Term | Definition |
Sensory Receptors | Specialized ends of sensory neurons that detect sensory information and send an electrochemical signal to the brain. |
Sensation | the "feeling" that results when neural impulses arrive at cerebrel cortex. |
Perception | Each person's unique interpretation of sensory information |
Sensory Adaptation | Decrease in responsiveness of a sensory receptor during continued stimulation. |
Photoreceptors | Light (rods/cones) |
Chemoreceptors | Taste/Odor |
Mechanoreceptors | Touch, pressure, pain, hearing, balance. |
Thermoreceptors | Temperature |
Sclera | Tough white outer covering of the eyeball; extra-ocular muscles attach to move eye. |
Cornea | Transparent tissue covering the front of they eye; does not have blood vessels; does not have nerves; is an extension of the sclera. |
Choroid | Thin tissue darkly pigmented layer containing blood vessels located between the sclera and retina. |
Iris | Circular band of muscles that controls the size of the pupil. |
Pupil | "Hole" in the center of the eye where light passes through. |
Adaptation | The process by which the iris adjusts the size of the pupil based on the light conditions, thereby controlling the amount of light that enters. |
Retina | Layer of tissue on the back portion of the eye that contains cells responsive to light called photoreceptors. |
Rods | used for night vision, dominate peripheral vision - found in high concentrations in the periphery of retina |
Cones | Located throughout retina, concentrated on fovea centralis & macula
-3 different types: red, green and blue. |
Optic Nerve | Bundle of over one millions axons from gangolian cells that carry visual signals from the eye to the thalamus to the occipital love of the brain. |
Aqueous Humour | Clear watery fluid found in the front chamber of the eye; maintains pressure and nourishes the cornea and lens. |
Glaucoma | Chaneels that drain aqueous humor from front of the eye become blacked --> pressure buildup eyeball. |
Vitreous Humour | Clear jelly-like fluid found in the back portion of the eye; maintains shape of eye and attaches to the retina. |
Lens | Transparent tissue that bends light passing through the eye; to focus light; this structure must change shape. |
Accomodation | Focusing the lens by contracting or relaxing ciliary muscles. |
Cataracts | Clouding of the lens or cornea. |
Astigmatism | Irregularly shaped lens or cornea results in failure to focus sharply. |
Myopia | Near-Sighted. Lens is too round or eyeball is too long. |
Hyperopia | Far-Sighted. Lens is too flat, or eyeball is too short. |
Fovea Centralis | Central part of the macula that provides the sharpest vision; contains only cones. |
Colour Blindness | Inability to distinguish between or recognize some colours, typically shades of red and green. |
Blind Spot | Small area of the retina where the optic never leaves the eye; any image falling here will not be seen because there are no photoreceptors |
Sounds Waves | Small fluctuation in air pressure resulting from sound, which causes particles around the source to vibrate and move. |
Outer Ear | External Ear & Auditory Canal |
Pinna | The outside flap of the ear; made of skin and cartilage and shaped in a way that enhances sound vibrations and focuses them into the ear. |
Auditory Canal | Carries sound eaves to ear drum |
Middle Ear | Eustachain Tube, Tympanic Membrane & Ossicles |
Tympanum | Sound eaves in auditory canal cause vibrations |
Ossicles | 3 Tiny bones (hammer/malleus, anvil/incus, stirrup/stapes) linking eardrum and inner ear |
Oval Window | Receives sound vibrations from ossicles then transmits into cochlea. |
Eustachian Tube | Chamber to throat to equalize air pressure in middle ear. |
Inner Ear | has two functions: hearing(cochlea) and perfection of head movement/balance(vestibule) |
Cochlea | Perceives both pitch and loudness. |
Organ of Corti | Primary sound receptor with two membranes |
Basilar Membrane | Contains mechanoreceptor hairs, vibrates when sound waves pass cochlear fluid |
Hair Cells | Sensory mechanoreceptor attached to the basilar membrane in the organ of Corti within the inner ear. |
Tectorial Membrane | Receptor hairs bend against this membrane when basilar membrane vibrates. |
Semicircular Canals | Sensation of rotational movement; mechanoreceptor hairs are bent when fluid in the semicircular canals is moved by motion of the head and body. |
Rotational Equilibrium | Balance required while rotating the head and body. |
Gravitational Equilibrium | Balance required while moving the head forward and backward. |
Utricle & Saccule | Sensation of head position & the pull of gravity; mechanoreceptor hairs are bent by the force of gravity when the head tilts. |
Otoliths | Calcium carbonate granule associated with sensory receptors for detecting movement of the head. |
Proprioceptors | Type of mechanoreceptor found in muscles, tendons, and joints. |
Taste Buds | Sensory receptor in the bumps on the tongue. |
Olfactory Cells | Chemoreceptor for the sense of smell. |
Olfactory Bulb | Region of forebrain where ends of sensory nerve fibers from nose terminate and transmit olfactory information to other areas of the brain. |