Physio-Tactile and Position Senses (Brownell) Flashcards
What is mechanoreception?
Ability of a cell to sense its own shape and tension.
What are the 2 types of mechanoreceptors? What info do they report? What are they based on?
- Tonic receptors: slow adapting receptors that report amplitude and duration of stimulus.
- Phasic receptors: fast adapting receptors that are sensitive to changes in stimulus strength.
• Based on how fast they get back to the baseline and adjust.
What are the 5 types of somatic sensory afferents?
- Merkel’s disks
- Meissner corpuscle
- Pacinian corpuscle
- Ruffini’s corpuscles
- Hair follicle receptor
Merkel’s Disks: receptive field size? Location? Function? Adaptive speed? Stimuli?
- Small receptive field.
- Location: tip of epidermal sweat ridges.
- Function: form and texture perception.
- Slow adaptive receptor.
- Responds to fine/small stimuli.
- Good at braille.
Meissner corpuscle: receptive field size? Location? Function?
- Small receptive field.
- Location: glabrous skin.
- Motion detection (skin motion); grip control; low frequency vibrations.
Pacinian corpuscle: receptive field size? Location? Function?
- Large receptive field.
- Location: dermis and deeper tissues.
- Sense vibrations (extremely sensitive).
Ruffini’s corpuscles: receptive field size? Adaptive speed?Function?
- Large receptive field.
- Slow adapting.
- Sense skin stretch; hand shape.
What is a hair follicle receptor sensitive to?
Displacement sensitive.
What leads to impulse propagation in somatosensory neurons?
Mechanotransduction (senses stretch in membrane) → activate voltage-gated channels → impulse generation/propagation.
Describe Somatotopic plasticity following amputation.
Removal of sensory input stimulates the outgrowth and remodeling of adjacent cortical receptive fields.
Activity dependent mapping. Use it or lose it.
