what is the difference between neurilemma and myelin sheath
Neurilemma The neurilemma is underlain by the myelin sheath (referred to as the medullary sheath in the included illustrations). In the central nervous system, axons are myelinated by oligodendrocytes, thus lack neurilemma. The myelin sheaths of Oligodendrocytes do not have neurilemma because excess cytoplasm is directed centrally toward the oligodendrocyte cell body.
Neuroglia Neuroglia, also called glial cells, or simply glia are non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the central and peripheral nervous systems.[1] In the central nervous system, glial cells include oligodendrocytes, astrocytes, ependymal cells and microglia, and in the peripheral nervous system glial cells include Schwann cells and satellite cells. The term derives from Greek γλία and γλοία "glue"; pronounced in English as either /ˈɡliːə/ or /ˈɡlaɪə/