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Questions and Answers
What percentage of visual fibers terminate in the Lateral Geniculate Nucleus (LGN)?
What percentage of visual fibers terminate in the Lateral Geniculate Nucleus (LGN)?
Which of the following is a characteristic of the optic nerve fibers?
Which of the following is a characteristic of the optic nerve fibers?
What is the name of the structure where the optic tract carries fibers from the chiasm?
What is the name of the structure where the optic tract carries fibers from the chiasm?
Which segment of the optic nerve is characterized by an S-shaped movement around the sphenoid bone?
Which segment of the optic nerve is characterized by an S-shaped movement around the sphenoid bone?
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What is the name of the condition that damages the optic nerve fibers?
What is the name of the condition that damages the optic nerve fibers?
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Which artery supplies the posterior radiations of the optic radiations?
Which artery supplies the posterior radiations of the optic radiations?
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What is the pattern of fibers in the retina from the nasal side?
What is the pattern of fibers in the retina from the nasal side?
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Which part of the retina is responsible for the visual field defect in the event of damage to the afferent pathway?
Which part of the retina is responsible for the visual field defect in the event of damage to the afferent pathway?
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What is the blood supply to the striate cortex?
What is the blood supply to the striate cortex?
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What is the primary function of astrocytes in the optic nerve?
What is the primary function of astrocytes in the optic nerve?
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In the intracanalicular and intracranial segments of the optic nerve, what happens to the papillomacular bundle?
In the intracanalicular and intracranial segments of the optic nerve, what happens to the papillomacular bundle?
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Which of the following vessels supplies blood to the optic nerve?
Which of the following vessels supplies blood to the optic nerve?
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What is the significance of the lamina cribrosa in the optic nerve?
What is the significance of the lamina cribrosa in the optic nerve?
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What is the characteristic of retinal fibers as they pass through the scleral perforations of the lamina cribrosa?
What is the characteristic of retinal fibers as they pass through the scleral perforations of the lamina cribrosa?
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What is the correct sequence of events for retinal fibers in the optic nerve?
What is the correct sequence of events for retinal fibers in the optic nerve?
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Which part of the visual pathway is responsible for receiving visual information from the nasal fibers of each eye?
Which part of the visual pathway is responsible for receiving visual information from the nasal fibers of each eye?
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What is the consequence of damage to the nasal fibers of the optic nerve?
What is the consequence of damage to the nasal fibers of the optic nerve?
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What is the term for the connective tissue that surrounds the central retinal vessels throughout its course in the optic nerve?
What is the term for the connective tissue that surrounds the central retinal vessels throughout its course in the optic nerve?
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What is the outermost layer of the meningeal sheaths surrounding the optic nerve?
What is the outermost layer of the meningeal sheaths surrounding the optic nerve?
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Which part of the visual pathway is responsible for transmitting visual information to the primary visual cortex?
Which part of the visual pathway is responsible for transmitting visual information to the primary visual cortex?
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What is the name of the space that contains cerebrospinal fluid and lies between the arachnoid and pia mater?
What is the name of the space that contains cerebrospinal fluid and lies between the arachnoid and pia mater?
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What is the embryological origin of the optic nerve?
What is the embryological origin of the optic nerve?
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What is the characteristic of the optic nerve fibers that are not myelinated?
What is the characteristic of the optic nerve fibers that are not myelinated?
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Which structure penetrates as far as the central retinal artery in the middle of the optic nerve?
Which structure penetrates as far as the central retinal artery in the middle of the optic nerve?
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What is the term for the arrangement of the myelinated nerve fascicles in the orbital portion of the optic nerve?
What is the term for the arrangement of the myelinated nerve fascicles in the orbital portion of the optic nerve?
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What is the characteristic visual field defect associated with a lesion in the left parietal lobe?
What is the characteristic visual field defect associated with a lesion in the left parietal lobe?
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A lesion in the left optic tract can cause which of the following visual field defects?
A lesion in the left optic tract can cause which of the following visual field defects?
