Infectious diseases are caused by microorganisms such as viruses, bacteria, fungi or parasites and can spread between individuals. 1  Infectious diseases are caused by microorganisms such as viruses, bacteria, fungi or parasites. 2  Microorganisms that cause disease are collectively called pathogens.
The Abdominopelvic Cavity The abdominopelvic cavity extends from the diaphragm to the pelvis. It is subdivided into a superior abdominal cavity and an inferior pelvic cavity (Figure 1-11a,c). The abdominopelvic cavity contains the peritoneal cavity, a chamber lined by a serous membrane known as the peritoneum.
Light micrograph of Paramecium (Paramecium multimicronuleatum), a ciliate protozoan, with oral groove, food vacuoles, nucleus (left edge) and cilia. Paramecium are found mainly in stagnant ponds, feeding on bacteria and plant particles. They have a permanent mouth called an oral grove.