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.
AIDS was first reported in the United States in 1981 and has since become a major worldwide epidemic. AIDS is the most advanced stage of infection caused by HIV. The names HIV and AIDS can be confusing because both terms describe the same disease. But most people who are HIV positive do not have AIDS.