BSCI 201 Lecture Notes - Lecture 29: Schwann Cell, Ependyma, Axolemma

• School: University of Maryland
• Department: Biological Sciences Program
• Course: BSCI 201
• Professor: Justicia Opoku

Document Summary

4 in the cns: astrocytes, microglia, ependymal cells, oligodendrocytes. Use the cytoplasmic extensions to wrap around segments of axons to myelinate axons. One oligodendrocytes can myelinate axons of several neurons. 2 in the pns: satellite cells form halo around ganglia (collection of neuron cell bodies)- surround ganglia. Control and regulate the chemical environment around ganglia: schwann cells (neurolemmocytes) Analogous structures have the same function as each other. Homologous structures derived from the same embryonic region. Myeltation of axons by an oligodendrocytes neurilemmal is absent: function of myelination. Physical protection of the axolemma (plasma membrane of an axon) Electrical insulation myelin sheath prevent inference from neighboring axons during impulse transmission. Myelinated axons in the pns or the cns have areas devoid of myelin sheath called nodes of randier. During impulse (electrical) transmission because myelin sheath inhibits generations of electrical signals, these electrical signals can be generated at the nodes of randier. Hence, the transmission appears to jumps from node to node.