871. Which of the following statements regarding aqueous humor is FALSE?
A. Aqueous humor is produced by ciliary body by active transport
B. Aqueous humor is reabsorbed through the trabecular meshwork into the canal of Schlemn.
C. Canal of Schlemn is found at the anterior chamber angle.
D. Acute angle closure glaucoma is due to the obstruction of anterior chamber angle.
E. Open angle glaucoma is due to reduced permeability of the trabecular meshwork.
872. Which of the followings statements regarding visual reception is INCORRECT?
A. Rods & cones are hidden beneath an array of neurons in the retina.
B. Impulses from rods & cones converge onto a network of neurons & ultimately to the optic nerve.
C. Pigment epithelium absorbs light rays to prevent reflection.
D. Optic disk is situated at the posterior pole of the globe.
E. There are no rods or cones over the optic disk.
873. Which of the following statements about the retina is FALSE?
A. Macula lutea is the point of greatest visual acuity.
B. Retinal blood vessels supply the rods & cones in retina.
C. There are no blood vessels in the macula lutea
D. There are no rods in the macula lutea
E. All of the above
874. Which of the following statements regarding visual pathways is INCORRECT?
A. Objects in the temporal visual field is sensed by the nasal hemiretina
B. Interruption of optic nerve leads to blindness in the ipsilateral eye only
C. Fibers from temporal hemiretina decussate at the optic chiasm
D. Lateral geniculate body receives fibers from the ipsilateral temporal hemiretina& contralateral nasal hemiretina.
875. Which of the following statements regarding visual receptors is FALSE?
A. Outer segment is the photosensitive part of rods & cones that initiates the action potential in the visual pathway.
B. Inner segment is important for the metabolic activity of rods & cones.
C. Rods predominates in the retina (except in the fovea).
D. Cones in the fovea converge onto bipolar nuclei.
E. Cones are more important for acuity & color vision.
876. Which of the following retinal neurons generate “all or none” action potentials?
A. Ganglion cell
B. Bipolar cell
C. Horizontal cell
D. Amacrine cell
E. Rods & cones.
877. Which of the following statement regarding cone & rods is FALSE?
A. Cone receptor potential has sharp onset & offset
B. Rod receptor potential has sharp onset & slow offset
C. Cone responds to a stimulus at a level of illumination below that of rods
D. Both cones & rods generate hyperpolarizing potential when stimulated
E. Sodium channels in the outer segment of rods & cones are closed when strike by light.
878. Which of the following statements regarding lateral geniculate body is TRUE?
A. Each lamina of the lateral geniculate body has a precise mapping of the ipsilateral temporal hemiretina& contralateral nasal hemiretina
B. Lateral geniculate body also receives input from the visual cortex & other brain regions.
C. Magnocellular pathway carries signals for detection of movement & depth to the visual cortex
D. Parvocellular pathway carries signals for texture, shape & fine details to the visual cortex.
E. All of the above
879. Which of the following statements are TRUE?
A. Visual cortex is arranged in 6 layers, each responsible for processing different type of visual information.
B. Parietal cortex, temporal cortex & cingulate gyrus also have 20 visual processing function
C. Reduced visual threshold of cones is responsible for the initial rapid reduction in visual threshold in dark adaptation
D. Time required for dark adaptation is determined by the time required to building rhodospin stores.
E. All of the above
880. Which of the following statements regarding vision is FALSE?
A. Visual acuity is a measurement of visual threshold.
B. Binocular vision relies on the fusion of images from the central visual field of both eyes at the cortical level.
C. Depth can be perceived by monocular vision alone.
D. Bilateral occipital cortical destruction results in subjective blindness but the subject still has residual responses to visual stimuli.
E. Lesions in the lateral geniculate nuclei result in contralateral heteronymous hemianopia with normal pupillary reflex.