Stress and Function
Physiology is the study of the functional activities of the living or-ganism and its parts. Pathophysiology is the study of disordered function of the body. Each different body system performs spe-cific functions to sustain optimal life for the organism. Mecha-nisms for adjusting internal conditions promote the normal steady state of the organism and ultimately its survival. These mecha-nisms are compensatory in nature and work to restore balance in the body. An example of this restorative effort is the development of rapid breathing (hyperpnea) after intense exercise in an at-tempt to compensate for an oxygen deficit and excess lactic acid accumulated in the muscle tissue.
Pathophysiologic processes result when cellular injury occurs at such a rapid rate that the body’s compensatory mechanisms can no longer make the adaptive changes necessary to remain healthy. An example of a pathophysiologic change is the development of heart failure: the body reacts by retaining sodium and water and increasing venous pressure, which worsens the condition. These pathophysiologic mechanisms give rise to signs that are observed by the patient, nurse, or other health care provider, or symptoms that are reported by the patient. These observations, plus a sound knowledge of physiologic and pathophysiologic processes, can as-sist in determining the existence of a problem and can guide the nurse in planning the appropriate course of action.