optical vesicle

(noun)

The eyes begin to develop as a pair of diverticula from the lateral aspects of the forebrain. These diverticula make their appearance before the closure of the anterior end of the neural tube; after the closure of the tube they are known as the optic vesicles.

Related Terms

  • mandibular arch
  • mesencephalon

Examples of optical vesicle in the following topics:

  • Development of Vision

    • First, an outpocketing of the neural tube occurs, creating optic vesicles.
    • Development of the optic vesicles starts in the three-week embryo from a progressively deepening groove in the neural plate called the optic sulcus.
    • The optic vesicles come into contact with the epithelium and induce the epidermis.
    • Further induction by the chordamesoderm forms a protrusion: the optic vesicle.
    • After the closure of the tube they are known as the optic vesicles.
  • Fourth Week of Development

    • At the end of the fourth week the yolk sac presents the appearance of a small pear-shaped vesicle (the umbilical vesicle) opening into the digestive tube by a long narrow tube, the vitelline duct.
    • The optical vesicle (which will eventually become the optic nerve, retina, and iris) forms at the basal plate of the prosencephalon.
    • A white circle represents the area of the optical vesicle.
  • Embryonic Development of the Brain

    • The optical vesicle (which will eventually become the optic nerve, retina and iris) forms at the basal plate of the prosencephalon.
  • Embryonic Development

    • The prosencephalon further goes on to develop into the telencephalon (the forebrain or cerebrum) and the diencephalon (the optic vesicles and hypothalamus).
  • Optic (II) Nerve

    • The optic nerve is also known as cranial nerve II.
    • The optic nerve is the second of twelve paired cranial nerves.
    • As a consequence, optic nerve damage produces irreversible blindness.
    • The optic nerve leaves the orbit, which is also known as an eye socket, via the optic canal, running posteromedially toward the optic chiasm, where there is a partial decussation (crossing) of fibers from the nasal visual fields of both eyes.
    • An illustration of the brain highlighting the optic nerve and optic tract.
  • Transcytosis

    • Transcytosis, or vesicle transport, is one of three mechanisms that facilitate capillary exchange, along with diffusion and bulk flow.
    • Substances are transported through the endothelial cells themselves within vesicles.
    • The substance to be transported is endocytosed by the endothelial cell into a lipid vesicle which moves through the cell and is then exocytosed to the other side.
    • Vesicles are capable of merging, allowing for their contents to mix, and can be transported directly to specific organs or tissues.
  • Orbits

    • To the rear of the orbit, the optic foramen opens into the optical canal through which the optic nerve and ophthalmic artery pass.
    • Finally, the sphenoid bone forms the posterior wall of the orbit and also contributes to the formation of the optic canal.
  • Accessory Sex Glands

    • The seminal vesicles secrete a significant proportion of the fluid that ultimately becomes semen.
    • Seminal vesicle fluid is alkaline, resulting in human semen with a mildly alkaline pH.
    • The vesicle produces a substance that causes the semen to become sticky after ejaculation, thought to help keep the semen near the cervix.
    • Seminal vesicle fluid is expelled under sympathetic contraction of the muscularis muscle coat.
    • Prostate with seminal vesicles and seminal ducts, viewed from the front and above, including the urethra, seminal vesicle, vas deferens, ampulla, ejaculatory duct, and isthmus.
  • Yolk Sac Development

    • At the end of the fourth week, the yolk sac has the appearance of a small, pear-shaped vesicle (umbilical vesicle) opening into the digestive tube by a long, narrow tube, the vitelline duct.
    • The vesicle can be seen in the afterbirth as a small, somewhat oval-shaped body whose diameter varies from 1 mm to 5 mm.
    • In the meantime Heuser's membrane, located on the opposite pole of the developing vesicle, starts its upward proliferation and meets the hypoblast.
  • Semen

    • Semen is produced and originates from the seminal vesicles, located in the pelvis.
    • During the process of ejaculation, sperm pass through the ejaculatory ducts and mix with fluids from the seminal vesicle, the prostate, and the bulbourethral glands to form semen.
    • The seminal vesicles produce a yellowish viscous fluid rich in fructose, amino acids, and other substances that make up about 70% of human semen.
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