STUDY AND REVIEW 1: HOMEOSTASIS: A FRAMEWORK FOR HUMAN PHYSIOLOGY STUDY AND REVIEW 1.1 ■ Physiology: study of the functions of the body parts ■ Pathophysiology: study of disease states (physiological dysfunction) Review Question: Distinguish between anatomy, physiology, and pathophysiology. How are they related? STUDY AND REVIEW 1.2 ■ Cells: simplest structural units into which a complex multicellular organism can be divided and still retain the functions characteristic of life ■ Cell differentiation: formation of four general types of specialized cells  Muscle cells: generate the mechanical activities that produce force and movement; 3 types include skeletal, cardiac, and smooth muscle cells  Neurons: initiate and conduct electrical signals  Epithelial cells: form barriers and selectively secrete and absorb ions and organic molecules; basolateral surface rests on a basement membrane  Connective-tissue cells: connect, anchor, and support the structures of the body; form the extracellular matrix, which consists of fibers such as collagen and elastin ■ Tissues: aggregates of differentiated cells with similar properties; correspond to the four general types of specialized cells ■ Organs: composed of two or more of the four kinds of tissues  Many organs contain multiple, small, similar functional units. ■ Organ system: group of organs that perform an overall function Review Question: It is a simplification to refer