Body senses and perceptual plasticity Flashcards
What are the three main somatosenses?
Cutaneous sense, organic (internal) sense and vestibular (already covered)
What is cutaneous sense?
Sensitivity to stimuli that involve the skin.
E.g. pressure, vibration, heating/cooling, and events that cause tissue damage (pain).
What is organic internal sense?
A sense modality that arises from receptors located within the inner organs of the body.
What is proprioception?
Ability to sense position of the body and limbs.
What is vestibular?
Perception of the body’s balance.
What are the types of cutaneous receptors?
Free nerve endings, other specialised receptors.
What are free nerve endings?
Found in both hairy and non-hairy skin e.g. on the palms or soles of feet. In hairy skin they surround hair follicles.
What are the other specialised receptors that are cutaneous receptors?
Involved in the detection of mechanical stimuli such as stretch and vibrations, warmth/coolness and pain.
What is the heaviest organ in the body and what does it do?
Skin- protects the organism by keeping damaging agents from penetrating the body.
What is epidermis?
The outer layer of the skin which is made up of dead skin cells.
What is dermis?
Below the epidermis and contains mechanoreceptors that respond to stimuli such as pressure, stretching and vibrations.
What are the two types of mechanoreceptors?
Merkel receptor and Meissner corpuscle.
What are Merkel receptors?
Fires continuously while stimulus is presented, responsible for sensing fine details.
What are meissner corpuscles?
Fires only when a stimulus is first applied and when it is removed, responsible for controlling hand-grip.
What are the two other types of mechanoreceptors located deeper in the skin?
Ruffini cylinder and Pacinian corpuscle.
What are Ruffini cylinder receptors?
Fires continuous to stimulation, associated with perceiving stretching of the skin.
What is the pacinian corpuscle?
Fires only when stimulus is first applied and when it is removed, associated with sensing rapid vibrations.
What are the internal senses?
Sensory nerve endings located in our internal organs, bones and joints.
What are specialised receptors in the internal senses?
Include, muscle spindles that detect changes in muscle length and mechanoreceptors that respond to the movement and the angles of our joints.
What is the sum of all the sensations in the internal senses?
Proprioception.
How is tactile acuity achieved?
There is a high density of Merkel receptors in the fingertips, similar to cones in the fovea, results from both two-point thresholds and grating acuity studies are consistent with the density of Merkel receptors.
What do areas with more acuity have?
Larger areas of cortical tissue and smaller receptive fields on the skin,
