|The immune system is composed of organs, tissues, cells, and chemical messengers that interact to protect the body from external invaders and its own internally altered cells. The chemical messengers arecytokines which are secreted by cells of the immune system that direct immune cellular interactions. Lymphocytes (leukocytes that are categorized as either B cells or T cells) secrete lymphokines. Monocytes and macrophages secrete monokines. Interleukins are a type of cytokine that send messages among leukocytes to direct protective action. The best way to understand this system is through the body's various levels of defense. The goal of pathogens is to breach these levels to enter the body, reproduce, and subsequently exploit healthy tissue, causing harm. The immune system's task is to stop them.
Scholarly journal is a peer-reviewed journal in which scholarship relating to a particular academic discipline is published. Scholarly journals serve as forums for the introduction and presentation for scrutiny of new research, and the critique of existing research. Content typically takes the form of articles presenting original research, review articles, and book reviews. The term Scholarly journal applies to scholarly publications in all fields; this article discusses the aspects common to all academic field journals.