Question | Answer |
Sensory receptor | any structure specialized to detect a stimulus |
transduction | the conversion of one energy to another |
Sensation | awareness of the stimulus |
Modality | the type of stimulus or the sensation it produces |
Location | encoded by which nerve fibers are sending signals to the brain |
Intensity | strength of stimuli based on which fibers are firing, and how fast those fibers are firing |
Duration | how long the stimulus lasts |
Classification of Receptors | -By stimulus modality
-by origin of stimulus |
Thermoreceptors | respond to heat and cold |
Photoreceptors | respond to light |
Nociceptors | respond to tissue injury |
Chemoreceptors | respond to chemicals |
Mechanoreceptors | respond to physical deformation of a cell |
Exteroreceptors | detect stimuli outside the body |
Interoceptors | detect stimuli in the internal organs |
Proprioceptors | detect the position and movements of the body |
Unencapsulated Nerve Endings | sensory dendrites that are not wrapped with CT |
Free nerve endings | detect pain, heat, cold |
Tactile discs | detect light touch and pressure |
Hair receptors | detect hair movement |
Encapsulated Nerve Endings | nerve fibers wrapped in glial cells or CT |
Tactile corpuscles | detect light touch and texture, in dermal papillae |
End bulbs | similar to tactile corpuscles but are found in mucous membranes of the lips and tongue, and conjunctiva |
Lamellar corpuscles | detect deep pressure, stretch, tickle, and vibration |
Bulbous corpuscles | detect heavy touch, pressure, and stretching of skin, and joint movement |
Nociceptors.. | ..occur in skin, mucosa, all organs except brain and liver |
Myelinated pain fibers produce fast pain | a feeling of sharp, localized pain perceived at the time of injury |
Unmyelinated pain fibers produce slow pain | longer-lasting, dull, diffuse feeling |
Injured tissues | release chemicals that stimulate the nociceptors and trigger pain |
Referred pain | pain in the viscera is mistakenly thought to come from skin |
Taste | Gustation |
Lingual papillae | surface protrusions on the tongue |
Filiform papillae | tiny spikes without taste buds that detect the texture of food |
Foliate papillae | parallel ridges on the sides of the tongue that lose most of the taste buds by age 2-3 |
Fungiform papillae | widely distributed, but concentrated at the tip and sides of the tongue |
Vallate papillae | papillae arranged in a V at the rear of the tongue |
Taste buds | groups of taste cells, supporting cells, and basal cells |
Taste cell | epithelial cell with taste hairs, which serve as receptors, and that release neurotransmitters at their base to stimulate sensory nerve fibers |
Basal cells | stem cells that multiply and replace taste cells |
Primary tastes | salty, sweet, sour, bitter, umame |
Smell | Olfaction |
Olfactory mucosa | a patch of olfactory cells, supporting cells, and basal stem cells in the roof of the nasal cavity |
Olfactory cells | neurons with olfactory hairs, cilia that have binding sites for odor molecules, on the modified dendrite |
The axons leave the nasal cavity through .. | ..the cribriform foramina and converge to become cranial nerve I |
An odorant molecule .. | .binds to a receptor on an olfactory hair |
Binding.. | ..activates a 2nd messenger system |
The cell depolarizes triggering .. | ..an action potential that transmits a signal to the brain |
The signal travels .. | ..to the orbitofrontal cortex which receives input from taste and smell and integrates them into our overall perception of flavor |
Outer ear | a funnel for conducting vibrations to the timpanic membrane |
Auricle (pinna) | fleshy structure on the side of the head |
Auditory canal | the passage leading through the temporal bone to the tympanic membrane |
Middle ear | located in tympanic cavity of the temporal bone |
Tympanic membrane | the membrane that closes the inner end of the auditory canal and vibrates free in response to the sound |
Auditory tube | a passageway from the middle ear to the nasopharynx that allows air to enter to equalize air pressure |
Auditory ossicles (malleus, incus, stapes) | bones that connect the tympanic membrane to the inner ear |
Oval window | opening covered by the stapes |
Inner Ear | passage ways in the temporal bone |
Vestibule | a chamber that contains organs of equilibrium |
Cochlea | a coiled tube that is the organ of hearing |
Scala vestibuli and scala tympani | chambers filled with perilymph that connect at the apex of the cochlea |
Cochlear duct | middle chamber of the cochlea formed by the vestibular membrane and basilar membrane |
Spiral organ | cells and membranes in the cochlear duct that convert vibrations into nerve impulse |
Hair cells | sensory cells with short projections called stereocilia |
Tectorial membrane | gelatinous layer resting on hair cells |
- sound | an audible vibration of molecules |
Transmission | air tympanic membrane ossicles perilymph vestibular membrane basilar membrane round window membrane |
The reverse for outward vibration ... | ..pushes the basilar membrane up and pushes the hair cells against the tectorial membrane |
On Inner Hair Cells is.. | ..a protein at its tip that functions as a gated ion channel |
If the basilar membrane rises, | the IHC push against the tectorial membrane bending the stereocilia and pulling open the gate |
K+ in the ______ flows through the gate and depolarizes the hair cells | endolymph |
The hair cells release .... | ...a neurotransmitter from the base which stimulates the dendrites of a sensory neuron of cochlear nerve |
Equilibrium | coordination, balance, and orientation in 3-D space |
Saccule and utricle | chambers in the vestibule of the inner ear |
Macula | hair cells and supporting cells in the saccule and utricle |
Otolithic membrane | gelatinous layer the stereocilia hair cells are embedded in |
When the head is tilted .. | ..the otolithic membrane sags and bend the stereocilia, stimulating the hair cells |
