Neurocytology Flashcards
where do the first order neurons of the dorsal column pathway synapse ?
dorsal column nuclei of the medulla
what type of information is carried by the sensory axons of the first order neurons of the dorsal column pathway?
sensory information regarding light, touch, proprioception and point discrimination
how many dorsal nuclei are in the medulla ?
two
what are the the names of the two dorsal column nuclei in the medulla ?
Nucleus Gracilis and Nucleus Cuneatus
what does the nucleus gracilis transmit ?
sensory information from the lower limbs and trunk
what does the nucleus cuneatus transmit ?
sensory information from the upper limbs and upper body but not the head
where do the the 2nd order neurons of the dorsal column pathway decussate
in the medulla
where do the 3rd order neurons of the dorsal column pathway lie ?
in the thalamus
what is in the name of nuclei in the thalamus? The 2nd order neurons synapse at this nuclei
ventral posterior lateral nucleus
where do the 3rd order neurons project and synapse ?
the 3rd order neurons ascend and synapse at the primary somatosensory cortex
why is the substantia gelatinosa important ?
it is where pain circuitry lies
what characterises the the sensory neuron in the substantia gelatinosa ? which neurons synapse with these neurons ?
they are small neurons. sensory neurones of the spinothalmic tract and dorsal column pathway synapse with these neurons in the substantia gelatinosa. unmyleinated C fibres carrying information about pain may also synapse with small sensory neurons of the substantia gelatinosa.
what does the central canal carry inside of it ?
it is directly connected to the 4th ventricle of the midbrain, so it must contain cerebrospinal fluid
where is the motor cortex ?
thin layer of neurons in the pre central gyrus
what is stained by the nissl stain ?
stains nucleic acids purple. dendrites are stained but not axons or synaptic terminals
