Chapter 1 Introduction to Physiology About this Chapter

Chapter 1 Introduction to Physiology

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, organ systems, and organisms

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

Levels of Organization - Human

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

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. ”

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

Homeostasis • • • Most cells contact extracellular fluid Out out Out In External environment In in of 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 results in loss of homeostasis Organism attempts to compensate Compensation fails Illness or disease Compensation succeeds Wellness Figure 1 -4

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

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

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 -6 b