BIOL 3402 Lecture Notes - Lecture 9: Nerve Growth Factor, Ependyma, Schwann Cell
Document Summary
Neuroglia: (glial cell) 1 trillion neurons in the nervous system but neuroglia out number neurons by 10:1 ration. Prevents neurons from touching each other and gives precision to pathways. Oligodendrocytes: form myelin sheaths that speed signal conduction. Ependymal cells: lines the brain and secrete cerebrospinal fluid. Microglia: wander through the cns looking for debris and damage, develop with white blood cells and concentrate in areas of damage. Diverse functions include framework for nerves, connect to capillaries, convert glucose to lactate, secrete nerve growth factors, when the nerve is damaged the astrocyte hardens forming sclerosis. Schwann cells: produce myelin sheath by winding around the nerve and helping with regeneration. Satellite cell: provide electrical insulation around soma and regulate chemical environment of neurons. *** myelin sheath starts developing at week 14 of development and ends during adolescence. Neurilemma: thick outermost coil of myelin sheath which contains the nucleus, and basil lamina is external to this.
