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OBJECTIVES
After studying this chapter, you should be able to:
Define functional units used in measuring physiological properties.
Define pH and buffering.
Understand electrolytes and define diffusion, osmosis, and tonicity.
Define and explain the significance of resting membrane potential.
Understand in general terms the basic building blocks of the cell (eg, nucleotides, amino acids, carbohydrates, and fatty acids) to cell metabolism, proliferation, and function.
Understand higher-order structures of the basic building blocks of the cell (eg, DNA, RNA, proteins, and lipids) to cell replication, proliferation, and signal transduction.
Understand the basic contributions of the basic building blocks of the cell to its structure, function, and energy balance.
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In unicellular organisms, all vital processes occur in a single cell. As the evolution of multicellular organisms progressed, various cell groups organized into tissues, and organs have taken over particular functions. In humans and other vertebrate animals, there are a number of specialized collections of cells that consist in organ systems serving for different functions. For example, a gastrointestinal system to digest and absorb food; a respiratory system to take up O2 and eliminate CO2; a urinary system to remove wastes; a cardiovascular system to distribute nutrients, O2, and the products of metabolism; a reproductive system to perpetuate the species; and nervous and endocrine systems to coordinate and integrate the functions of the other systems. This book is concerned with the way these systems function and the way each contributes to the functions of the body as a whole. This first chapter lays a foundation for the discussion of these organ systems with a review of basic biophysical and biochemical principles at the cellular level and the introduction of the molecular building blocks that contribute to cell physiological function within these organ systems.
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THE BODY AS ORGANIZED “SOLUTIONS”
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In the average young adult male, 18% of the body weight is protein and related substances, 7% is mineral, and 15% is fat. The remaining 60% is water. The distribution of the body water is shown in Figure 1–1A.
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