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Fovea | point on the retina with the greatest acuity and the greatest number of cone cells |
Incus | one of three small bones in the middle ear |
Ion | a charged atom or group of atoms |
Iris | coloured part of the eye, controls the amount of light entering the eye |
Schwann Cells | a type of cell that produces the myelin sheath around nerve cells |
Sclera | tough white coating in the eye |
Sex-inked | a gene found on one of the sex chromosomes |
Sound shadow | the acoustic shadow cast by the head, used in the localisation of sound |
dendrite | extension of a neurone that transmits the signal towards the cell body. |
effector | a muscle or gland that produces a response to a stimulus |
Spike | graphical interpretation of the firing of a neurone |
Stapes | the third bone in the middle ear, part of the ossicles |
Stereocilia | hair-like extensions on hair cells that contact the tectorial membrane and send an impulse to the brain |
Stereoscopic | three dimensional view using the overlapping field of view from two eyes |
Stimuli | an external message that excites a receptor |
Stimulus | singular of stimuli |
Labyrinth | organ in the inner ear that is responsible for balance |
Lateral line | a visible line along the head and body of fish and amphibians, senses low frequency sound |
Malleus | first of three small bones in the middle ear |
Mechanoreceptors | a receptor that responds to sound, pressure, touch, and position |
Optic Nerve | nerve that leaves the retina of the eye |
Otolith | calcareous mass found in the ear of some vertebrates, important in sound perception in fish |
Oval window | the connecting plate between the middle ear and inner ear |
Peripheral | on the outer side |
Pheromones | chemicals released as a signal |
Receptors | detect changes in the environment |
Recessive | not expressed in the phenotype unless it is the only gene present |
Refraction | bending of light |
Refractory period | the time taken for a neurone to recover after firing |
Accomodation | changing the focus in the eye by changing the shape of the lens using the ciliary muscles |
Action potential | reversal of voltage across a nerve membrane caused by the movement of sodium and potassium ions |
Acuity | sharpness of vision |
Aqueous humour | transparent fluid that lies between the cornea and the lens |
Axon | an extension on a neurone that takes the impulse away from the cell body |
Bioncular | involving the use of two eyes with overlapping field of view resulting in depth perception |
Bioluminescence | the production of light by living organisms |
Blind spot | the place on the retina where the optic nerve leaves the eye, contains no light sensitive cells |
Cornea | transparent layer at the front of the eye that refracts incoming light |
Conjunctiva | membrane lining the outer layer of the eye |
Cone Cell | light sensitive cell found on the retina of the eye, important in color perception |
Color Blind | inability to detect particular colors caused by a lack of specific color cone cells |
Ciliary Muscles | small muscles attached to the lens that change the shape of the lens to focus on near and far objects |
Ciliary Body | contains suspensory ligaments and the ciliary muscles in the eye |
Choroid | a layer between the sclera and retina |
Cell Body | part of the neurone that contains the nucleus and other organelles |
Cataract | a clouding of the eye's lens |
Photoreceptor | an organ or cell, sensitive to light |
Pitch | function of the frequency of a wave, high or low sounds have high or low pitch |
Polarisation | separation of positive and negative ions |
Pupil | the opening in the iris of the eye |
Receptors | detect changes in the environment |
Recessive | not expressed in the phenotype unless it is the only gene present |
Refraction | bending of light |
Refractory Period | the time taken for a neurone to recover after firing |
Resting Potential | the normal state of neurone, negatively charges internally |
Retina | light sensitive lining on the back of the eye |
Rhodopsin | Light sensitive pigment found in rod cells |
Rod Cells | light sensitive cells especially useful for the detection of light |
Schwann Cells | a type of cell that produces the myelin sheath around nerve cells |