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Neuro week 3- reflexes/voluntary motor
Anatomy
24
Medical
Graduate
10/15/2018

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Cards

Term
Cerebellar nuclei from medial to lateral?
Definition
Fastigial (F), Globose (G), Emboliform (E), Dentate (D)
Term
Dentate nuclei project ipsilaterally or contralaterally?
Definition
Contralaterally
Term
Fastigial nuclei project ipsilaterally or contralaterally?
Definition
Both
Term
What two cerebellar nuclei are grouped together as "interposed"?
Definition
Emboliform (E) and Globose (G)
Term
Dentate projection?
Definition
To thalamus, then to motor cortex
Term
What affect does dopamine have on D1 receptors?
Definition
Excitatory
Term
What affect does dopamine have on D2 receptors?
Definition
Inhibitory
Term
How can you distinguish medium spiny cells from the striatum that are involved in the Direct vs. the Indirect pathway?
Definition
Direct- Just GABA, D1 receptors
Indirect- GABA + Enkephalins, D2 receptors
Term
How is the gain of the muscle spindle regulated?
Definition
If both alpha and gamma MNs are activated, there is no decrease in the firing of Ia afferent neurons, even if muscle contracts
Term
What is muscle tone?
Definition
the normal degree of tension maintained in skeletal muscles
by involuntary spinal reflexes; the resistance of skeletal muscle to passive
elongation or stretch.
Term
Flexor reflex?
Definition
Flexor reflex = withdrawal reflex
A protective polysynaptic ipsilateral segmental reflex in which a painful stimulus
triggers the contraction of ipsilateral flexor muscles (and the ipsilateral
extensors are inhibited) which takes the limb away from the source of pain.
These reflexes have slower onset and longer response than the stretch
(extensor) reflexes.
Term
Two types of intrafusal fibers?
Definition
Nuclear bags
Nuclear chains
Term
Two types of muscle spindle sensory fiber endings?
Definition
Annulo-spiral (coils)
Flower spray
Term
Intersegmental reflex arc
Definition
a polysynaptic neuron pathway
which involves sensory impulses being received in one
segment of the spinal cord and then stimulating interneurons
which route the sensory information to motor neurons in both
the superior and inferior segments of the spinal cord in order
to permit innervation of a variety of muscles in the reflex
action
Term
Crossed extensor reflex
Definition
a polysynaptic contralateral
segmental reflex that is usually associated with the same
painful stimulus which triggered a flexor/withdrawal reflex; in
the crossed extensor reflex, the contralateral extensors
contract (and the ipsilateral flexors are inhibited) which tends
to adjust for any shift in the center of gravity so that balance is
maintained and body weight is properly supported
Term
Subcomponents of basal ganglia?
Definition
Caudate
Putamen
Globus pallidus
Subthalamic nucleus
Substantia nigra
(Some argue for Nucleus accumbens, ventral pallidum & amygdala)
Term
What type of interneurons are in the striatum?
Definition
Cholinergic giant cells
Term
What "detour" makes it the indirect pathway?
Definition
Globus pallidus external segment to subthalamic nucleus
Term
What type of cells project from the striatum to the GP?
Definition
Medium spiny cells
Term
Is substance P involved in the direct or indirect pathway?
Definition
Direct
Term
Is enkephalin involved in the direct or indirect pathway?
Definition
Indirect
Term
What is the underlying pathophysiology to Huntington's?
Definition
Idiopathic destruction of medium spiny cells of the striatum, preferentially those involved in the INDIRECT pathway --> lack of inhibition of movement
Term
Underlying pathophys of hemiballismus?
Definition
Subthalamic Nucleus lesion- damage to indirect pathway
Term
Underlying pathophys of Parkinson's?
Definition
Damage to dopaminergic cells of Substantia nigra pars compacta- damage to both direct & indirect pathways --> hyperkinetic (resting tremor) AND hypokinetic (slowness) symptoms
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