Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
1. a small bladder or sac containing liquid.
2. a small circumscribed elevation of the epidermis containing a serous fluid; a small blister.
allantoic vesicle the internal hollow portion of the allantois.
auditory vesicle a detached ovoid sac formed by closure of the auditory pit in the early embryo, from which the percipient parts of the inner ear develop.
brain v's the five divisions of the closed neural tube in the developing embryo, including the telencephalon, diencephalon, mesencephalon, metencephalon, and myelencephalon.
brain v's, primary the three earlier subdivisions of the embryonic neural tube, including the forebrain, midbrain, and hindbrain.
brain v's, secondary the four brain vesicles formed by specialization of the forebrain and of the hindbrain in later embryonic development.
chorionic vesicle the chorion of a mammal.
encephalic v's brain vesicles.
germinal vesicle the fluid-filled nucleus of an oocyte toward the end of prophase of its meiotic division.
lens vesicle a vesicle formed from the lens pit of the embryo, developing into the crystalline lens.
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 auditory vesicle.
seminal vesicle paired sacculated pouches attached to the posterior urinary bladder; the duct of each joins the ipsilateral ductus deferens to form the ejaculatory duct.
umbilical vesicle the pear-shaped expansion of the yolk sac growing out into the cavity of the chorion, joined to the midgut by the yolk stalk.
in the embryo, one of the paired evaginations from the ventrolateral walls of the forebrain from which the sensory and pigment layers of the retina develop.
Either of the paired evaginations of the embryonic forebrain from which the optic nerve and retina develop.
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.
optic vesiclean embryological structure formed by the outpushing of the forebrain of vertebrates, which eventually gives rise to the optic cup.
of or pertaining to the eye.
see optic chiasm.
see visual cortex.
optic cup activity
see intraretinal space.
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.
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
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.
fibers from the lateral geniculate body entering the occipital cortex.
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.
see optic groove.
the initial evagination from the neural tube which gives rise to the optic cup and the optic stalk.