Chapter 42: Vision Flashcards
According to the description in chapter two, the retina is an outgrowth of the _____.
- Forebrain (diencephalon)
Vision requires the activity of both the _____ and the _____.
- Eyes
- Brain
The optic nerve is made up of the _____ of the ganglion cells of the retina.
- Axons
A small number of the axons in the optic nerve reach the _____ and the _____ nucleus via the brachium of the superior colliculus.
- Superior colliculus
- Pretectal
The overwhelming majority of the axons in the optic nerve synapse in the _____ of the _____.
- Lateral geniculate nucleus
- Thalamus
As noted in chapter 34, each lateral geniculate nucleus receives information about the _____ visual field from ganglion cells in both retinas.
- Contralateral
Ganglion cells in the right halves of both retinas send information about the _____ visual field to the _____ lateral geniculate nucleus.
- Contralateral
- Ipsilateral
Axons from the _____ half of the left retina must cross over in the optic chiasma to reach the _____.
- Right (medial)
- Right lateral geniculate nucleus
Since the _____ nucleus of the hypothalamus is just above it, the optic chiasma must be just _____ to the pituitary stalk which descends below the arcuate nucleus.
- Suprachiasmatic
- Anterior (rostral)
Each of the optic tracts that run from the optic chiasma to the lateral geniculate nuclei is made up of 50% axons from the _____ side of the ipsilateral retina and 50% axons from the _____ side of the contralateral retina.
- Ipsilateral
- Ipsilateral
Because the lens system of the eye reverses and _____ the image, information about the right visual field reaches the _____ lateral geniculate nucleus through the _____ optic nerve and the _____ optic tract.
- Inverts
- Left
- Right
- Left
Information about the upper visual field reaches the _____ half of each lateral geniculate nucleus in the ipsilateral _____.
- Lower
- Optic tract
The lower half of each lateral geniculate nucleus projects visual information from the _____ half of the visual field to the lower half of the ipsilateral posterior occipital cortex, Brodmann area 17.
- Upper
The upper half of each lateral geniculate nucleus projects visual information from the _____ half of the visual field to the upper half of the ipsilateral posterior occipital cortex, Brodmann area 17.
- Lower
Brodmann area _____ is the primary visual cortex.
- 17
The primary visual cortex, Brodmann area _____, is the posterior third of the _____ lobe.
- 17
- Occipital
The primary visual cortex is often called the calcarine cortex because its medial surface is split into upper and lower halves by the _____ sulcus.
- Calcarine
The calcarine artery, which is a branch of the posterior cerebral artery, usually runs in the opening of the _____ sulcus.
- Calcarine
The primary visual cortex is completely dependent on the _____ for its blood supply unless there is an anastomosis with an occipital branch of the middle cerebral artery on the lateral surface of the occipital lobe.
- Calcarine sulcus
The half of each primary visual cortex above the _____ receives visual information about the _____ half of the _____ visual field.
- Calcarine sulcus
- Lower
- Contralateral
The upper half of each lateral geniculate nucleus projects to the _____ half of the _____ calcarine cortex through the superior geniculocalcarine tract.
- Upper
- Ipsilateral
The half of each primary visual cortex below the _____ receives visual information about the _____ half of the _____ visual field.
- Calacarine sulcus
- Upper
- Contralateral
The lower half of each lateral geniculate nucleus projects to the _____ half of the _____ calcarine cortex through the inferior geniculocalcarine tract.
- Lower
- Ipsilateral
When the temporal lobe grew down from the _____ lobe during the first trimester it took a loop of the _____ geniculocalcarine tract with it.
- Occipital
- Ipsilateral
The loop of the inferior geniculocalcarine tract inside the posterior part of the _____ lobe is called Meyer’s loop.
- Temporal
_____ makes the inferior geniculocalcarine tract longer than the superior geniculocalcarine tract.
- Meyer’s Loop
A lesion in one part of the visual system causes a dark region in the perceived visual fields. The dark region is called a scotoma from the Greek word for _____, “scotos.”
- Dark
One can find the lesion by analyzing the pattern of a _____.
- Scotoma
Loss of both right and left visual fields of one eye is the easiest _____ to analyze.
- Scotoma
Complete scotoma of one eye is due to loss of the _____ nerve or loss of the eye itself.
- Optic
The optic nerve can be attacked by multiple sclerosis because it is part of the _____ system.
- Central nervous
The ophthalmic artery runs alongside the optic nerve and supplies it. An aneurysm of the ophthalmic artery will press on the optic nerve and _____ its function.
- Impair (degrade)
Destruction of the retina will cause the same scotoma as destruction of the _____.
- Optic nerve
The retina is completely dependent on the central artery of the retina, which is a branch of the ophthalmic artery. Thus, occlusion of the ophthalamic artery or the central artery of the retina destroys the _____ and leaves that eye _____.
- Retina
- Blind
A thrombus in the ophthalmic artery, unless promptly dissolved, will _____ the _____ nerve.
- Destroy (infarct)
- Optic nerve
For there to be a chance of restoring vision after occlusion of the central artery of the retina, the _____ must be removed within 4 hours.
- Clot (obstruction)
In a case of central artery occlusion the window of opportunity for restoring sight is only _____.
- 4 hours
Monocular scotoma may be due to destruction or loss of function of the _____ or the _____.
- Retina
- Optic nerve
Loss of function may be due to an _____.
- Aneurysm
Destruction may be due to _____ of the _____ artery or the _____ of the _____.
- Occlusion
- Ophthalmic
- Central artery
- Retina
Destruction of one optic tract causes loss of the contralateral visual field of both eyes. Hemianopia is the loss of _____ of one’s range of vision. Hemianopia is homonymous if and only if both eyes lose the right visual field or both eyes lose the left visual field.
- Half
Only the axons from the left sides of the retinas are cut. Thus only the _____ visual field is lost.
- Right (contralateral)
Each lateral geniculate nucleus relays information about the contralateral visual field to the calcarine cortex. Damage to the left lateral geniculate nucleus would cause _____.
- Right homonymous hemianopia