Lecture 6 02/16/2014
Glial cellskind of cells in the nervous system
Subtypes; different glia do different things ▯they have a structural role, metabolic role, blood/brain barrier.
Blood/brain barriertoxins are excluded from leaking out into the brainglia cells act as a filter around
capillaries: protective mechanism that shields the brain.
Myelin wrapping around (forming layers of their membrane) around the axon.
Glia cells in CNSform myelin sheaths=oligodendrocytes
Physically support the axon
Development of where the axon goes
Prevents leakage across the membrane
PNSSchwann cells(glia cells)
What would happen if it didn’t work? If the myelin wasn’t sufficient? ▯congenital hypothyroidismtoo little
thyroid function. Occurs because of iodine deficiency in pregnant women. Iodine is necessary for thyroid
hormones; iodine is the vertebrate developmental hormone. Iodine deficiency: nervous system forming
without normal synapse connection=mental retardation (cretinism) not reversible unless recognized 6
weeks after birth.
Normal myelination, but lost during adulthood? Demyelinationloss of myelinautoimmune disease, the
immune system recognizes something about myelin and attack it. Multiple Sclerosis (chronic) and Guillain
Barre (acute inflammatory demyelinating polyneuropathy) peripheral NS Schwann cell disease (can
overcome this). Both diseases are independent of each other. These diseases can be acquired by: being
exposed to a foreign virus/bacteria and the immune system attacks it but some part of the foreign organism
is similar to myelin and the immune system recognizes that and attacks myelin as well. Wax/wane presence
of the disease. If you have one autoimmune disease, is it more likely you can acquire another? Yes.
Synapse Figure 6.27, Ca2+ triggers exocytosis; active zone, where vesicles are waiting at the docking site.
Voltage gated Ca2+ channels at th