Nerve fibers are sensitive. Sensory (sensory) neurons are also called afferent (excitatory) neurons because they are excited in response to stimulation of sensory (afferent) nerve endings.
Sensory nerve fiber - the process of a neuron that perceives irritation, is the terminal part of the sensory nerve, along which excitation is transmitted to the central part of the nervous system. In receptors, sensitivity is limited by the length and diameter of the axon. The length of the nerve pathways under all conditions is limited by the distance between the place of perception of the external stimulus and the central end of the sensory fibers to its synapses. Synapses are scattered along the entire length of sensory neurons until they terminate on excitatory neurons in various structures of the brain or spinal cord. Nerve sensitivity fibers are capable of transmitting only excitatory impulses. When received, these signals can provide processes aimed at understanding the surrounding world, relationships with other individuals, or participating in muscle movements. Consequently, nervous sensitivity acts as an organ of movement and cognition.
Neurons are characterized by high lability, i.e. the ability to quickly change their state of excitation or inhibition. One neuron has up to 40 thousand nerve hairs, which end the nerve cells. Sense organs are associated with these endings - the organs of vision, hearing, taste, smell, as well as supporting and skeletal muscles. Sensation and perception arise when corresponding stimuli cause a local effect on a nerve cell; under the influence of irritation the level of excitability changes. This determines the appearance of sensations. The ability to sense sensations is associated with the simultaneous excitation of many nerve cells.