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What are the functions of the eye? - regulate amount of light reaching retina- focusing on objects- recording the pattern of incoming light- retina processing- visual acuity. What does light do as it enters eye? passes through lens, forms image on retina that is inverted and reversed (upside down and backwards)
half of visual field on the same side --> stroke. portions on the same side --> optic radiation. small portion --> small stroke in visual cortex. Study with Quizlet and memorize flashcards containing terms like visual system is designed to, visual system involved mechanisms to:, Light has _____-______ properties and more.
The visual pathway to the occipital lobe of the brain consists most simply of a chain of five cells. Beginning with the photoreceptor cell of the retina, name them and note their location in the pathway. 1. photoreceptor cell; retina. 2. bipolar cell; retina. 3. ganglion cell; retina.
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- Retinal Pigmented Epithelium
- Photoreceptor Layer
- Outer Nuclear Layer
- Rods
- Cones
- Inner Nuclear Layer
- Bipolar Cells
- Amacrine Cells
- Horizontal Cells
- Ganglion Cell and Nerve Fiber Layer
The retinal pigmented epithelium is the most superficial (i.e. outermost) layer of the retina. It is made up of simple cuboidal to low columnar epithelium that is affixed to Bruch’s membrane (innermost layer of the choroid). The layer is characterized by numerous mitochondria-rich invaginations into the basement membrane, multiple gap junctions, an...
Humans have two types of photoreceptors that are named according to the morphology of the cell bodies. The rods are cylindrical cells that operate best in low-intensity light; while cones are (surprise!) conical cells that function best in high-intensity light and facilitate color perception. The rods are more often than not, longer and more slende...
Each photoreceptor has four major components. There is an outer segment, inner segment, nucleus, and a synaptic body (spherule). The outer segment is highly folded and contains the photosensitive chemicals necessary for initiating the visual impulse. The membrane of the outer segment is also highly folded into discs to increase the surface area of ...
Rods are ubiquitously distributed throughout the periphery of the retina. Unlike cones, the cylindrical stacks of membrane discs are encased within a membrane. The outer segment of the rods contains high resting levels of cyclic guanosine monophosphate (cGMP) as well as inactive rhodopsin molecules. The inactive rhodopsin moieties are bound to the ...
In contrast to the rods, the conesare not enclosed within a membrane and are in constant communication with the extracellular space. Furthermore, the stacks of discs progressively get smaller and further away from the inner segment. Therefore, the cones have a characteristic conical shape. There are three types of cones, each responsible for detect...
There are several accessory cells within the retina that form regulatory connections with the photoreceptors. Their cell bodies are found in the inner nuclear layerof the retina (between the inner and outer plexiform layers). It contains the cell bodies of amacrine, horizontal, and bipolar cells.
The type of synaptic input that enters a bipolar cell determines whether or not it will be classified as a cone or rod bipolar cell. These cells form the bridges between the ganglion cells and photoreceptors of the retina. They are particularly important in detecting the edges of images sent to the visual system. They are further categorized into “...
The small-bodied amacrine cells do not demonstrate prominent axons, but undergo significant arborization, with their axons extending widely. Several neurotransmitters such as gamma (γ)-aminobutyric acid (GABA), glycine or acetylcholine (ACh), and other neuropeptides can be found in amacrine cells. They regulate the activity of bipolar cells and inc...
The horizontal cells are characterized by cells with axons of varying lengths (to access photoreceptors both near and far) that travel parallel to the retinal plane and numerous dendrites. The cell bodies are restricted to the inner nuclear layer. In response to the glutamine released from the photoreceptors, horizontal cells secrete GABA to nearby...
The second order neurons that form the bridge between the photoreceptors and the lateral geniculate body of the thalamus are the ganglion cells. Their cell bodies are located within the ganglion cell layer, and their nerve fibers travel in the nerve fiber layer(adjacent to the vitreous humor) toward the optic disc. Here, they form the optic nerve. ...
A. The right optic nerve contains fibers from the right eye only; the right optic tract contain fibers from the lateral aspect of the right eye. Study Exercise 23: Special Senses: Anatomy of the Visual System flashcards from Kaitlynn Sholey's GREENBRIER HIGH SCHOOL class online, or in Brainscape's iPhone or Android app. Learn faster with spaced ...
Jan 1, 2016 · Children who are old enough to delineate objects on a wall-mounted or handheld eye chart can provide a direct measurement of visual acuity. For some children, this may be accomplished as young as 3 years, but for the typical healthy child, an accurate visual acuity can be achieved with a high degree of success at 4 years and older.
Optic tract —axons from both eyes. The optic tract conveys contralateral visual field information (i.e., axons from the lateral part of the retina of the ipsilateral eye & the medial & central parts of the retina of the contralateral eye). Binocular vision, which is important for depth perception, requires visual field overlap so that
