3. what are the optic chiasm, optic tract, lgn, optic radiation, striate cortex, v1? course hero

by Ines Waelchi 8 min read

What is the anatomy of the optic chiasm?

Jan 06, 2022 · The optic radiation, also known as the geniculo-calcarine tract, is a relay centre receiving about 80% of the optic tract. The remaining fibres of the optic tract terminate in the pretectal nuclei and superior colliculus. Optic tract and optic chiasm in relation to anterior and middle cerebral arteries. Blood supply

What part of the brain is the optic tract?

The Visual Path-Includes retina, optic nerve, optic chiasm, optic tract, lateral geniculate nucleus (LGN), optic radiation, and striate cortex-Photoreceptor (First Cell) converts light energy to neural signal that is passed to bipolar cell and amacrine cell then to ganglion cell Optic nerve-1-2.22 million optic nerve fibers, from small-diameter macula fibers to larger-caliber (internal ...

What is the path of the optic tract?

What are the optic nerve, optic chiasm, optic tract, LGN, optic radiation, striate cortex, V1? optic chiasm: crossover point for optic nerve fibers Optic tract: fundamental visual sensation LGN: axons convey information to the arterial geniculate nucleus (LGN) in the Thalamus Optic radiation : once in the Thalamus, the Information is then ...

What is the left optic nerve and the optic tract?

Sep 08, 2021 · The optic tracts course posterolaterally through the ambient cistern from the chiasma to the lateral geniculate nucleus of the thalamus. Most axons synapsis with this nucleus and carry visual fibers. A smaller proportion of axons branches off medially from the optic tract to course between the medial and lateral geniculate nuclei and towards ...

What is the optic tract of the eye?

The optic tract is a bundle of nerve fibers that serves to carry visual information from the optic chiasm to the left and right lateral geniculate bodies as a part of the visual pathway.Jul 31, 2021

Is the optic chiasm in the visual cortex?

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....Optic chiasmOptic nerves, chiasm, and optic tractsDetailsSystemVisual system11 more rows

Is optic radiation same as optic tract?

There is one such tract on each side of the brain. If a lesion only exists in one optic radiation, the consequence is called quadrantanopia, which implies that only the respective superior or inferior quadrant of the visual field is affected....Optic radiationFMA61941Anatomical terms of neuroanatomy10 more rows

What forms optic tracts?

The axons of the retinal ganglion cells converge to form the optic nerve, which after a partial decussation at the optic chiasm forms the optic tract. The optic tract is an important part of the visual pathway.

What are the optic chiasm?

Listen to pronunciation. (OP-tik ky-AZ-muh) The place in the brain where some of the optic nerve fibers coming from one eye cross optic nerve fibers from the other eye. Also called optic chiasm.

What occurs in the optic chiasm?

In the optic chiasm, the fibers of the nasal retina (i.e., the temporal visual field) of each eye cross, whereas the fibers of the temporal retina (i.e., the nasal visual field) of each eye proceed uncrossed. Thus, each optic tract contains visual fibers from the same hemifield of each eye.

What is the difference between optic chiasm and optic tract?

The fibers anterior to the intersection of the "X", are optic nerve fibers. Axons caudal to the intersection, called the optic chiasm, are optic tract fibers.

What is striate cortex?

The striate cortex is the part of the visual cortex that is involved in processing visual information. The striate cortex is the first cortical visual area that receives input from the lateral geniculate nucleus in the thalamus.

How is optic nerve chiasm and optic tract anatomically different?

The optical nerve is the nerve which connects your eye to the brain while the optical tract is the continuation of the optical nerve. Therefore, the optical tract is a part of the visual system of the brain. This is the key difference between optic nerve and optic tract.Jul 18, 2018

What artery supplies the optic chiasm?

Blood supply Small branches of the anterior cerebral artery and the superior hypophyseal artery supply the chiasm and intracranial portion of the optic nerves whereas the optic tracts are supplied by small branches of the anterior choroidal and posterior communicating arteries.Mar 22, 2017

Where are the optic tracts?

The optic tract is an extension of the optic nerve located in the brain. It begins at the area where information from the left eye and right eye cross (or “decussate”) to create a complete visual picture.

Where do the optic tracts exist quizlet?

