Neurilemma
The Schwann cells wrap themselves tightly around the axon like a jellyroll. During the wrapping process, the cytoplasm is squeezed from between adjacent layers of the Schwann cell membranes, so that when the process is completed a tight core of plasma membrane material encompasses the axon. This wrapping is the myelin sheath. The Schwann cell nucleus and the bulk of its cytoplasm end up just beneath the outermost portion of its plasma membrane. This peripheral part of the Schwann cell and its exposed plasma membrane is the neurilemma.
Surrounding the myelin sheath, there is a thin membrane called neurilemmal sheath. This is also called neurilemma or sheath of Schwann. This contains Schwann cells, which have flattened and elongated nuclei. The cytoplasm is thin and modified to form the thin sheath of neurilemma enclosing the myelin sheath. One nucleus is present in each internode of the axon. The nucleus is situated between myelin sheath adn neurilemma. At the node of Ranvier (where myelin sheath is absent), the neurilemma invaginates and runs up to axolemma in the form of a finger like process. In nonmyelinated nerve fiber, the neurilemma continuously surrounds axolemma. Neurilemma is absent in central nervous system. Neurilemma is necessary for the formation of myelin sheath (myelinogeneis).
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Schwann cells are glia that myelinate the neurons of the Peripheral Nervous System
Myelin Sheath Cytoplasm Dendrites Cell Body
Schwann cells make the myelin sheath that encloses some axons
When the peripheral nervous system develops, Schwann cells line up along unmyelinated axons at regular intervals that eventually become the nodes of Ranvier (important for saltatory nerve condution). The ensheathing process takes place as Schwann cells wrap around the axon many times over, creating concentric layers whose cytoplasm progressively condenses. Contact with the axons also activates myelin genes leading to the expression of myelin glycoproteins and lipids across the Schwann cell plasma membrane. The sheath therefore consists of plasma membrane, cytosol, lipids, glycoproteins, and the Schwann cell nucleus.*So basically, the schwann cells is a protective membrane that covers the axon. It also produces myelin sheath (the coating of a neuron), which increases the speed of the nerve impulse.
Theodor Schwann was a German physiologist who co-founded the cell theory. He discovered that all animals are made up of cells, which led to the understanding that cells are the basic unit of life. Schwann also identified the role of enzymes in digestion.
The three major components of a eukaryotic cell are - true membrane bound nucleus membrane bound organelles like endoplasmic reticulum, mitochondria, golgi apparatus cytoskeleton
Cellular life invented Theodor Schwann. Theodore Schwann then discovered cellular life.
interesting facts about thedor schwann
Theodor Schwann was a German zoologist.