Page 100 - 84 human physiolofy part-1

Chapter 5

Layers of the skin, showing the Merkel's Cell. (GFDL - Crystal Mason)
Ruffini corpuscles

Ruffini corpuscles are Thermoreceptors, aiding in the detection of temperature changes. Named
after Angelo Ruffini, the Ruffini ending is a class of slowly adapting mechanoreceptor thought to exist
only in the glabrous dermis and subcutaneous tissue of humans. This spindle-shaped receptor is
sensitive to skin stretch, and contributes to the kinesthetic sense of and control of finger position and
movement.

Disorders of Touch

Sensory Processing Disorder
In most people sensory integration occurs naturally without a thought process. But in some
people the sensory integration does not develop properly and becomes distorted. In these people,
the brain and central nervous system misinterprets everyday sensory information such as touch,
sound and movement. Research is still being done on this disorder but they are finding direct
links to SPD with other disorders like ADD/ADHD, premature birth, Autism, Down’s Syndrome
and Fragile X.
Tactile defensiveness
Considered a category of SPD, tactile defensiveness is an overreaction to the sense of touch.
Identified by Dr. Jean Ayers in the 1960’s. A person with tactile defensiveness will react with a
“flight or fight” reaction to touch stimuli that a normal person would interpret as harmless. Most
cases are noticed in children or babies due to the fact that they do not want to be touched or
cuddled as a normal child would. A child with this disorder will probably have these sign or
symptoms:

• Does not like to go barefoot or have feet touched

100 | Human Physiology