Optic tracts: behind the chiasm where nasal (medial) retina fibers for each eye (responsible for temporal (lateral) hemifields) have crossed over to the other side.

What is the anatomical course of the optic nerve?

The anatomical course of the optic nerve describes the transmission of special sensory information from the retina of the eye to the primary visual cortex of the brain. It can be divided into extracranial (outside the cranial cavity) and intracranial components.

Where does the optic tract travel?

Each optic tract travels to its corresponding cerebral hemisphere to reach the l ateral geniculate nucleus (LGN), a relay system located in the thalamus; the fibres synapse here. Axons from the LGN then carry visual information via a pathway known as the optic radiation.

What is the optic nerve?

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. The optic nerve can therefore be considered part of the central nervous system, ...

What is the second cranial nerve?

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. The optic nerve can therefore be considered part of the central nervous system, and examination of the nerve enables an assessment ...

What is the visual pathway?

Intracranial (The Visual Pathway) Within the middle cranial fossa, the optic nerves from each eye unite to form the optic chiasm. At the chiasm, fibres from the nasal (medial) half of each retina cross over to the contralateral optic tract, while fibres from the temporal (lateral) halves remain ipsilateral:

How is the optic nerve formed?

The optic nerve is formed by the convergence of axons from the retinal ganglion cells. These cells in turn receive impulses from the photoreceptors of the eye (the rods and cones). After its formation, the nerve leaves the bony orbit via the optic canal , a passageway through the sphenoid bone.

Is the optic nerve part of the central nervous system?

The optic nerve can therefore be considered part of the central nervous system, and examination of the nerve enables an assessment of intracranial health. Due to its unique anatomical relation to the brain, the optic nerve is surrounded by the cranial meninges (not by epi-, peri- and endoneurium like most other nerves).

What is the 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. Anthony Lee / Getty Images.

What are the symptoms of pituitary adenomas?

Besides vision changes such as double vision , drooping eyelids, and visual field loss, pituitary adenomas also may cause the following symptoms: 4 . Forehead headaches. Nausea or vomiting. Change in sense of smell.

Where is the pituitary gland located?

The pituitary gland is about the size of a bean and is attached to the base of the brain behind the nasal area. it sits right under the optic chiasm. Although small, the pituitary controls the secretion of many different types of hormones.

Can pituitary adenomas cause vision loss?

In most cases, they have no impact at all, but in some cases, they can affect vision, sometimes causing vision loss. As they grow in size, pituitary adenomas can put pressure on important structures in the body, such as the optic nerve.

What is the optic tract?

The optic tract (from the Latin tractus opticus) is a part of the visual system in the brain. It is a continuation of the optic nerve that relays information from the optic chiasm to the ipsilateral lateral geniculate nucleus (LGN), pretectal nuclei, and superior colliculus. It is composed of two individual tracts, ...

Which tract of the eye carries retinal information?

The optic tract carries retinal information relating to the whole visual field. Specifically, the left optic tract corresponds to the right visual field, while the right optic tract corresponds to the left visual field. To form the right visual field, temporal retinal fibers from the left eye and nasal retinal fibers from the right eye form ...

What is the left optic nerve?

The left optic nerve and the optic tracts. The optic tract (from the Latin tractus opticus) is a part of the visual system in the brain. It is a continuation of the optic nerve that relays information from the optic chiasm to the ipsilateral lateral geniculate nucleus (LGN), pretectal nuclei, and superior colliculus.

What causes pupillary constriction?

Higher light intensity causes pupil constriction, and the increase of light stimulation of one eye will cause pupillary constriction of both eyes. The neural circuitry of the pupillary light reflex includes the optic tract which joins the optic nerve to the brachium of the superior colliculus.

What causes optic tract damage?

A lesion in the left optic tract will cause right-sided homonymous hemianopsia, while a lesion in the right optic tract will cause left-sided homonymous hemianopsia. Stroke, congenital defects, tumors, infection, and surgery are all possible causes of optic tract damage. Peripheral prism expanders and vision restitution therapy are often employed in patients with visual field loss resultant of permanent optic tract damage.

Which motor response is consensual?

Several autonomic ocular motor responses are consensual. The optic tract is primarily responsible for relaying visual information to the LGN, but it is also peripherally responsible for transducing these bilateral autonomic reflexes, including the pupillary light reflex and pupillary dark reflex.