Chapter 50

detection of a stimulus by sensory cells

the conversion of a physical o chemical stimulus to a change in the membrane potential of a sensory receptor

change in membrane potential; are graded, as in their magnitude varies with the strength of the stimulus

action potentials!

not so important; actions potentials have reached the brain and neurons process this input; constructs that don't exist outside of the brain

responsible for touch, hearing, pressure; sense physical deformation; bending of an external structure generates tension that alters the permeability of ion channels

responsible for smell & taste; can be general and transmit info about total solute concentration or specific and can respond to individual molecules

responsible for vision (rods and cones); absorb photons

detect heat and cold; located in skin and anterior hypothalamus; send signals to body's thermostat (hypothalamus)

naked dendrites that respond to noxious (harmful) stimuli and trigger defensive reactions

sensory organs that sense gravity and maintain equilibrium; common type consists of a layer of cilliated receptor cells surrounding a hollow chamber that contains statoliths (grains of sand)

a what, where and how much system

a what and how much system; not where not where NOT where

ONLY what; kind of how much; again NOT WHERE

insects and crustaceans; consists of up to several thousand light detectors called ommatidia each with it's own light focusing lense; very effective @ detecting movement/color

works like a camera; light enters through pupil and amount let it is determined by the iris which either dilates or contracts; lens behind all this moves either forward or back to focus

spherical; flat

light absorbing molecule found in photoreceptors (is bound to an opsin)

visual pigment found in rods; made up of retinal & a certain opsin; bleaching = when it absorbs light one bond in the retinal goes from cis to trans (bent to straight) and this causes a destabilization/activation