acrosomal vesicle

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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acrosomal vesicle

n.

A vesicle derived from the Golgi apparatus during spermiogenesis; its membrane adheres to the nuclear envelope of the sperm and, together with the acrosomal granule within the vesicle, spreads in a thin layer over the pole of the nucleus to form the acrosomal cap.