When you begin moving or stop.... | ..the otolithic membrane moves at a different speed than the rest of the tissue thus bending the stereocilia and stimulating a nerve signal to advise the brain of a change in velocity |
The Semicircular ducts | passageways filled with endolymph that detect rotational movements |
Crista ampullaris | hair cells and supporting cells in the ampulla |
Cupula | gelatinous cap the stereocilia are embedded in |
When the head turns.. | the duct rotates but the endolymph lags behind, pushing the cupula thus bending the stereocilia and stimulating the hair cells |
The hair cells synapse .. | ..at their bases with sensory fibers of the vestibular nerve |
Eyebrows | facial expressions and protect eyes from glare and sweat |
Eyelids | block foreign objects from the eye, blink to moisten eyes etc. |
Conjuctiva | transparent mucous membrane that covers the inner surface of the eyelid and the anterior surface of the eye except the cornea, which secretes mucous to prevent the eyeball from drying |
Lacrimal gland | gland at the superolateral corner of the orbit that produces tears |
Lacrimal punctum | pore on medial corner that collect tears lacrimal canal lacrimal sac nasolacrimal duct nasal cavity |
Extrinsic eye muscles | muscles attach to the walls of the orbit and the external surface of the eyeball that move the eye |
Fibrous layer | (tunic fibrosa) |
Sclera | white of the eye, of dense CT perforated by BV and nerves |
Cornea | anterior transparent region that admits light into the eye |
Vascular layer | (tunica vasculosa) |
Choroid | posterior, highly vascular, pigmented layer |
Ciliary body | muscular ring around the lens that supports the iris and lens and secretes aqueous humor |
Iris | Adjustable diaphragm that controls the diameter of the pupil |
Inner layer (tunica interna) | retina and the beginning of the optic nerve |
Optical Components | transparent elements that admit light rays |
Aqueous humor | serous fluid secreted by the ciliary body into the posterior chamber which flows though the pupil into the anterior chamber where it is reabsorbed by the sclera venous sinus |
Lens | transparent oval suspended behind the pupil by suspensory ligaments attached to the ciliary body |
Vitreous body | transparent jelly filling the space behind the lens |
Retina | transparent membrane attached to the back of the eye |
Macula lutea | center of the retina with the fovea centralis which produces the most finely detailed images |
Optic disc | where the optic nerves leave the rear of the eye and BV enter and exit the eye |
Blind spot | optic disc contain no receptor |
Pupillary constriction | smooth muscles stimulated by the PNS that narrow the pupil and admit less light into the eye |
Pupillary dilation | myoepithelial cells stimulated by the SNS that widen the pupil and admit more light into the eye |
Refraction | the bending of light rays |
Light that passes through the very center of the eye .. | ..is not bent |
Light that passes through at an angle.. | |
The refraction by the lens .. | ..fine-tunes the image |
The Near Response | adjustment to close-range vision |
Convergence of the eyes | orients the visual axis of each eye toward the object in order to focus the image on each fovea |
Constriction of the pupil | constriction decreases peripheral light rays so that refraction occurs closer to the better-focused center |
Accommodation of the lens | change in the curvature of the lens that enables you to focus on near objects |
Photoreceptor cells | absorb light and generate a signal |
rods | responsible for night vision |
Cones | responsible for day vision and color vision |
Bipolar cells | first-order neurons; synapse with rods and cones |
Ganglion cells | second-order neurons; axons form the optic nerve |
Horizontal cells and amacrine cells | form horizontal connection between rod, cone, and bipolar cells that enhance the perception of contrast, the edge of objects and changes in light intensity |
Visual pigments | located in the membrane of discs in rods and cones |
Rhodopsin | visual pigment of rods consisting of opsin and retinal |
Photopsin | visual pigment of cones consisting of retinal and three different opsin that have different absorption peaks – for color |
Light adaption | pupil constricts to reduce light intensity |
Dark adaptation | pupil dilates to admit more light into the eye |
The high sensitivity of rods in dim light that stems in part from the neural convergence.. | ..allows for a high degree of spatial summation |
Peripheral vision | visual acuity decreases rapidly as the image forms away from the fovea centralis |
High-resolution images | formed when you look directly at something and its image falls on the fovea because the fovea is only cones which do not converge |
depth perception | the ability to judge how far away objects are |
stereoscopic vision... | ..depends on two eyes with overlapping visual fields looking at the same object from different angles` |
Middle-ear infection | infection spreads from the throat up the auditory tube to the tympanic cavity |
Conductive deafness | any condition that interferes with transmission of vibrations to the inner ear |
Sensorineural deafness | death of hair cells or any of the nervous elements concerned with hearing |
Otosclerosis | fusion of the ossicles to each other or fusion of the stapes to the oval window |
Cataracts | clouding of the lens |
Glaucoma | elevated pressure within the eye that compresses the b.v. that nourish the retina |
Detached retina | the retina separates from the wall of the eyeball |
Astigmatism | deviation in the shape of the cornea causing vertical or horizontal to go out of focus |
Hyperopia | eyeball is too short, causing difficulty seeing near objects |
myopia | eyeball is too long, causing for difficulty seeing far objects |
Presbyopia | reduced ability to accommodate for near vision with age |