Nervous System
Why does the eye have a blind spot?
Here the layer of ganglion cells and bipolar cells that overlies the retina is absent; hence, the rods and cones are insensitive to light.
This may be due to damage to the retina from exposure to extremely bright light.
At this place the retina is detached from the sclera to allow blood vessels to enter the eye.
Axons from the ganglion cells converge here to leave the eye as the optic nerve; hence, there are no rods or cones.
Axons from the ganglion cells converge here to leave the eye as the optic nerve; hence, there are no rods or cones.
There is no retina at the blind spot (or optic disc) as it is the exit point for the axons of the ganglion cells. These axons form the optic nerve and the optic disc is also the entry point for the retinal artery and vein. Choice A is incorrectly describing the fovea centralis.
Axons from the ganglion cells converge here to leave the eye as the optic nerve; hence, there are no rods or cones. There is no retina at the blind spot (or optic disc) as it is the exit point for the axons of the ganglion cells. These axons form the optic nerve and the optic disc is also the entry point for the retinal artery and vein. Choice A is incorrectly describing the fovea centralis.
Related posts
In the spinal cord, the ascending tracts contain:A. White matter and transmit sensory information
B. White matter and transmit motor commands
C. Grey matter and transmit sensory information
D. Grey matter and transmit motor commands
Which sequence of ion movements describes the action potential?
A. Na+ move out of cell then K+ move in
B. K+ move in to cell then Na+ move out
C. K+ move out of cell then Na+ move in
D. Na+ move into cell then K+ move out
Which of the following substances is prevented from entering the brain by the blood-brain barrier?
A. Glucose
B. Nicotine
C. Pharmaceuticals
D. Alcohol
There are three ossicles in the middle ear. What are their names?
A. Malleus, stapedius, otolith
B. Cochlea, stapes, incus
C. Stapedius, ampulla, cochlea
D. Malleus, stapes, incus
The inner ear (or internal ear) may be described as a series of tubes. What are the tubes filled with?
A. Air
B. Perilymph
C. Endolymph
D. Perilymph and endolymph
What characterises a spinal reflex?
A. It involves rapid processing by the brain and a predictable response.
B. It is a predictable, unlearned and involuntary motor response.
C. It is a rapid, predictable, learned and involuntary motor response.
D. It involves stimulation of a motor neurone by a sensory neurone that originates within the CNS.
A multipolar neuron has more than one of what?
A. Dendrite attached to the cell body
B. Axon attached to the cell body
C. Synaptic terminal attached to the axon
D. Cell body
Leave a Reply