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Physical agents such as heat or radiation can damage a cell by literally cooking or coagulating their contents. Impaired nutrient supply, such as lack of oxygen or glucose, or impaired production of adenosine triphosphate (ATP) may deprive the cell of essential materials needed to survive. [3] Metabolic: Hypoxia and ischemia; Chemical agents
Cell signaling is a fundamental property of all cellular life in prokaryotes and eukaryotes. Typically, the signaling process involves three components: the signal, the receptor, and the effector. [citation needed] In biology, signals are mostly chemical in nature, but can also be physical cues such as pressure, voltage, temperature, or light
The epithelial surfaces form a physical barrier that is impermeable to most infectious agents, acting as the first line of defense against invading organisms. [3] Desquamation (shedding) of skin epithelium also helps remove bacteria and other infectious agents that have adhered to the epithelial surface.
These physicochemical agents can be exogenous in origin, and include ionizing and non-ionizing radiation, the diet, lifestyle factors, pollution, and xenobiotics. They may damage the macromolecules directly, or indirectly e.g., some xenobiotic substances require metabolism of the xenobiotic to produce a chemically reactive metabolite which can ...
The term "biological target" is frequently used in pharmaceutical research to describe the native protein in the body whose activity is modified by a drug resulting in a specific effect, which may be a desirable therapeutic effect or an unwanted adverse effect. In this context, the biological target is often referred to as a drug target.
Due to their size, cytokines cannot cross the lipid bilayer of cells to enter the cytoplasm and therefore typically exert their functions by interacting with specific cytokine receptors on the target cell surface. Cytokines have been shown to be involved in autocrine, paracrine and endocrine signaling as immunomodulating agents.
Exotoxin activity can be separated into specific cytotoxic activity or broad cytotoxic activity based on whether the toxin targets specific cell types or various cell types and tissues, respectively. Lethal toxins refers to the group of toxins that are the obvious agents responsible for death associated with the infection.
Cytotoxic T cells are powerful agents of cellular immunity. Cellular immunity , also known as cell-mediated immunity , is an immune response that does not rely on the production of antibodies . Rather, cell-mediated immunity is the activation of phagocytes , antigen-specific cytotoxic T-lymphocytes , and the release of various cytokines in ...