Where the fibers from the medial right and left retina cross?
At the optic chiasm the fibers from the medial part of each retina cross to project to the other side of the brain while the lateral retinal fibers continue on the same side.
Where does the optic nerve originate in the brain?
The optic nerve (CN II) is the second cranial nerve, responsible for transmitting the special sensory information for vision. It is developed from the optic vesicle, an outpocketing of the forebrain.
Where does the optic nerve start and where does it end?
The optic nerve begins at the optic disk, a structure that is 1.5 mm (0.06 inch) in diameter and is located at the back of the eye. The optic disk forms from the convergence of ganglion cell output fibres (called axons) as they pass out of the eye.
Which fibers cross the midline at the optic chiasm?
Axons from ganglion cells in the nasal retina cross the midline in the optic chiasm so that their information goes to the visual centers of the opposite side of the brain. The axons from the temporal retina do not cross the midline and their information goes to the cerebral cortex of the same side.
What part of the brain controls the optic nerve?
To produce sight, the eyes capture information and send it through the optic nerve to be processed by the occipital lobe. The brain also incorporates other information, such as sensory stimuli, to result in the application of sight, such as picking up an object.
What are symptoms of optic nerve damage?
- Pain. Most people who develop optic neuritis have eye pain that’s worsened by eye movement.
- Vision loss in one eye. Most people have at least some temporary reduction in vision, but the extent of loss varies.
- Visual field loss.
- Loss of color vision.
- Flashing lights.
Is the optic chiasm in the frontal lobe?
It is located at the bottom of the brain immediately inferior to the hypothalamus. The optic chiasm is found in all vertebrates, although in cyclostomes (lampreys and hagfishes), it is located within the brain.
What is the main function of optic chiasm?
The optic nerve connects the brain to the eye. To biologists, the optic chiasm is thought to be a turning point in evolution. 1 It is thought that the crossing and uncrossing optic nerve fibers that travel through the optic chiasm developed in such a way to aid in binocular vision and eye-hand coordination.
Which is nerve carries visual information to the brain?
The optic nerve (II): This nerve carries visual information from the retina of the eye to the brain. The oculomotor nerve (III): This controls most of the eye’s movements, the constriction of the pupil, and maintains an open eyelid.
Where is the optic nerve located in the nervous system?
The optic nerve is ensheathed in all three meningeal layers (dura, arachnoid, and pia mater) rather than the epineurium, perineurium, and endoneurium found in the peripheral nerves. The fiber tracks of the mammalian central nervous system are incapable of regeneration. As a consequence, optic nerve damage produces irreversible blindness.
Where are the cranial nerves located in the spinal cord?
Cranial Nerve Anatomy and Terminology Spinal nerves emerge sequentially from the spinal cord with the spinal nerve closest to the head (C1) emerging in the space above the first cervical vertebra. The cranial nerves emerge from the central nervous system above this level. Each cranial nerve is paired and is present on both sides.
What are the functions of the medulla and midbrain?
It contains numerous cranial nerve nuclei and is traversed by multiple tracts between the brain and spinal cord. Improved MRI resolution now allows the radiologist to identify a higher level of anatomic detail, but an un- derstanding of functional anatomy is crucial for correct interpreta- tion of disease.