PSL300H1 Lecture Notes - Lecture 26: Lamellar Corpuscle, Dorsal Root Ganglion, Mechanoreceptor
Document Summary
Sense below the chin through the spinal cord: receptors in the dorsal root ganglion. Sense in the head : receptors cell bodies inside the brain. Transduction occurs in the nerve endings: surface of skin & viscera. Located at the bottom of the epidermis. Tonic signalling signal contact: for as long as the contact exists signalling exists. Stimulus: stroking motions, momentary pull (ie shear) In tongue & hairless skin: tongue, erogenous zones, palms, fingertips. Many looped / coiled (like a spring) nerve endings: egg-shaped. High numbers in children, but decreases with age. Stimuli: tiny & quick displacements vibration. Nerve endings in concentric layers (like an onion: many layers. High density = high acuity (resolution: palms, lips, fingertips. Resolution = 2 point discrimination: 2-4 mm high acuity, 40mm low acuity (calf) 2 types: cold receptor (maximal activation: 30 c, warm receptor (maximal activation: 45 c) Phasic-tonic receptors: relatively high levels of adaptation, but not fully.
