86 – The Brain and Mind – 6 Mark Question Practice A. Neurones are specialised cells transmitting nerve impulses. There are two types of neurones; Sensory cells, which send impulses from the receptor to the central processing centre and the motor neurones, transmit impulses from the brain and spinal cord to the effector cell that will respond to the stimulus. Impulses flow along thin tubes of cytoplasm.
In the sensory neurones, the cell body is located in the middle and two tubes come out of it; one from the dendrites at one end, which eceive impulses from the receptor cell, to the cell body, called the Dendron, and another from the axon terminals at the other end, which make connections with other neurones and pass the information to the CNS, to the cell body called the axon. In the motor neurones the cell body is located at the end and there isn’t a Dendron tube.
The Dendron and axons are covered in a fatty yellowish substance called the myelin which insulates them, stops impulses from flowing to other neurones and also peeds up the transmission of impulses. When neurones are stimulated they transmit an electrical impulse. Neurones transmit electrical impulses through the polarization inside the membrane of a neurone. This is a model answer for a 6 mark question in a Science GCSE exam. You differentiate between the two neurones if you like, and then describe the structures of the neurones and explain what each part of the neurone does, e. g what the myelin sheath does and so on.