The Somatosensory System (Touch) by Andrea, Katie, Kaitlynd, and Christian

The Sense of Touch

Initial Deductions

Although our initial deductions of the sense of touch were not incorrect, neither were they flushed out or with strong basis. We believed the sense of touch to be the result of a relation between nerves and the brain, which although true, is involved in a more complex system then we had previously thought. The relation between the nerves, receptors, somatic pathway and the brain was where we chose to focus our investigation.

The Somatosensory system 

The somatosensory system comprises the somatic system, or in colloquial terms, touch. It is formed from the skin, skeletal muscles, organs, cardiovascular system and bones. The skin plays the largest role in the somatic system, namely the dermis which is the bottom layer of skin where small nerve endings relay information to the spinal system (nervous) and then to the brain. Heat, cold, pain and pressure are the most common of the twenty nerve endings, or receptors, in our dermis.

The information gathered from the receptors is relayed via sensory nerves and it is known as the somatosensory pathway. It is comprised of two long neuron pathways with three major points. The first is the dorsal root ganglion located at the base of the spine. The transmission then reaches the brainstem and the root of the thalamus. The last point for the somatosensory pathway transmission is located in the postcentral gyrus of the parietal lobe (end of the thalamus gland).Locations in the brain are associated with each receptor, and as such the distinguishment of pain, pressure, heat, cold, etc are finalized in the brain.

Interesting facts

• The middle back is the least sensitive
• Most sensitive areas: hands, lip, face, neck, tongue, fingers, feet
• You shiver to warm up
• 100 touch receptors in each fingertip
• Young animals that have been touched more: grow faster, develop stronger immune   responses, more playful, less fear, tolerate stress better, greater resistance to physical harm
• Children that have been cradled or held more: gain weight, grow faster, start crawling, walking and grabbing earlier, more alert and active and sleep more soundly, develop stronger immune systems and have high IQ’s

Resources

• http://whalonlab.msu.edu/Student_Webpages/Babies/The%20Sense%20of%20Touch.htm
• http://library.thinkquest.org/3750/touch/touch.html
• http://en.wikipedia.org/wiki/Touch