Mesoderm lining the coelom forms mesothelium. Separation of Peritoneal and Pleural Cavities: In the adult, peritoneal and pleural cavities are separated by the diaphragm. The diaphragm isformed by a septum transversum, paired pleuroperitoneal folds, and somatic mesoderm.
HIV Myth 2: 'HIV and AIDS Are the Same Thing'. Absolutely not. HIV is the virus that infects a person and attacks the immune system. AIDS is the disease that develops later in people with HIV that remain untreated or don't respond to treatment.
What Are HIV and AIDS? HIV (human immunodeficiency virus) is a virus that most likely mutated decades ago from a virus that infected chimpanzees to one that infects humans. It began to spread beyond the African continent in the late 1970s and is now endemic worldwide.