ANAT 321 Lecture Notes - Lecture 3: David Ragsdale, Receptive Field, Hair Cell

• School: McGill University
• Department: Anatomy and Cell Biology
• Course: ANAT 321
• Professor: David Ragsdale

Document Summary

Sub-modalities are subdivision of the senses which are carried to the cns in different pathways (ex: heat and vibrations: represented by specialized fibers carrying out different functions. The combined activation of many receptors at once allows our brain to perceive composite sensations, such as something being wet, or the texture of a surface. Brain interprets relative activation of labelled lines and assigns a sensation to it. Axons propagate action potentials at different rates based on their anatomical differences. 4 main classes of somatic afferents: a , a , a , c: Low threshold mechanoreceptors (ruffini, merkel, meissner, pacinian) Slowest due to no myelination and small diameter. Receptive field: the area of skin surface where stimulation causes an increase of action potential rate of. Ex: the receptive fields on fingers are very small and two-point discrimination occurs when the stimuli are around 1-2 mm apart.