a general term for cavity or chamber which may have specific meaning in reference certain organs or sites in the body. The antrum of the stomach (gastric antrum) is a portion before the outlet which is lined by mucosa which does not produce acid. The paranasal sinuses can be referred to as the frontal antrum, ethmoid antrum, and maxillary antrum.
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... in the centre is oocyte, the purple cells surrounds are follicle cells a.k.a. granulosa cells a.k.a granulocytes. The white part is follicle's antrum (room) which contains follicle's liquor, a viscous fluid that is rich in steroid reproductive hormones, especially androgens and estrogens.
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