Sensory A&P Flashcards
What conditions must be satisfied for sensation
(1) Stimulus – A change of environment that is capable of activating sensory neurons.
(2) Sensory Receptor – System that converts stimulus into electrical signal, which produces one or more nerve impulses if it is large enough.
(3) Impulse conduction – Conduction along a neural pathway from sensory receptor to the brain
(4) Impulse integration – a region of the brain receives the impulse and converts it into sensation.
(a) Interpretation of sensations is primarily the function of
the cerebral cortex.
most sensory receptors have the ability to adapt, this is that
decreases in strength during prolonged stimulation.
The simplest receptors are
free nerve endings
(lack structural specialization and can be seen under a light microscope)
d. Structural groups of receptors are
(1) Free nerve endings –Bare dendrites associated with pain, tickle, itch, and some touch sensation.
(2) Encapsulated nerve endings –dendrites enclosed in a capsulated connective tissue, for pressure, vibration and some touch.
(3) Separate Cell – receptor cell that synapses with first order neuron, in the eye (photoreceptors), inner ear, (hair cells), taste buds (gustatory cells).
e. Functional groups of receptors are
MNO TC
(1) Mechanoreceptors – detects pressure, provided sensation of touch, vibration, hearing, proprioception, equilibrium, and stretching of internal vessels and organs.
(2) Thermoreceptors – detects changes in temperature
(3) Nociceptors – responds to painful stimuli resulting physical change or tissue damage
(4) Photoreceptors – detect light that strikes the retina of the eye.
(5) Chemoreceptors – detect chemicals in the mouth (tastes), nose (smell) and body fluids
(6) Osmoreceptors – senses the osmotic pressure of body fluids.
(1) Tactile receptors location
throughout the various layers of skin
(2) Thermal receptors location
free nerve endings located throughout the body
