optic vesicle (redirected from Optic vesicles)

vesicle /ves·i·cle/ (ves´ĭ-k'l)

1. a small bladder or sac containing liquid.

2. a small circumscribed elevation of the epidermis containing a serous fluid; a small blister.

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acrosomal vesicle  a membrane-bounded vacuolelike structure which spreads over the upper two-thirds of the head of a spermatozoon to form the head cap.

auditory vesicle  otic v.

blastodermic vesicle  blastocyst.

brain vesicles , cephalic vesicles, cerebral vesicles the five divisions of the closed neural tube in the head of the developing embryo, including the telencephalon, diencephalon, mesencephalon, metencephalon, and myelencephalon.

chorionic vesicle  see under sac.

encephalic vesicles  brain v's.

germinal vesicle  the fluid-filled nucleus of an oocyte toward the end of prophase of its first meiotic division.

lens vesicle  a vesicle formed from the lens pit of the embryo, developing into the crystalline lens.

matrix vesicles  small membrane-limited structures at sites of calcification of the cartilage matrix.

olfactory vesicle 

1. the vesicle in the embryo that later develops into the olfactory bulb and tract.

2. a bulbous expansion at the distal end of an olfactory cell, from which the olfactory hairs project.

optic vesicle  an evagination on either side of the forebrain of the early embryo, from which the percipient parts of the eye develop.

otic vesicle  a detached ovoid sac formed by closure of the otic pit in embryonic development of the external ear.

primary brain vesicles  the three earliest subdivisions of the embryonic neural tube, including the prosencephalon, mesencephalon, and rhombencephalon.

secondary brain vesicles  the five brain vesicles formed by specialization of the prosencephalon (telencephalon and diencephalon), mesencephalon, and rhombencephalon (metencephalon and myelencephalon) in later embryonic development.

seminal vesicle  either of the paired sacculated pouches attached to the posterior urinary bladder; the duct of each joins the ipsilateral ductus deferens to form the ejaculatory duct.

Vesicula seminalis (seminal vesicle) in a median sagittal section of the male urogenital organs.

umbilical vesicle  the pear-shaped expansion of the mammalian yolk sac growing out into the cavity of the chorion, joined to the midgut by the yolk stalk.

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optic vesicle

n.

See ocular vesicle.

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optic vesicle,

an early embryonic outgrowth from the ventrolateral wall of the forebrain. Its cells develop into the retina and optic nerve of the eye. Also called ophthalmic vesicle.

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optic

of or pertaining to the eye.

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optic chiasma

see optic chiasm.

optic cortex

see visual cortex.

optic cup activity

see intraretinal space.

optic disk

the disk in the fundus of the eye marking the point at which the optic nerve enters; it is accompanied by blood vessels, is oval, light in color and the blind spot of the retina.

optic nerve

the second cranial nerve; it is purely sensory and is concerned with carrying impulses for the sense of sight. The rods and cones of the retina are connected with the optic nerve which leaves the eye slightly to the nasal side of the center of the retina. The point at which the optic nerve leaves the eye is called the blind spot because there are no rods and cones in this area. The optic nerve passes through the optic foramen of the skull and into the cranial cavity. It then passes backward and undergoes a division; those nerve fibers leading from the nasal side of the retina cross to the opposite side in the optic chiasma while those from the temporal side continue to the thalamus uncrossed. The nerve tracts proceeding backward from the optic chiasm, pass around the cerebral peduncle, and dividing into a lateral and medial root, which end in the superior colliculus and lateral geniculate body, respectively. After synapsing in the thalamus the neurons convey visual impulses to the occipital lobe of the brain.

Injury to the nerve leads to partial or complete loss of sight on the opposite side. Commonly bilateral.

optic nerve aplasia

an uncommon congenital anomaly, most frequently seen in Collie dogs; affected animals are blind from birth. Hypovitaminosis A and prenatal infection with bovine virus diarrhea are possible causes.

optic nerve inflammation

optic neuritis.

optic primordia

the eyes begin in the embryo as a pair of shallow optic grooves on each side of the developing forebrain. The grooves form optic vesicles which invaginate to form a double-walled optic cup.

optic radiation

fibers from the lateral geniculate body entering the occipital cortex.

optic stalk

the evagination from the neural tube of the developing embryo which develops the optic cup at its extremity; the stalk persists as the optic nerve.

optic sulcus

see optic groove.

optic vesicle

the initial evagination from the neural tube which gives rise to the optic cup and the optic stalk.