Types of neurons , structure & Functions

A neuron is a specialized cell with a cell body containing nucleus, and extending from cell body two types of cytoplasmic processes: one or more dendrites, and a single axon. The dendrites, and the entire cell body surface, are the nerve cell’s receptive apparatus. Some of these inputs are excitatory, others inhabitory. In vertebrates and some complex invertebrates, the axon is covered with an insulating sheath of myelin. Neurons may assume many shapes, depending on their function and locations. The three functional types of neurons are:

(a) Sensory (receptor or afferent) neurons, which either act as receptors of stimuli themselves or are activated by receptors to which these are connected.

(b) Motor (Efferent or effector) neurons –Which send the information (processed in CNS or PNS) via a signal (impulse) to the body’s effectors. Causing them to respond by contracting, and glands by secreting.

(c) Interneuron’s or associative neurons, -Which are neither sensory nor motor but connect neurons with other neurons.

Afferent and efferent neurons lie mostly outside the brain and nerve cord (CNS) while interneurons lie entirely within the CNS While interneurons lie entirely within the CNS and make up 99% of all neutrons in the body. Fig 2.1


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neuron-types

Figure 2.1

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