BMS 300 1st Edition Lecture 24 Outline of Last Lecture I. Role of inhibition in summation and synaptic integration -inhibitory neurotransmitters 1. GABA2. glycine -opening ligand-gated inotropic channels -generating the I.P.S.P1. increasing Cl- permeability 2. effect on membrane voltage through changes in membrane resistance/permeability effect on E.P.S.P amplitude V=IR3. effect on duration of E.P.S.P through effect on Rm T=RmCm II. Myatatic reflex arc -the patellar tendon tap 1. stretch receptors in quads2. 1o sensory afferent 3. synapse on the lower motor neuron 4. effect on muscles 5. role of inhibition on spinal cord These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Outline of Current Lecture III. The myotatic reflex arc -reciprocal inhibition 1. inhibition of the antagonistic muscle>branch of the sensory afferent synapses inhibition interneuron 2. inhibition of LMN -reflex arc confined to the spinal cord -severing spinal cord leaves reflex 1. intact but disrupts ascending (sensory) and descending (motor) path 3 IV. Delivering somato sensory information to the brain -DCML (dorsicolumn medial meniscus)1. descrimitive touch 2. proproprioception (where our body is in space) V. Anterolateral system -spinothalamic >crude touch, temperature, pain VI. The three neuron chain -1o sensory afferent -2nd order- crosses the midline -3rd order- in the thalamus: projects to the sensory cortexVII. Following the path -DEML-anterolateral -brown sequard syndrome Current LectureRecap from last lecture -myotatic reflex arc: the one that came from the quads.-there are stretch activated -when we tug on the membrane we open stretch activated channels which innate a generator potential -the generator potential was a decrementing potential where its amplitude is proportional to the number of channels that opened -basically in the conductile region there were the v-gated sodium channels which would initiate action potential and the neuron would then propagate along the conductile region of the neuron primary sensory afferent: neuronal cell body -the neuronal cell body is found in a region known as the dorsal root ganglion>the ganglion is a collection of neuronal cell bodies in the PNS -there was a imaginary boundary which separated the inside and outside -we divided the spinal cord into two different regions >white matter (on the outside): myelination >grey matter (on the inside): neuronal cell bodies, input regions -we can then divide the spinal cord into two halves-the region above is dorsal (posterior)-the region below is ventral (anterior)-the primary sensory afferent synapse directly onto a lower motor neuron and then the neuron then sent a process out to the muscles -the region that was carrying both sensory and motor information in the PNS -a nerve is a collection of conductile regions in the PNS-this is called the EPSP*muscles are organized in antagonistic pairs -so that the quads have an antagonistic pair called the hamstring -when you strike the patellar tendon the quads are an extensor and the hamstrings are aflexor -when the quads shorten the hamstring resets it and vice versa -when the quads are active you turn off the hamstring and vice versa -there’s a “branch” that is called the inhibitory interneuron which will set up EPSP that form action potentials with an output region that synapses on a lower motor neuron which theninnervates the hamstrings aka “turning them off” ***Reciprocal innervationCross Section of the spinal cord -dorsal=sensory -ventral=motory-the region outside of the “butterfly” are white matter and conductile regionsmylinated-bilaterally symmetrical -dorsal root ganglia: collection of neuronal cell bodies in the periphery region -whatever you see on the left you see on the right and this happens throughout the CNS-not very far outside the CNS the ventral and dorsal roots merge into a spinal nerve -nerve: collection of neuronal conductile processes in the peripheral nervous system -following a primary sensory afferent -one of the important things is how we are segmented, like in the brainstem there is a part with 12 cranial nerves -nucleus: collection of neuronal cell bodies in the
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