The body requires a precise atmospheric pressure to maintain its gases in solution and to facilitate respiration-the intake of oxygen and the release of carbon dioxide. Although the body can respond to high temperatures by sweating and to low temperatures by shivering and increased fuel consumption, long-term exposure to extreme heat and cold is not compatible with survival. Humans cannot survive for more than a few minutes without oxygen, for more than several days without water, and for more than several weeks without carbohydrates, lipids, proteins, vitamins, and minerals. These processes include: organization, in terms of the maintenance of essential body boundaries metabolism, including energy transfer via anabolic and catabolic reactions responsiveness movement and growth, differentiation, reproduction, and renewal. They occur continuously to build, maintain, and sustain life. Most processes that occur in the human body are not consciously controlled. Therefore, molecules combine to form cells, cells combine to form tissues, tissues combine to form organs, organs combine to form organ systems, and organ systems combine to form organisms. Higher levels of organization are built from lower levels. These include the chemical, cellular, tissue, organ, organ system, and the organism level. Life processes of the human body are maintained at several levels of structural organization. 1.2 Structural Organization of the Human Body The two disciplines are typically studied together because form and function are closely related in all living things. It is difficult to study structure (anatomy) without knowledge of function (physiology). Physiology explains how the structures of the body work Human physiology is the scientific study of the chemistry and physics of the structures of the body. In the past, anatomy has primarily been studied via observing injuries, and later by the dissection of anatomical structures of cadavers, but in the past century,Ĭomputer-assisted imaging techniques have allowed clinicians to look inside the living body. Human anatomy is the scientific study of the body’s structures.