ABSTRACT
This chapter discusses the cell physiology. Cell membranes are a single layer of phospholipid, interspersed with proteins and cholesterol. Mitochondria produce adenosine triphosphate, the type of energy which cells use. There are essentially two mechanisms for cell death: apoptosis and necrosis. Damaged tissue releases pro-inflammatory cytokines, which trigger a "cytokine cascade" of vasoactive chemicals, which: vasodilate, increase capillary leak, and activate other defences. Infection initiates early release of acute phase proteins, including fibrinogen, alpha-1 protinase inhibitor, C-reactive protein and serum amyloid associated protein to assist phagocytosis. Lack of oxygen and the generation of oxygen radicals are key mechanisms in cell necrosis. Oxygen metabolism occurs intracellularly, inevitably releasing some radicals. The few radicals normally produced are destroyed by antioxidants, such as vitamin E, vitamin C, and albumin. Most critical illnesses originate and progress at cellular level; macroscopic symptoms are accumulations of microscopic problems.
