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30 Cards in this Set

  • Front
  • Back
Cauda equina
Lumbosacral nerve roots below the end of the spinal cord at L1-2
Conus medullaris
Tapering caudal-most part of the spinal cord at L1-2
Filum tereminale
Continuation of pia matter caudal to the end of the spinal cord
Lumbar cistern
Large collection of spinal fluid in subarachnoid space caudal to end of the spinal cord. Ends with caudal end of dural sac at S2.
Cervical/lumbar enlargement
Dilation of cervical and lumbosacral spinal cord due to large gray matter associated with limb function
The region of skin receiving sensory innervation by one dorsal root
The muscles receiving innervation by one ventral root
C.f. dermatome
Dorsal horn
Dorsal extension of spinal gray matter with sensory processing function
Ventral horn
Ventral extension of spinal gray matter with motor neurons
White matter of spinal cord; anterior, lateral or posterior to gray matter
Rexed’s lamina
Layers of spinal cord (I-IX from dorsal to ventral, with X around the central canal)
Intermediate gray
This is Rexed’s lamina VII. Contains mostly intererneurons
Motor pool
A motor pool is the collection of motor neurons to a single muscle
Motor unit
An alpha motor neuron and all of the muscle fibers innervated by it.
Alpha motor neuron
The large motor neurons that innervate extrafusal muscle fibers
Gamma motor neuron
The tiny motor neurons that innervate intrafusal muscle fibers.
Red (slow twitch; type I) muscle fiber
slow-fatigue, oxidatively active muscle fibers
White (fast twitch; type II) muscle fiber
rapid fatigue, high power and speed muscle fibers.
Size principle
The smallest motor neurons are activated before large ones in a gradually increasing (ramp) muscle contraction
The process of gradually increasing contraction, with activation of one motor unit first; gradual increase in frequency of firing of this motor unit; and addition of a second motor unit when the initial unit reaches a certain frequency.
Muscle fibers comprising the main contractile element of the muscle
Muscle fibers in the muscle spindle (part of a receptive organ for stretch)
Muscle spindle
sensory organ for muscle stretch. Comprised of intrafusal muscle fibers organized in parallel with extrafusal fibers.
Golgi tendon organ (GTO)
receptive element in tendon to perceive muscle tension
muscles that have similar action at a joint.
muscles that have opposite action at a joint
Resistance to passive movement that is higher with faster movements. This is due to over-activity of muscle stretch reflexes
Sudden loss of resistance to passive stretch due to activation of GTO
Physiological flexion
complex movement of withdrawal from noxious stimulation
Myotatic reflex
muscle stretch reflex. Contraction of stretched muscle and agonists, along with relaxation of antagonists