Endocrine is similar, but less important.
  3. Sensory
    detecting changes inside and outside the body.
  4. integrative
    Interpreting the changes detected by the sensory mechanisms
  5. Motor
    Reacting to the changes through the action of organ systems such as glands and muscles.
  6. 2 major divisions in the breakdown of nervous system?
    • Central nervous system (CNS)
    • Peripheral nervous system (PNS)
  7. Central nervous system (CNS) consists of?
    • Spinal cord
    • Brain
  8. PNS consists of?
    • Cranial nerves
    • Spinal Nerves
  9. CNS is divided into?
    • Afferent/ascending/sensory-nerve cells that conduct impulses toward the brain.
    • Efferent/descending/motor- impulses from the brain to muscles and glands.
  10. Afferent and efferent system can be subdivided into?
    • Somatic Nervous System (SNS)
    • Autonomic Nervous System (ANS)
  11. SNS?
    Neurons that conduct impulses to the skeletal muscles only.
  12. ANS
    Nervous tissues that convey impulses from the brain.
  13. ANS conveys impulses from brain to:
    • Smooth Muscles
    • Cardiac muscles
    • glands
  14. ANS divided into
    • Sympathetic division- increases an organs activity.
    • Parasympathetic division- decreases an organs activity.
  15. Two types of nerve cells
    • Neurons
    • Neuroglia (glial cells)
  16. Neurons
    cells that conduct nerve impulses.
  17. Neuroglia
    cells that support and protect neurons.

    5 main types: Oligodendrocytes, astrocytes, neurolemmocytes, microglia, ependymal cells
  18. Oligodendrocytes
    form a supporting network for the individual neurons.
  19. Astrocyes
    attach to blood vessels forming a blood-brain barrier BBB that prevents harmful substances from reaching the brain.
  20. Neurolemmocytes (schwann cells)
    produce the myelin sheath that surrounds many nerve fibers.
  21. microglia
    engage in phagocytosis
  22. Ependymal cells
    Produce the cerebrospinal fluid of the CNS.
  23. Parts of the neuron
    • Cell body (soma)- contains a well defined, single nucleus within the nucleus of a granular cytoplasm
    • Dendrites- pick up and convey nerve impulses to soma.
    • Axon- conducts impulses from the neuron to the dendrites of another neuron or an affector organ
  24. what does the white color of the periferal nerve come from?
  25. Gray matter
    Unmyelinated nerves
  26. What increases the speed of a nerve impulse?
  27. What is comprised of almost exclusively of myelinated nerve fibers?
    The PNS
  28. Incapable of regeneration? (Nerve fibers)
  29. Nodes of Ranvier (neurofibriril nodes)
    gaps in the myelin sheath between the schwann cells
  30. axon terminals
    fine filaments that the axon terminates at.
  31. axon terminals terminate in
    synaptic end bulbs
  32. multiple dendrites and 1 axon?
    multipolar neurons
  33. 1 dendrite and 1 axon
    bipolar neurons
  34. 1 process extending from the cell body with a central branch (axon) and a peripheral branch (dendrite)
    unipolar neurons
  35. interneurons
    • purkinje cell- numerous dendritic fibers
    • pyramidal cell- body is shaped like a pyramid
  36. nerves
    bundles of neurons outside the spinal cord
  37. fiber tracts
    neurons inside the CNS
  38. resting nonconducting neuron
    • +charged outside and - charged inside
    • Polarized
  39. What maintains the positive and negative balance of a neuron?
    Sodium potassium pump
  40. outside of resting neuron is positive and inside is negative
    • resting membrane potential.
    • polarized
  41. occurs when the inside of the nerve becomes positive and the outside becomes negative
  42. when the channels close after the impulse has passd and the sodium is pumped back out of the nerve fiber.
  43. the period of time during which the membrane recovers and cannot initiate another action potential is?
    absolute refractory period
  44. If a stimulus is strong enough to generate action potential it will maintain constant ___ and max ___
    • speed
    • strength
  45. a stronger stimulus will/will not cause a greater impulse?
    will not
  46. continuous conduction
    • occurs only in unmyelinated
    • slower
  47. saltatory conduction
    • occurs only in myelinated fibers
    • slower
  48. why is saltatory conduction faster? Besides being myelinated.
    because it skips the schwann cells and goes from node of ranvier to the next
  49. fibers with a greater diameter conduct faster/slower?
    cold nerve fibers faster/slower?
    • faster
    • slower
  50. Electrical synapse
    • impuses pass from 1 cell to another using gap junctions.
