TOUCH

Smital Patel

Alexa Paganini

Nathan Penn

Period 3

TOUCH SENSORY STRUCTURES

Free Nerve Endings: free ends extend between epithelial cells; associated with sensations of touch and pressure

Meissner’s Corpuscles: small, flattened masses of connective tissue cells; respond to the motion of objects that barely contact the skin by interpreting impulses

Pacinian Corpuscles: large structures composed of connective tissue fibers and cells; respond to heavy pressure

TOUCH SENSORY STRUCTURES

TYPES OF RECEPTORSTypes of Receptors Stimulated by…

Chemoreceptors Changes in chemical concentration of

substances

Pain Receptors Tissue damage

Thermoreceptors Changes in temperature

Machanoreceptor Changes in pressure or movement

Photoreceptors Light energy

PATHWAY OF SENSORY INFORMATION

Receptors are distributed throughout the skin and internal tissues, except for that of the brain.

When stimulated, receptors send impulses to the central nervous system.

These impulses are processed in the gray matter of the spinal cord before they ascend to the brain.

Within the brain, impulses pass through the reticular formation before being conducted to the cerebral cortex.

The cerebral cortex then interprets the source of the impulses and determines how to react.

DIAGRAM OF PATHWAY

DISORDERS

Giaccai type acroosteolysis AKA Hereditary Sensory Neuropathy, Type 2 (HSN2): Rare genetic disorder that usually

begins in childhood.Loss of feeling, especially in the

hands and feet.Loss of sensation often leads to

neglect of wounds.Could result in amputation in

extreme cases.

DISORDERS

Tactile Agnosia: Subtle and nondisabling disorder.Results from lesions, tumors, or

damage to the mesial temporal, relosplenial, or mesial occipital cortices of the brain.

Causes an individual to be unable to recognize objects by touch.

However, other senses can be used to identify objects without difficulty.