BIOL 4380 Lecture Notes - Lecture 6: Dorsal Root Ganglion, Medulla Oblongata, Brainstem
13 May 2018
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Feb 8th,
Chapter 9 is ery dense and e an’t e responsile for all of it!
Central pathway conveying tactile information to the CNS
• Fig 9.8. Is a very very dense figure.
• We’re lookig at a few segets of the spial ord ad we’re lookig at ross setios i the
brainstem. Panel B refers to pathways that are facial.
• Brainstem: all of these structures are very different in other mammals, these are only human
brainstem segments. The first region is called medulla oblongata, next region is called pons,
then ascending tracts of cerebrum, then the lateral view of brainstem. Cerebellum is not a part
of the brainstem.
• Medial is towards the center, lateral is towards the periphery and sides.
• Afferents extending both to our skin, and into the spinal cord as well (from the dorsal root
ganglia), it splits up into 2 directions as it enter spinal cord: sensory afferent splits into 2
branches: one is going down (descending), one going up is ascending.
• The afferents that are going up, from the upper body and middle body regions, they form a tract
that’s alled the ueate trat. The oes that goes fro lower etreities are alled Graile
trat. The’re ot just oposed of asedig aons, also contain a second neuron that the
sesor euro sapses with. Ad together, the for a trat that’s goig up ad if the trat
origiates fro upper od → ueate.
• Note that this neuron that is innervated by the mechanosensory receptor neuron = first order
neuron, as the tracts are going upward and as they enter the medulla in the brainstem they
form additional synapses with another set of neurons: the second order neurons. This
innervation, the connection between 1st and 2nd order neurons is happening in gracile and
Cuneate. These are regions that concentrate neurons of a particular type.
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Document Summary
Chapter 9 is (cid:448)ery dense and (cid:449)e (cid:272)an"t (cid:271)e responsi(cid:271)le for all of it! Central pathway conveying tactile information to the cns. Is a very very dense figure: we"re looki(cid:374)g at a few seg(cid:373)e(cid:374)ts of the spi(cid:374)al (cid:272)ord a(cid:374)d we"re looki(cid:374)g at (cid:272)ross se(cid:272)tio(cid:374)s i(cid:374) the brainstem. Panel b refers to pathways that are facial: brainstem: all of these structures are very different in other mammals, these are only human brainstem segments. The first region is called medulla oblongata, next region is called pons, then ascending tracts of cerebrum, then the lateral view of brainstem. This innervation, the connection between 1st and 2nd order neurons is happening in gracile and. Because it is more in the center of the spinal cord vs the periphery. As these fibers ascend form their respective ganglia into the cns, as they synapse with 2nd order neurons, they rotate a little in a horizontal plain.
