Key Terms
Sensation
Activation of receptor cells at the stimulus site Perception: central processing of those signals into a meaningful patt
General sense
Distributed throughout the body; not associated with a dedicated organ; includes touch, pain, temperature, pressure, pro
Sensory modality
The way information is encoded for a specific type of stimulus Submodality: a more specific category within a major sens
Five recognized tastes
Sweet, salty, sour, bitter, umami Umami means savory; triggered by L-glutamate; found in protein-rich foods A possible s
Signal pathway
Olfactory neuron axons pass through the cribriform plate of the ethmoid bone, reach the olfactory bulb on the ventral fr
Anosmia
Loss of smell. Causes include blunt head trauma (shearing olfactory tract axons), certain antibiotics that destroy olfac
Sound transduction in the cochlea
1. Sound waves vibrate the tympanic membrane 2.
Utricle and saccule
Detect head position and linear acceleration
Semicircular canals
Three ring-like extensions of the vestibule; detect rotational movement
Pain and temperature
Transduced by free nerve endings
Eye support structures
Bony orbit, eyelids, palpebral conjunctiva (inner lid membrane), scleral conjunctiva, lacrimal gland (produces tears), l
Fovea
Exact center of the retina; no supporting cells or blood vessels; only photoreceptors; highest visual acuity; each photo
Rods
Sensitive to low light; contain rhodopsin; detect light at 498 nm; grayscale vision; one photon can trigger an action po
Phototransduction
1. Photon strikes retinal cofactor (a vitamin A derivative) inside an opsin molecule 2.
Spinal nerves
Mixed motor and sensory; sensory fibers enter via dorsal root; contralateral projection to brain (right body to left bra