Ascus

An ascus (plural asci; from Greek ἀσκός ảskós 'skin bag') is the sexual spore-bearing cell produced in ascomycete fungi. Asci usually contain eight ascospores, produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or species can occur in numbers of one (e.g. Monosporascus cannonballus), two, four, or multiples of four. In a few cases, the ascospores can bud off conidia that may fill the asci (e.g. Tympanis) with hundreds of conidia, or the ascospores may fragment, e.g. some Cordyceps, also filling the asci with smaller cells. Ascospores are nonmotile, usually single celled, but not infrequently may be coenocytic (lacking a septum), and in some cases coenocytic in multiple planes. Mitotic divisions within the developing spores populate each resulting cell in septate ascospores with nuclei. The term ocular chamber, or oculus, refers to the epiplasm (the portion of cytoplasm not used in ascospore formation) that is surrounded by the "bourrelet" (the thickened tissue near the top of the ascus).

Ascus (bryozoa)

The ascus is a diagnostic morphological feature of the bryozoan suborder Ascophora (hence the name of the suborder). It is a water-filled sac of frontal membrane opening (ascopore) at or near the zooid orifice. It functions as a hydrostatic system by allowing water into the space below the inflexible, calcified frontal wall (covering their whole frontal surface apart from the orifice) when the zooid everts its polypide (feeding tentacles) by muscles pulling the frontal membrane inwards (non-ascophoran cheilostomes do not need this structure as their frontal wall is not calcified and thus flexible).

References

Pap test

The Papanicolaou test (abbreviated as Pap test, known earlier as Pap smear, cervical smear, or smear test) is a method of cervical screening used to detect potentially pre-cancerous and cancerous processes in the cervix (opening of the uterus or womb). Abnormal findings are often followed up by more sensitive diagnostic procedures, and, if warranted, interventions that aim to prevent progression to cervical cancer. The test was invented by and named after the prominent Greek doctor Georgios Papanikolaou.

A Pap smear is performed by opening the vaginal canal with a speculum, then collecting cells at the outer opening of the cervix at the transformation zone (where the outer squamous cervical cells meet the inner glandular endocervical cells). The collected cells are examined under a microscope to look for abnormalities. The test aims to detect potentially pre-cancerous changes (called cervical intraepithelial neoplasia (CIN) or cervical dysplasia; the squamous intraepithelial lesion system (SIL) is also used to describe abnormalities), which are caused human papillomaviruses, a sexually transmitted a DNA virus. The test remains an effective, widely used method for early detection of pre-cancer and cervical cancer. While the test may also detect infections and abnormalities in the endocervix and endometrium, it is not designed to do so.