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प्रश्न
Explain the following:
Mechanism of generation of light-induced impulse in the retina.
उत्तर
Retina is the innermost layer of the eye. It contains three layers of cells – inner ganglion cells, middle bipolar cells, and outermost photoreceptor cells. Photoreceptor cells are composed of a protein called opsin and an aldehyde of vitamin A called retinal. When light rays are focused on the retina through the cornea, retinal gets dissociated from opsin. As a result, the structure of opsin gets changed. This in turn causes the permeability of the membrane to change, thereby generating a potential difference in the cells. Consequently, an action potential is generated in the ganglion cells and is transmitted to the visual cortex of the brain via the optic nerves. In the cortex region of the brain, the impulses are analysed and the image is formed on the retina.
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संबंधित प्रश्न
Write the function of retina in human eye.
The human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to ______.
Distinguish between: blind spot and yellow spot
The optical prescription for a pair of spectacles is :
Right eye : −3.50 D
Left eye : −4.00 D
Which lens has a greater focal length?
Name the part of the retina which is insensitive to light.
Draw a simple diagram of the human eye and label clearly the cornea, iris, pupil, ciliary muscles, eye-lens, retina, optic nerve and blind spot.
A man driving a car can read a distant road sign clearly but finds difficulty in reading the odometer on the dashboard of the car. Which of the following statement is correct about this man?
(a) The near point of his eyes has receded away.
(b) The near point of his eyes has come closer to him.
(c) The far point of his eyes has receded away.
(d) The far point of his eyes has come closer to him.
Note the relationship between the first two words and suggest the suitable word/words for the fourth place.
Cones : Iodopsim :: Rods : ______.
With reference to the functioning of the eye, answer the question that follow:
Name the cells of the retina and its respective pigments which get activated in the light.
Give the main function of the following:
Three semicircular canals
Name the following:
The opening through which light enters the eyes.
Choose the correct answer.
In the chemistry of vision, the photosensitive substance is _________________
Choose the correct answer.
Aperture controlling passage to light into the eye is ___________
Differentiate between:
Yellow spot and Blind spot.
______ is a transparent layer.
______ of the eye is comparable to the film of a camera.
Chris was watching the display of fireworks in the sky.
- Trace the path of the light rays using the following terms:
Fovea, Lens, Conjunctiva, Pupil, Cornea. - Name the nerve that carries the impulse for vision to the brain.
Name the following:
Place of best vision in the retina of the eye.
With reference to human eye answer the question that follow:
Name the part of the eye associated with the layer providing nourishment to the eye.
