PHYS Discriminative Somatic Senses Flashcards
3 types of exteroception.
• Mechanoreception – pressure/touch
• Thermoreception – temperature
• Nocireception – noxious (damaging/potentially damaging stimuli).
Classify rate of activity of mechanoreceptors based on location - deep vs sperficial.
Deep -> more rapidly acting than -> superficial.
Classify duration of action of rapid vs slow acting mechanoreceptors.
Rapid - signals at start & end of deformation
Slow - signals for the duration of the stimulus.
Relationship between receptor field size and perception.
Large RF = tuned to changes in vibration/pressure
Small RF = tuned to changes/perception of fine touch.
Speed of Meissner’s corpuscle.
Rapidly acting (RA I)
Receptor field size of Meissner’s corpscles
Small
Stimuli detected by Meissner’s corpuscles
Movement of light touch/low frequency vibrations over skin [responds best to constantly changing stimuli]
Location of Meissner’s corpuscles
Top of dermis (of non-hairy skin, fingertips & lips).
Speed of Ruffini’s end-organ mechanoreceptors.
Slow adapting.
Receptor field size of Ruffini’s end-organ mechanoreceptors.
Large (responsive to stretch).
Stimuli detected by Ruffini’s end-organ mechanoreceptors.
Stretch in joints & skin.
Location of Ruffini’s end-organ mechanoreceptors.
Mid-dermis (of both hairy & non-hairy skin).
Speed of Merkel’s discs/cells
Slow adapting (SA I)
Receptor field size of Merkel’s discs/cells.
Small.
Stimuli detected by Merkel’s discs/cells.
Low frequency vibration, indentation & texture [responds best to static stimuli].
Location of Merkel’s discs/cells.
Non-hairy skin at top of dermis (with high density in the fingertips).
Speed of Pacinian corpuscles.
Rapidly adapting (RA II).
Receptor field size of Pacinian corpscles.
Large.
Stimuli detected by Pacinian corpuscles.
Differences in smooth/course textures, vibration & pressure.
Location of Pacinian corpuscle.
Deep dermis (of fingers, mammary glands & genitals).
Muscle spindles structure.
Intrafusal muscle fibres - type Ia and II sensory axons (w both rapidly adapting & slow adapting nerve endings present).
Muscle spindle stimuli detection & signalling.
Muscle stretch. Signal both static & dynamic elements of muscle stretch.
Golgi tendon organ structure.
Collagen fibres (encapsulated structures which are filled with fluid & run from muscle-tendon) - type Ib nerve fibres spread across their surface as spiral endings.
Golgi tendon organ stimulation
Nerve terminals are stretched by tendon stretch - signalling muscle force/tension & inhibits further muscle contraction.