    • 2 way transmissions
    • very rare, found in brain and cardiac muscle.
  51. Chemical synapse
    • Neuron secretes a chemical substance called a neurotransmitter that acts upon receptor sites of the next neuron.
    • 1 way direction, very common
  52. Synaptic vessicles
    packeges within the synaptic end bulb of the telodendria. They contain the neurotransmitter substance for conduction of the impulse.
  53. Space in each synapse?
    synaptic cleft
  54. The synaptic cleft is filled with extracellular fluid and separates the?
    synaptic end bulb of a neuron (pre-synaptic neuron) from the next (post synaptic neuron)
  55. Multiple Sclerosis
    scarring develop in the brain and spinal cord
  56. ____competes thith ACh for receptor ites and prevents muscular contractions?
  57. Bacteria that inhibits release of ACh to prevent muscle contraction.
    Botulism toxin
  58. inhibit synaptic conduction?
  59. Increase synaptic conductions?
  60. Substances are picked up periferally and taken back to the nerve cell body
    Axonial transport
  61. What protects the spinal cord?
    • vertebral bones
    • vertebral ligaments
    • ligamentum flavum
    • posterior longitudinal ligament
    • Cerebral spinal fluid
    • Meninges
  62. Where is the spinal cord located?
    Within the spinal canal of the vertebral column
  63. dura matter contains?
    • Epidural space- between the wall of vertebral canal and dura mater
    • subdural space- beneath the dura matter and contains serous fluid
  64. 3 coverings of the meninges
    • Dura mater- outer most
    • arachnoid mater- middle- contains CSF
    • pia mater - innermost- transparent and adheres to the brain/spinal cord
  65. What are the membraneous extensions of the Pia mater that suspend the spinal cord in the middle of the spinal canal?
    Denticulate ligaments
  66. Removal of CSF is called?
    Spinal tap, taken within the arachnoid space in the area of L4
  67. anesthesias introduced into the epidural space in the area of L2 is called?
    Epidural block- used for childbirth.
  68. Where does the spinal cord begin and end?
    • Brain
    • L1
  69. What are the 2 enlargements in the spinal cord and where are they?
    • Cervical-C4-T1
    • Lumbar-T9-T12
  70. What is the tapered portion of the spinal cord called?
    Conus Medullaris
  71. what originates at the L2 and ends at the Coccyx?
    Filum terminale
  72. Collection of nerves at the distal part of the spinal cord
    cauda equina
  73. Where are spinal taps performed?
    between L4 and L5
  74. spinal cord is divided into
    • anterior median fissure
    • posterior median sulcus
  75. outer portion of spinal cord?
    white matter called columns
  76. inner portion of spinal cord?
    Gray matter called horns
  77. Gray matter is in the shape of?
    Butterfly of capitol "H"
  78. The legs of the H are the?
    anterior gray horns, and posterior gray horns
  79. the middle of the H is
    Lateral gray horns
  80. the crossbar of the H is called the
    Gray commisure
  81. IN the middle of the gray commisure and runs the length of the spinal cord is the
    Central canal
  82. What is the myelinated fiber in the spinal cord called
    • columns
    • Anterior white
    • posterior white
    • lateral white
  83. ascendin/afferent/sensory tracts
    conduct sensory info to the brain
  84. descending/efferent/motor tracts
    conduct motor impulses from the brain outward
  85. Each pair of spinal nerves is connected to the spinal cord by?
    Nerve roots
  86. Dorsal nerver roots
    contain sensory nerve fibers only
  87. Ventral root
    contains motor axons only
  88. Enlarged portion of the dorsal root is called? what does it contain?
    • dorsal root ganglion
    • unipolar cell bodies of the sensory nerves
  89. ganglions
    collections of unmyelinated nerves that lie outside of the CNS
  90. Reflex
    a quick, involuntary response to a stimulus.
  91. Reflex Arc
    shortest route that can be taken by an impulse from a receptor to an effector.
  92. Receptor
    Dendrite that senses a change in the environment.
  93. sensory neuron
    passes the impulse to the end of the Axon
  94. integrating center
    place where association neurons inhibit, transmit, and reroute the impulse
  95. Motor neuron
    transmits an impulse to an effector organ for a response
  96. Effector
    a muscle or organ of the body that responds to a nerve impulse
  97. 2 basic types of reflexes
    monosynaptic and polysynaptic
  98. stretch reflex AKA___ is often called a ___because
    there is ___ synapse(s)
    • tendon jerk
    • monosynaptic reflex arc
    • 1
  99. the stretch reflex or tendon jerk or monosynaptic reflex arc involves.
