Currently Skimming:
Glossary
Glossary
Pages 493-508
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 493... ...
Glossary The jargon and technical terms of one discipline are deterrents to understanding by readers trained in another discipline. This glossary is intended to relieve the irritation of reading material in an unfamiliar subject and to promote comprehension.
|
From page 494... ...
"ACUTE" INVESTIGATIONS: In neurophysiology, usually investigations on anesthetized animals that are sacrificed at the termination of the experiment, in contrast to "chronic" animals, which are used more than once. AMACRINE CELLS: Intraretinal association neurons without long extensions, acting on synaptic junctions between bipolar and ganglion cells; one of several types of association cells facilitating or inhibiting retinal neural activity.
|
From page 495... ...
A-WAVE: Negative deflection of the electroretinogram occurring in the lightadapted eye following stimulation by a flash of light, or in the dark-adapted eye by a red light, and considered to be related to cone activity. AX ON : A nerve-cell expansion or process that is typically single and long, terminates in short branches relatively far from the cell body, and usually conducts impulses away from the cell body.
|
From page 496... ...
DENDRITE: A protoplasmic expansion or process of a neuron that usually terminates in a highly branched state relatively near the cell body and conducts impulses toward the cell body. Dendrites of pyramidal cells are termed apical dendrites or basilar dendrites depending on where they leave the cell body, which is oriented with the apex toward the cerebrocortical surface.
|
From page 497... ...
EMMETROPIA: A state of proper correlation between the refractive system of the eye and the axial length of the eyeball such that rays of light entering the eye parallel to the optic axis are brought to a focus on the retina. ENUCLEATION: Removal of the eyeball after the extraocular muscles and optic nerve have been severed.
|
From page 498... ...
FUSIONAL MOVEMENTS: Movements of the eyes that bring the retinal images of the same part of a visual stimulus sufficiently close to corresponding points of the retina that a single image is perceived. GANGLION CELLS: In the retina, neurons representing the third link in the chain that carries visual stimuli to the brain, whose cell bodies and dendrites are in the retina and whose axons constitute the fibers of the optic nerve.
|
From page 499... ...
LATERAL GENICULATE NUCLEUS: A group of neuronal cell bodies arranged in six layers. Nerve fibers from the retina of the contralateral side are received in layers 1,4, and 6, and from equivalent spots of the ipsilateral retina, in layers 2, 3, and 5.
|
From page 500... ...
MACULA LUTEA RETINAE: The part of the retina distinguished from the remainder of the retina by its yellow appearance; in the center lies ihefovea centralis, the area of greatest visual acuity. MEANING-EMPHASIS PROGRAMS: Programs of teaching reading that emphasize language meaning, as distinct from code-emphasis programs.
|
From page 501... ...
: In neuroanatomy, a general term used to designate a group of nerve-cell bodies usually within the central nervous system and bearing a direct relationship to the fibers of a particular nerve. OCCIPITAL LOBE: The posterior lobe of the cerebral hemisphere, merging laterally with the temporal lobe, and concerned primarily with visual input.
|
From page 502... ...
OPTIC TRACTS: The tracts by which the optic nerves continue from the optic chiasma to the brain. The tract on each side carries fibers conducting impulses set up by contralateral visual fields that fall on the ipsilateral retinas, the fibers from the opposite eye having crossed over at the chiasma.
|
From page 503... ...
PRIMARY VISUAL SYSTEM: The nerve system that conducts impulses from the retina to the cortical, thalamic, and collicular regions of the brain. PROPRIOCEPTIVE END ORGANS: Sensory nerve receptors that give information concerning movements and position of the body; found chiefly in muscles, tendons, and the vestibular apparatus.
|
From page 504... ...
: A diffuse network or reticulum of nerve cells and fibers, forming the core of the brain stem, that when stimulated produce "arousal." This system is concerned with such general effects as alerting the entire organism, maintaining attention, controlling muscular activity, and regulating receptivity of peripheral sensory end organs. RETINAL CONTRAST: Physiologic processes in the retina that produce noticeable subjective differences between objects of different luminosities placed side by side.
|
From page 505... ...
: A condition in which the reading age is below 90% of expectation with respect to measured intelligence and educational opportunity, but with no evidence of structural defect of the central nervous system and with peripheral sensory apparatus sufficiently intact for the recognition of sensory stimuli involved in reading. There is evidence that this is due to an inherited lag in the maturation of neurophysiologic functions (as yet unidentified)
|
From page 506... ...
STEREOPSIS: The sensation of relative visual depth that results from the neural integration of dissimilarities in the images seen by the two eyes. STRABISMUS: Deviation of the eye that a subject cannot overcome; the visual axes of the two eyes assume a position relative to each other different from that required by the visual stimulus conditions.
|
From page 507... ...
VESTIBULAR MOVEMENTS: Reflex movements of the eyes initiated by impulses from the vestibular apparatus in the inner ear due to rotation of the head. VISUAL CLIFF: A sharp vertical discontinuity in visual space, such as the edge of a desk, either real or contrived by optical illusion.
|
From page 508... ...
: The paired nerve tracts or fiber system carrying visual impulses from the lateral geniculate nucleus to the highest brain center of vision, the striate area. VISUAL RESOLVING POWER: A measure of visual acuity or the ability of the eye to discriminate or resolve small visual stimulus differences.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.