Sensation Lecture summary

This system (i.e. sensory sys.) is the part of the nervous system which detects, transmits and processes sensory information. Each individual system consists of sensory receptors (detection), neural pathways (transmission), and parts of the brain involved in sensory perception and processing.

Separate systems exist for vision, hearing, somatic sensation (touch and proprioception), taste (gustation) and smell (olfaction).

Different receptors are sensitive to separate types of sensory stimuli. Receptors send impulses in certain patterns to send information about the intensity of a stimulus (for example, how much pressure is being exerted). The location in the body of the sensory receptor that is stimulated (e.g. the tongue) goes to a particular area of the brain (e.g. the "tongue area") which gives the brain information about the location of the sensory stimulus.

Disturbances anywhere in the somatosensory (touch) pathway can lead to numbness or tingling . It is important to remember that a disturbance in joint position sensation (proprioception) can lead to disturbances in motor function and may actually be perceived as weakness or cause a movement disorder called pseudoathetosis in which the limb moves unintentionally due to a disturbance of its perceived position in space. A video showing a good example of pseudoathetosis can be seen here.

Carpal tunnnel syndrome is a well-known example of the sort of symptoms which may arise due to disturbances of the system of sensation , although it may also cause motor problems (weakness).

More study resources related to the sensory system can be found here