Sinusitis is an inflammation of the sinuses. It is often caused by bacterial (germ) infection. Sometimes, viruses and fungi (molds) cause it. People with weak immune systems are more likely to develop bacterial or fungal sinus infection. Some people with allergies can have allergic fungal sinus infection. Acute sinus infection lasts three to eight weeks. A sinus infection lasting longer than eight weeks is considered chronic.
Define Upper stage. Upper stage synonyms, Upper stage pronunciation, Upper stage translation, English dictionary definition of Upper stage. n. A rocket composed of two or more propulsion units that fire in succession. Also called step rocket . Noun 1. multistage rocket - a rocket having two or...
During gastrulation, embryonic cells migrate through an opening within the embryo known as the blastocoele. As the gastrula forms, the remnants of the blastocoele shrink to eventually disappear completely. The opening into the gastrula is known as the blastopore. The inner cavity created by the infolding is known as the archenteron. The Way a cell turns to an embryo. Gastrulation is a phase early in the development of animal embryos, during which the morphology of the embryo is dramatically restructured by cell migration.