The fingertips are good at touch discrimination, but the torso is not. For example, the cornea is several hundred times more sensitive to painful stimuli than are the soles of the feet. These varying responses are based largely on the number and distribution of receptors. Larger areas of the cortex are devoted to sensations from the hands and lips much smaller cortical regions represent less sensitive parts of the body.ĭifferent parts of the body vary in their sensitivity to tactile and painful stimuli. The transmission of this information is highly topographic, meaning that the body is represented in an orderly fashion at different levels of the nervous system. Signals from touch receptors pass via sensory nerves to the spinal cord, where they synapse, or make contact with, other nerve cells, which in turn send the information to the thalamus and sensory cortex. They can be triggered by the slightest movement of the hairs. The nerve endings are remarkably sensitive.
Sensitive nerve endings skin#
In hairy skin areas, some receptors consist of webs of sensory nerve cell endings wrapped around the base of hairs.
We do this through touch receptors in the skin. This descending pathway sends messages to the spinal cord where it suppresses the transmission of tissue damage signals to the higher brain centers. These messages can be suppressed by a system of neurons that originates in the midbrain. From the spinal cord, the impulses are carried to the brainstem, thalamus, and cerebral cortex and ultimately perceived as pain. Pain messages are picked up by receptors and transmitted to the spinal cord via small myelinated fibers and very small unmyelinated fibers.
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