    The response is generated by
    The stretch reflex controls
    It enters and exits ___ so it is ___
    • sensory and motor neurons only.
    • rapidly stretching a tendon or ligament
    • muscle length
    • on the same side, ipsilateral
  100. To test the ___ the patellar ligament is tapped with a percussion hammer
    The quad responds by
    This is monosynaptic/polysynaptic?
    • knee jerk reflex
    • extending the lower leg
    • monosynaptic
  101. polysynaptic reflex arc involves
    3 types:
    • sensory, association, and motor neurons
    • tendon reflex, flexor reflex, crossed extensor reflex
  102. tendon reflex is mono/poly?
    it operates as a ___ mechanism. its job is_________
    It involves what kind of neurons
    • polysynaptic
    • feedback
    • to protect muscles from damage due to excessive tension EX arm wrestling
    • motor neurons and inhibitory association neurons
  103. the tendon reflex is on the ___ side so is ___
    its sensors are called ___ are located in the tendons signal ______
    • same, ipsilateral
    • Golgi tendon organs
    • the muscle to relax if too much tension develops
  104. flexor reflex is poly/mono?
    it is a ___ reflex
    • polysynaptic
    • withdraw
  105. How does a flexor reflex work?
    A sensory neuron sends pain sensation to association neurons. Some ass.neurons stimulate flexor muscles and others inhibit extensor muscles so you can recoil from the pain.
  106. When a flexor reflex from a single sensory neuron causes association neurons to be affected at several levels of the spinal cord, the response is called an
    intersegmental reflex arc
  107. what occurs where the impulse crosses to the other side of the spinal cord and involves muscles on the opposite side of the body where both extremities are effected?
    crossed extensor reflex
  108. crossed extensor reflex is an example of ____ (impulse enters one side of SC and leaves the other)
    contralateral reflex arc
  109. superficial reflexes are ___ reflexes
    • withdraw
    • pin prick, ab reflex, cremasteric reflex, anal wink
  110. deep tendon reflexes involve ___ and are used for___
    • tendon stretch, testing the integrity of the reflex arcs
    • knee jerk, ankle jerk, Babinski sign
  111. How many of each
    cervical spinal nerves
    • 8 cervical
    • 12 thoracic
    • 5 lumbar
    • 5 sacral
    • 1 coccygeal
  112. spinal nerves are mixed bc they contain
    sensory and motor neurons
  113. entire nerve is covered by___
    bundles of nerves called__ is covered by __
    individual nerve fibers are covered by___
    • epineurium
    • fascicles, perineurium
    • endoneurium
  114. The part of the spinal cord that leaves the intervertebral foramen and divides into branches is called__
    The largest branch is__
    The dorsal aspect is __
    • rami
    • ventral ramus
    • dorsal ramus
  115. Rami networks are called
  116. innervates the skin, muscles of the head, neck and upper shoulders and the diaphram
    cervical plexus
  117. innervates most of the arm and many neck and shoulder muscles
    brachial plexus
  118. innervates the ab wall, pelvic area and muscles of the thighs. includes the femoral nerve
    lumbar plexus
  119. innervates the genitalia, butt and most of the lower extremities
    sacral plexus
  120. innervates the external genitalia
    pudendal nerve
  121. What nerve is sometimes blocked during childbirth (saddleblock)
    Why are they somethimes used?
    • pudendal anesthesia nerve blocks
    • much less general than epidural
  122. largest nerve of the sacral plexus and longest in the body
    it is formed from __ and __
    • sciatic
    • tibial and common peroneal
  123. what can be caused by damage to the sciatic nerve
    foot drop or tabes dorsalis
  124. all spinal nerves except c1 have sensory innervations in specific segments. these are called___.
    They can also help detect
    • dermatomes
    • which segment of the spinal cord has been damaged
  125. an acute infection of the periphrial nerves by herpes zoster
    chicken pox causes shingles
  126. spinal cord injuries are usually caused by__ or __
    trama or tumors
  127. spinal cord injuries termed:
    • monoplegia- paralysis of 1 extremity
    • paraplegia- both legs
    • hemiplegia- one side
    • quad
  128. severed peripherial nerves that have myelin sheaths can__ bc_
    reattach itself because myelin is capable of limited regenerative growth
  129. cutting the spinal cord in half results in
    loss of all sensations and motor control from the cut distally
  130. inflammation of the nerves
  131. neuritis of the sciatic nerve is