CHIASMA Definition & Meaning

chiasma

Also ��·��

[kahy-az-muh]

Phonetic (Standard)IPA

noun

plural

chiasmas, chiasmata

Anatomy.��a crossing or decussation, as that of the optic nerves at the base of the brain.
Cell Biology.��a point of overlap of paired chromatids at which fusion and exchange of genetic material take place during prophase of meiosis.

chiasma

/ kaɪˈæzmə, ˈkaɪæzəm /

noun

cytology the cross-shaped connection produced by the crossing over of pairing chromosomes during meiosis
anatomy the crossing over of two parts or structures, such as the fibres of the optic nerves in the brain

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Other 51�Թ� Forms

chiasmal adjective
chiasmic adjective
chiasmatic adjective
��ˈ�� adjective

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51�Թ� History and Origins

Origin of chiasma¹

1830–40; < Greek: crosspiece of wood, cross-bandage, equivalent to chi chi ¹ + -asma noun suffix

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51�Թ� History and Origins

Origin of chiasma¹

C19: from Greek khiasma wooden crosspiece, from khiazein to mark with an X, from khi _chi ¹

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Example Sentences

Examples have not been reviewed.

Pressure on the optic chiasma, for example by a tumour of the pituitary body, is associated with bilateral temporal hemianopsia.

From

The movement follows the course of the optic nerve, traverses the chiasma, goes along the fascia, passes the internal capsule, and finally arrives at the visual centres of the occipital region.

From

They have an arterial cone and bulb, spiral intestinal valve, and the optic nerves united by a chiasma.

From

We know that they are directly connected by fibres that arch round through the chiasma.

From

chiaroscuro chiasmatypy

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