Sensory Basics
A change in the internal or external environment that the body can detect
What is a stimulus?
Pacinian corpuscles, Ruffini endings and Meissner's corpuscles are touch and pressure receptors found in this organ
What is the skin?
This membrane is commonly called the eardrum
What is the tympanic membrane?
Synthesized from vitamin A, this pigment absorbs light energy in the photoreceptors of all animals
What is retinal?
The five basic tastes are sweet, sour, salty, bitter and this savory one
What is umami?
The region in which a sensory receptor responds to a stimulus
What is a receptive field?
These mechanoreceptors help the CNS maintain balance and monitor the position of the head and limbs
What are proprioceptors?
The "stirrup" is the common name for this middle ear bone, which fits against the oval window
What is the stapes?
These individual faceted visual units make up the compound eye of insects and crustaceans
What are ommatidia?
In humans, taste buds are embedded in these outgrowths of the tongue
What are papillae?
The conversion of a stimulus into a graded receptor potential
What is sensory transduction?
Bundles of specialized muscle cells wrapped with afferent dendrites detect muscle length with these structures
What are muscle spindles?
Pitch depends on this property of a sound wave, measured in hertz
What is frequency?
Cones are concentrated in this small region of the retina where the lens centers the image
What is the fovea?
In insects, taste receptors sit inside these hollow sensory bristles
What are sensilla?
When a stimulus stays constant, the frequency of action potentials drops. This is the name of that process
What is sensory adaptation?
This fluid fills the semicircular canals, utricle and saccule
What is endolymph?
This duct connects the middle ear to the throat and equalizes pressure on the eardrum
What is the Eustachian (auditory) tube?
In the dark, rods steadily release this neurotransmitter
What is glutamate?
These are the only receptor cells that make direct connections with interneurons in the brain
What are olfactory receptors?
Stimulus intensity is registered by action potential frequency and by this second factor
What is the number and types of afferent neurons activated?
These calcium carbonate crystals embedded in the otolithic membrane lag behind when the head tilts, bending the sensory hairs
What are otoliths?
Located in the cochlear duct, this "spiral organ" contains the sensory hair cells that detect sound vibrations
What is the organ of Corti?
Horizontal cells sharpen edges and enhance contrast through this process
What is lateral inhibition?
Male silkworm moths can detect pheromones at a concentration of one molecule per this many air molecules
What is 10¹⁷?