PNS Exam 1

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PNS Exam 1
2010-10-19 20:37:32
Life University

PNS Lecture
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  1. What are the 3 major components of the PNS?
    • 1. Cranial Nerves.
    • 2. Ganglia.
    • 3. Spinal Nerves.
  2. True or false: Nuclei are groups of cell bodies in the PNS.
    False. Ganglia are groups of cell bodies in the PNS.
  3. Dorsal root ganglia are associated with which type of cell?
    DRG = pseudounipolar.
  4. Endoneurium: surrounds one fiber.
    Perineurium: surrounds several fibers creating a fascicle.
    Epineurium: surrounds groups of fascicles.
  5. What is an a/k/a for rough ER?
    • Nissel bodies: synthesizes proteins.
    • The axon does not have Nissel Bodies, but dendrites can have Nissel bodies.
  6. Which part of the neuron contains chromosomes?
    • Nuclei:
    • Double layered membrane with phospholipids & pores.
    • Allows communication between inside & outside of nucleus via pores connecting to the ER.
  7. Name the 3 functions of Golgi Bodies.
    • 1. Storage.
    • 2. Glycoprotein formation.
    • 3. Lysosome/enzyme production.
  8. What is the main function of mitochondria?
    ATP (energy) production.
  9. What are the 2 main function of cytoskeleton?
    • 1. Forms the frame of the neuron.
    • 2. Aids in transport.

    • Microtubules: largest.
    • Microfilaments: smaller (10).
    • Microfibrils: smallest (3-7).
  10. True or false? Axons are completely covered in Nissel Bodies.
    • False: axons do not have any Nissel Bodies.
    • Axons conduct action potentials.
  11. Which process of a neuron is an extension of the cell body?
    • Dendrites.
    • Contains Nissel Bodies.
    • Can have large branches where as axons do not.
  12. True or false: larger axons conduct action potentials faster than smaller axons.
    • True!
    • Myelenated fibers conduct faster than unmyelenated fibers.
  13. The synaptic cleft allows for diffused neurotransmitters to attach where?
    • The post synaptic membrane.
    • The synaptic cleft has enzymes to break down NT's.
    • Anterograde: moving down the axon away from the cell body (soma).
    • Retrograde: moving back up the axon toward the cell body (soma).
  14. Histogenesis of neurons (from inside to outside):
    Ventricular zone.
    Intermediate zone.
    Marginal zone.
    • Ventricular zone: stem cell, pluripotent, begin development.
    • Intermediate zone: differentiates into neuroblasts or glialblasts.
    • Marginal zone: mature neurons.
  15. Which zone of histogenesis is determined, but still immature?
    The intermediate zone.
  16. Name the 6 microgilal cells.
    • 1. Astrocytes: injury response, mechanical & metabolic support.
    • 2. Oligodendrocytes: forms myelin in the CNS.
    • 3. Ependymal cells: CSF production.
    • 4. Microglia: phagocytosis (immunity of the CNS).
    • 5. Schwann cells: myelenation in the PNS, axonal regrowth, & metabolism.
    • 6. Satellite cells: flattened schwann cell, similar to astrocytes.
  17. Which migroglial cell is responsible for forming scar tissue in damaged brain areas?
  18. What is the number 1 type of brain cancer?
  19. What is the most common form of gliomas?
    • Astrocytomas.
    • Oligodendrogliomas: very rare.
  20. Which dermatome innervates the nipple?
    • T4.
    • T10: umbilicus.
    • L5: big toe.
    • S1: heel.
    • S2: back of thigh.
  21. What type of receptors respond to a stimulus?
    Sensory receptors.
  22. What is the name for the territory from which a sensory unit can be excited?
    • Receptive field.
    • Single neuron.
    • Responds to one sensory unit.
    • More sensitive areas are smaller.
  23. The transformation of a stimulus into an electical signal is described by what term?
    • Sensory transduction.
    • Discriminative touch & kinesthetic stimulation.
    • Carried by myelenated type A axons.
  24. True or false: myelenated type C axons are responsible for carrying pain, touch, & temperature sensations.
    False: unmyelenated type C axons are responsible for pain, touch, & temp sensations.
  25. Rapidly adapting responses are associated with which type of receptors?
    • Phasic.
    • Responds quickly & maximally.
    • Will stop responding even when the stimulus continues.
    • There is a refractory period before it will respond again.
    • ...bursting?!?!?
  26. Slowly adapting responses are assocated with which type of receptors?
    • Tonic.
    • Will continue to respons to a stimulus without a refractory period.
  27. Name the 3 types of non-encapsulated receptors.
    • 1. Free nerve endings: pain & temp.
    • 2. Follicular: touch.
    • 3. Merkel cells: pressure.
  28. Name the 3 types of encapsulated receptors.
    • 1. Meissner's: light touch, type A.
    • 2. Ruffini's: shearing (drag) forces.
    • 3. Pacinian: vibration.
  29. Mnemonic for remembering which receptors are slow adaptors: MR Slow.
    • Merkel cells (non-encapsulated).
    • Ruffini's.
    • Slow.

    Rapid = PMF.
  30. Reflexes are a predictable response to a stimulus which will happen every time.
    Sensory limb & motor limb.
  31. What is the term used to describe a stem fiber & all of its endings?
    Sensory unit.
  32. What is the functional unit of the motor system?
    The motor unit.
  33. Name at least 2 characteristics associated with extrafusal muscle fibers.
    • 1. Alpha neurons (via grey matter).
    • 2. Results in movement of skeletal muscles (motor unit).
    • 3. Gamma motor neuron -> muscle spindle.
    • 4. The more neurons that are involved, the more intricate the movement.

    Intrafusal (muscle spindles) = gamma motor neurons = proprioception.
  34. True or false: golgi tendon organs are found at the muscle-tendon junction.
  35. What are the 4 functions of golgi tendon organs?
    • 1. Measuring the force of contractions (strong or weak).
    • 2. Autogenic inhibition: self control of inhibition.
    • 3. Protecting muscles from excessive contraction.
    • 4. Fine adjustments in the force of muscle contractions.
  36. Freely ending unmyelenated nerve fibers are responsible for pain & excitatory reflexes. Where are they found?
    • 1. Ligaments.
    • 2. Capsules.
    • 3. Menisci.
  37. What is an a/k/a for the flexor reflex?
    • Withdrawal reflex.
    • Involves the whole limb.
    • Thus several spinal segments.
    • Has crossed effects: simultaneous & opposite pattern of activity in the contralateral limb.
  38. Which lobe integrates sensory information from joints, muscles, & skin?
    The parietal lobe.