Necessary Life Functions Metabolism—chemical reactions within the body Breaks down complex molecules into smaller ones Builds larger molecules from smaller ones Produces energy (ATP) Regulated by hormones Excretion Eliminates excreta (waste) from metabolic reactions Wastes may be removed in feces, or sweat Necessary Life Functions Reproduction Occurs on cellular or organismal level On cellular level—new cells are used for growth and repair On organismal level—the reproductive system handles the task Growth Increases cell size or body size (through increasing the number of cells) Hormones play a major role Survival Needs Nutrients Chemicals used for energy and cell building Include carbohydrates, proteins, lipids, vitamins, and minerals Oxygen Required for chemical reactions Made available by the cooperation of the respiratory and cardiovascular systems Survival Needs Water 60 to 80 percent of body weight Most abundant chemical in the human body Provides fluid base for body secretions and excretions Normal body temperature 37ºC (98.6ºF) Below this temperature, chemical reactions slow and stop Above this temperature, chemical reactions proceed too rapidly Survival Needs Atmospheric pressure Must be appropriate for gas exchange
Necessary Life Functions Metabolism—chemical reactions within the body Breaks down complex molecules into smaller ones Builds larger molecules from smaller ones Produces energy (ATP) Regulated by hormones Excretion Eliminates excreta (waste) from metabolic reactions Wastes may be removed in feces, or sweat Necessary Life Functions Reproduction Occurs on cellular or organismal level On cellular level—new cells are used for growth and repair On organismal level—the reproductive system handles the task Growth Increases cell size or body size (through increasing the number of cells) Hormones play a major role Survival Needs Nutrients Chemicals used for energy and cell building Include carbohydrates, proteins, lipids, vitamins, and minerals Oxygen Required for chemical reactions Made available by the cooperation of the respiratory and cardiovascular systems Survival Needs Water 60 to 80 percent of body weight Most abundant chemical in the human body Provides fluid base for body secretions and excretions Normal body temperature 37ºC (98.6ºF) Below this temperature, chemical reactions slow and stop Above this temperature, chemical reactions proceed too rapidly Survival Needs Atmospheric pressure Must be appropriate for gas exchange
ehap12-ch01-lecture-presentation.docx