MARKET 1 Lecture Notes - Lecture 8: Microvillus, Phantom Pain, Olfactory Receptor
Document Summary
Introduction to psychology 2: cognitive and biological psychology. How is the physical stimulus converted into an electrical signal: sensory receptors have specialised dendrites that will open ion channels if stimulated by the appropriate external stimulus, for example, a feather rubs a hair on the skin. The dendrite of a touch receptor is wrapped around the hair so that when the hair moves the dendrite is stretched. This opens sodium channels on the dendrite causing depolarisation: a similar process occurs in other senses. For example, photoreceptors absorb light that causes a change in the shape of light sensitive pigments that ultimately result in ion channels opening. Pain and temperature are carried differently to touch and pressure. Pain is carried by unmyelinated axons, whereas other somatosensory neurons are myelinated. What is a receptive field: each sensory receptor is sensitive to physical stimuli that impinge on a circumscribed area of the body.
