Lecture Notes 1. Organ Systems in Review Integumentary Musculoskeletal Respiratory Digestive Urinary Reproductive Circulatory Nervous

Transcription

1 Lecture Notes 1 Chapter 1 Introduction to Physiology Physiology is an integrative science Function and mechanism Themes in physiology Homeostasis Control systems and homeostasis The science of physiology Physiology Is an Integrative Science Integration of function across many levels of organization Complex systems have emergent properties Moving Beyond the Genome Genomics Study of all of the genomes of an organism Human Genome Project Proteomics Study of all of the proteins of an organism The Physiome Project Molecular, cellular, and physiological information Translational research 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 Organization of life The cell is the smallest unit of structure capable of carrying out all life processes Atoms, molecules, cells, tissues, organs, organ systems, and organisms Organ Systems in Review Integumentary Musculoskeletal Respiratory Digestive Urinary Reproductive Circulatory Nervous

2 Endocrine Immune Mapping Organizational tool for relationships and processes Schematic diagram of structure and function Atoms, molecules, cells, tissues, and organs Flow charts Diagram processes in sequence 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. Themes in Physiology Structure and function are closely related Molecular interactions Compartmentation Living organisms need energy Information flow coordinates body function Homeostasis maintains internal stability Homeostasis Regulation of the body s internal environment Keeping internal environment stable Interaction between Outside world Extracellular fluid Intracellular fluid Homeostasis External or internal change Loss of homeostasis Sensed by organism Physiological attempt to correct Dynamic steady state Not the same as equilibrium

3 Homeostasis Successful compensation Homeostasis reestablished Failure to compensate Disease Study of failure to compensate is pathophysiology Control Systems and Homeostasis Regulated variables are kept within normal range by control mechanisms Keeps near set point, or optimum value Control systems local and reflex Input signal Integrating center Output signal Control Systems and Homeostasis Local control Reflex control Long-distance pathway Uses nervous and/or endocrine systems Response loop Stimulus, sensor, input signal, integrating center, output signal, target, response Feedback loop Negative feedback stabilizes variable Positive feedback reinforces stimulus Feedforward control anticipates change Biological Rhythms Regulated variables create repeating patterns Daily circadian rhythms Acclimatization occurs naturally Acclimation in a laboratory setting Experimental Design Hypothesis Independent and dependent variables Experimental controls Data collection and replications Difference between models and theories Interpretation of Human Experiments Difficult to interpret results Genetic and environmental variability Crossover studies Placebo effect and nocebo effect

4 Blind, double-blind studies, and double-blind crossover studies Ethics of humans as test subjects Experimental Design Formats Longitudinal studies versus cross-sectional studies Prospective versus retrospective studies Meta-analysis Physiology is an integrative science Function and mechanism Themes in physiology Homeostasis Control systems and homeostasis The science of physiology Chapter 2 Molecular Interactions Molecules and bonds Noncovalent interactions Protein interactions Biomolecules Organic molecules contain carbon Biomolecules are associated with living organisms Carbohydrates, lipids, proteins, nucleotides Conjugated proteins (e.g., lipoproteins; blood transport molecules) Glycosylated molecules (e.g., glycoproteins, glycolipids) in cell membranes Polymers made of repeating unit Molecules and Bonds Bonds link atoms Bonds store and transfer energy Molecules versus weaker interactions Functional Groups Combinations of elements that occur frequently in biological molecules Move along molecules as a single unit Four Important Roles of Electrons Covalent bonds Ions High-energy electrons

5 Free radicals Types of Chemical Bonds Covalent Bonds Covalent bonds Share a pair of electrons Single, double, and triple bonds Polar versus nonpolar molecules Types of Chemical Bonds Ionic Bonds Ionic bonds Atoms gain or lose electrons Opposite charges attract Ions Ions are charged atoms Cations Lost electrons Positively charged (+) Anions Gained electrons Negatively charged ( ) Types of Chemical Bonds Hydrogen and Van der Waals Hydrogen bonds Weak and partial Water surface tension Van der Waals forces Weak and nonspecific Aqueous Solutions Aqueous Water-based Solution Solute dissolves in solvent Solubility Ease of dissolving Hydrophilic Hydrophobic Molecular Shape and Function Molecular bonds determine shape Shape is closely related to function Proteins have the most complex and varied shapes Secondary structures: alpha-helix and beta-pleated sheets Fibrous proteins Tertiary structure

6 Globular proteins Disulfide bonds (S-S) Hydrogen Ion Concentration (ph) Free H + can change a molecule s shape ph Measure of the concentration of free H + Acid Contributes to H + solution Buffer moderates changes in ph Soluble Protein Enzymes Membrane transporters Signal molecules Receptors Binding proteins Immunoglobulins Regulatory proteins Protein Interactions Binding Noncovalent bonds with other molecules Occurs at binding site Go to a state of equilibrium Ligands Substrates Proteins are specific about bonding Molecular complementarity Induced-fit model Affinity Dissociation Constant Indicates Affinity Dissociation constant (K d ) Competitors Agonists Multiple Factors Affect Protein Binding Isoforms Activation Proteolytic activation (lysis) Cofactors Modulation/modulators Chemical modulators Competitive versus irreversible antagonists Allosteric versus covalent modulators

7 Physical factors Body Regulates the Amount of Protein in Cells Up-regulation Down-regulation Reaction Rate Can Reach a Maximum Concentration of ligand Maximum reaction rate Saturation Molecules and bonds Noncovalent interactions Protein interactions