Grade 12 biology - The nervous system

Glial cell

A non conducting cell that is important for the structural support and metabolism of nerve cells

Myelin sheath

An insulated covering over the axon of a nerve cell

Node of ranvier

A regularly occurring gap between sections of myelin sheath along the axon

Central nervous system (CNS)

The body’s coordinating centre for mechanical and chemical actions; made up of the brain and spinal cord

Peripheral nervous system (PNS)

All parts of the nervous system, excluding the brain and spinal cord; relays information between the central nervous system and other parts of the body

Afferent system

The component of the peripheral nervous system that receives input through receptors and transmits the input to the central nervous system

Efferent system

The component of the peripheral nervous system that carries signals away to the effectors (muscles and glands)