3.5: Somatosensory

Somatosensory System

Responsible for the human sense of touch (somatic)

Touch

The first sense the body develops

Skin

The largest and most complex organ in the somatosensory system

Mechanoreception

Sense of pressure

Thermoreceptor

Sense of hear

Nociception

Sense of pain

Cutaneous Receptors

Receptors of the skin that tell the body about the three main subdivisions (pressure, temperature, pain)

Proprioceptors

Receptor cells in the muscles and joints (kinesthesia)

Speed

The ___ of adaption refers to how quickly the receptor will react to a stimulus and how long that reaction will be sustained after the stimulus is removed

Receptive field size

The amount of skin area that responds to the stimulus, with smaller regions specializing in locating stimuli accurately.

First Pain/Cutaneous pricking pain

First type is a rapidly transmitted signal with a high spatial resolution.

It is easy go locate and easy to tolerate.

Second pain/Burning pain

The second type is slower and highly effective.

It is more difficult to locate and not as easy to tolerate.

Deep pain

Third type, arising from visceral, musculature, and joints.

Challenging to tolerate and intolerable and chronic.

Somatic System Disorder

Formerly known as Somatoform Disorder, it is a psychological disorder related to the somatosensory system.

Conversion disorder

It involves an actual loss of bodily function

Example: blindness, paralysis, numbness

Illness anxiety disorder

It involves persistent and excessive worry about developing a severe illness.

Body dysmorphic disorder

Concerned with body image

Pain Disorder

Chronic pain experienced in one or more areas thought to be caused by psychological stress.

Vestibular System

Together with the cochlea, it provides sense of balance

Semicircular Canal System

Indicates rotational movements

Otoliths

Indicate linear accelerations

Vestibulo-ocular reflex

The process wherein signals from the vestibular system are sent to the neural structures that control eye movements and provide clear vision.