Introduction to Physiology Chapter 1 Introduction to Physiology

Definition of physiology Review of organ systems Function and process About this Chapter Definition of physiology Review of organ systems Function and process Introduction to homeostasis Ideas in physiology Themes in physiology The science of physiology

Levels of Organization Physiology defined Study of the normal functioning of a living organism and its component parts Includes all its chemical and physical processes Literal “knowledge of nature” Aristole. Anatomy defined Study of structures Literal to dissect or take apart Organization of life The cell is the unit of life Cells, tissues, organs, organ systems, and organisms

Levels of Organization PHYSIOLOGY ECOLOGY CELL BIOLOGY MOLECULAR BIOLOGY CHEMISTRY Organ systems Populations of one species Ecosystem of different species Atoms Molecules Cells Tissues Organs Organisms Biosphere Figure 1-1

Levels of Organization - Human

Organ Systems in Review Protection from environmental hazards; temperature control Support, protection of soft tissues; mineral storage; blood formation Locomotion, support, heat production Directing immediate responses to stimuli, usually by coordinating the activities of other organ systems Directing long-term changes in the activities of other organ Internal transport of cells and dissolved materials, including nutrients, wastes, and gases Defense against infection and disease Delivery of air to sites where gas exchange can occur between the air and circulating blood Processing of food and absorption of organic nutrients, minerals, vitamins, and water Elimination of excess water, salts, and waste products; control of pH Production of sex cells and hormones Organ System Major Functions Integumentary system Skeletal Muscular Nervous Endocrine Cardiovascular Lymphatic Respiratory Digestive Urinary Reproductive Know Names, functions and major components NIRMCRUDLES Integumentary Musculoskeletal Respiratory Digestive Urinary Reproductive Circulatory / Cardiovascular Nervous Endocrine Lymphatic / Immune

Organ Systems in Review The integration between systems of the body Integumentary System Respiratory system Nervous system Circulatory system Endocrine system Digestive system Musculoskeletal system Urinary system Reproductive system Figure 1-2

Function versus Process Function explains the “why” Teleological approach Process or mechanism describes the “how” Mechanistic approach Red blood cell example “Because cells need oxygen and red blood cells bring it to them.” “Oxygen binds to hemoglobin molecules contained in the red blood cells.”

Adaptive significance of functions Keeping internal environment stable Homeostasis Adaptive significance of functions Keeping internal environment stable Cell Intracellular fluid Extracellular fluid Outside world

the internal environment Homeostasis Most cells contact extracellular fluid Out out Out In In in External environment of the body Material enters and leaves the body Material enters and leaves the body Intracellular fluid of most cells Extracellular fluid: the internal environment of the body Figure 1-3

Homeostasis and Controls External or internal change Loss of homeostasis Sensed by organism Physiological attempt to correct Negative feedback loop

Homeostasis and Controls Successful compensation Homeostasis reestablished Failure to compensate Illness Death Study of failure to compensate is pathophysiology

Homeostasis and Controls Organism in homeostasis External change Internal change Internal change results in loss of homeostasis Organism attempts to compensate Compensation fails Compensation succeeds Illness or disease Wellness Figure 1-4

Structure-function relationships Themes in Physiology Homeostasis Control systems Biological energy use Structure-function relationships Molecular interactions Mechanical properties of cells, tissues, and organs Communication Chemical and electrical signals

A simple control system Themes in Physiology A simple control system Input signal Output signal Controller Figure 1-5

Organizational tool for relationships and processes Concept Mapping Organizational tool for relationships and processes Schematic diagram of structure and function Cells, tissues, and organs Flow charts Diagram processes in sequence

Concept Mapping: Types of Maps Person working outside on a hot, dry day Loses body water by evaporation Body fluids become more concentrated Internal receptors sense change in internal concentration Thirst pathways stimulated Person seeks out and drinks water Water added to body fluids decreases their concentration (b) A process map, or flow chart Figure 1-6b