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What is the term for the visual field defect caused by pressure exerted on the optic chiasm by a pituitary tumor?
What is the term for the visual field defect caused by pressure exerted on the optic chiasm by a pituitary tumor?
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What is the term for the visual field defect caused by inflammation of the optic disk or optic nerve?
What is the term for the visual field defect caused by inflammation of the optic disk or optic nerve?
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What is the term for the visual field defect caused by a lesion in the left temporal lobe, affecting the optic radiation?
What is the term for the visual field defect caused by a lesion in the left temporal lobe, affecting the optic radiation?
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What is the primary function of the border tissue of Jacoby?
What is the primary function of the border tissue of Jacoby?
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What is the significance of the spur of collagenous tissue in the optic nerve head?
What is the significance of the spur of collagenous tissue in the optic nerve head?
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What is the characteristic of retinal fibers as they pass through the optic nerve head?
What is the characteristic of retinal fibers as they pass through the optic nerve head?
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What is the role of the intermediary tissue of Kuhnt in the optic nerve head?
What is the role of the intermediary tissue of Kuhnt in the optic nerve head?
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What is the significance of the lamina cribrosa in the optic nerve head?
What is the significance of the lamina cribrosa in the optic nerve head?
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What is the characteristic of the marginal tissue of Elsching in the optic nerve head?
What is the characteristic of the marginal tissue of Elsching in the optic nerve head?
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What is the significance of the astroglial membrane in the optic nerve head?
What is the significance of the astroglial membrane in the optic nerve head?
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What is the characteristic of the optic nerve fibers in the intracranial segment?
What is the characteristic of the optic nerve fibers in the intracranial segment?
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What is the significance of the central meniscus of Kuhnt in the optic nerve head?
What is the significance of the central meniscus of Kuhnt in the optic nerve head?
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What is the characteristic of the retinal fibers in the optic nerve head?
What is the characteristic of the retinal fibers in the optic nerve head?
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Study Notes
Visual Pathway
- The visual pathway consists of the series of cells and synapses that carry visual information from the environment to the brain for processing
- Includes: retina, optic nerve, optic chiasm, optic tract, Lateral Geniculate Nucleus (LGN), optic radiations, and primary visual cortex
Optic Nerve
- Carries visual information from the eye to the brain
- Divided into four segments: intraocular, intraorbital, intracanalicular, and intracranial
- The optic nerve head is the part of the optic nerve that leaves the eye and enters the optic chiasm
- Contain unmyelinated axons that become myelinated by oligodendrocytes in the optic nerve
Histology of the Optic Nerve Head
- The optic nerve head consists of the surface nerve fiber layer, the physiologic cup, and the lamina cribrosa region
- The three layers of meninges surrounding the nerve are clearly visible: dura, arachnoid, and pia mater
- Blood supply of the optic nerve includes branches from the central retinal artery, circle of Zinn-Haller, choroidal branches, and pial branches
Blood Supply to the Visual Pathway
- Optic radiations are supplied by the anterior choroidal artery and the middle cerebral artery
- Striate cortex is supplied by the calcarine branch of the posterior cerebral artery
- Visual cortex is supplied by the posterior cerebral artery
Fiber Orientation in the Retina
- Axons of the ganglion cells are arranged in three basic patterns: papillomacular bundle, superior and inferior temporal fibers, and radial fibers from the nasal retina
- In the optic disc, nasal fibers radiate directly to the nasal side, while the papillomacular bundle courses directly to the temporal side
Fiber Orientation in the Optic Chiasm
- Temporal fibers remain uncrossed
- Nasal fibers decussate (cross) to the opposite side of the brain
Embryological Development
- The optic nerve develops from the optic stalk by axons of the ganglion cells
- Myelination of the axons within the optic nerve begins shortly before birth and continues after birth
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Description
Test your knowledge of the visual pathway, from the optic tract to the visual cortex, and learn about the effects of glaucoma on optic nerve fibers. Explore the anatomy of the optic nerve and its role in visual processing.
