myelin sheath

the insulating layer around many axons that increases the speed of conduction of nerve impulses. It consists of myelin and is laid down by glia, which wrap themselves around adjacent axons. The myelin sheath is interrupted by small gaps, called nodes of Ranvier, which are spaced about every millimeter along the axon. Also called medullary sheath.

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Psychology term of the day

May 6th 2024

public residential facility

any residential setting directly operated by state or local government for individuals with intellectual or developmental disabilities. The term generally refers to large institutions, such as developmental centers (formerly called training schools or state schools), but the number of smaller residential settings, such as community residences, that are publicly operated now greatly exceeds the number of remaining large public facilities.