annulus(redirected from Annular region)
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annulus[an´u-lus] (pl. an´nuli) (L.)
alternate spelling of anulus.
annulus/an·nu·lus/ (an´u-lus) pl. an´nuli [L.] anulus.
n. pl. annu·luses or annu·li (-lī′)
1. A ringlike figure, part, structure, or marking, such as a growth ring on the scale of a fish.
a. A ring or group of thick-walled cells around the sporangia of many ferns that functions in spore release.
b. The ringlike remains of a broken partial veil, found around the stipes of certain mushrooms.
annulusAny ring-like structure (e.g., mitral valve annulus).
annulusAny ring-like structure.
- the ring of cells in the moss or fern capsule which splits to allow the liberation of spores.
- a ring of tissue surrounding the stalk in the fruiting bodies of the BASIDIOMYCOTA fungi.
pl. annuli, anuli [L.] a small ring or encircling structure.
a ring of Purkinje cells around the right A-V orifice that serves the myocardium and valves locally and also serves as an alternative connection between the atria and the ventricles.
the circular pad which connects the tympanic membrane to the external acoustic meatus.
1. four fibrous rings at the base of the heart to which the myocardium is attached, one around each A-V orifice and one each around the aorta and the pulmonary artery.
2. the intervertebral disks consist of a soft central pulpy nucleus and a peripheral annulus fibrosus.
the iris consists of two rings, an inner smooth annulus iridus minoris, and an outer plicated part, the annulus iridis major.
the ring of skin marking the entrance to the cavity of the prepuce.
a roll of connective tissue on the inside of the sclera at the corneoscleral junction.
a small ring condenses around the proximal centriole of the spermatid.
the ring through which the peritoneal cavity connects with the cavity of the vaginal tunic.