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Physiology and the Principles of Physiology What is a physiological system? Matter + Energy Matter Occupies space -Solid, liquid, gas In human solid = bone, muscle, skin liquid = blood, saliva, urine gas = air breathed Energy Capacity to do work 1. Kinetic = energy used to produce work 2. Potential = stored energy, not currently being used to produce work. A physiological system must have both matter and energy. Forms of Energy a. Chemical--stored in chemical bonds; concentration differences b. Electrical--charged particles; ions c. Mechanical--directly moving object d. Radiant--travels in waves e. Thermal--molecular movement Composition of Matter 1. Atoms a. Nucleus 1) Protons: +charge 2) Neutrons: 0 charge b. Electrons: -charge Atomic Number Number of protons of nucleus 1H = hydrogen 2He = helium Neutral atom; protons = electrons Mass Number Sum of masses of protons and neutrons Hydrogen = 1proton 0 neutron = mass# = 1 Helium = 2 p 2 n = mass# = 4 Elements -Elements are substances that cannot be broken down into simpler substances (Ex: H, C, O) -The number of protons, neutrons, and electrons differs between elements Combining of Elements 1. Molecule--2 or more atoms of the SAME element If elements are the same, then have molecule of that element. Molecular O2 vs elemental O 2. Compound--2 or more different elements NaCl, H2O Breakage of bonds--provide energy to move matter Mixtures – 3 forms 1) Solutions- Homogenous mixtures of 2 or more substances a. Solvent = substance in greatest quantity (H2O) b. Solute = substance in smaller quantity (ions, proteins, carbohydrates, etc.) These systems also contain matter, energy Concentrations of Solutions 1) Percent--parts/hundred parts 10% solution NaCl = 10 p NaCl/100 p H20 2) Molarity--moles/liter 1 mole of any element/cmpd = molecular weight (sum of atomic weights) in grams. C6H12O6 C 6x12.011= 72.066 H 12x1.008= 12.096 O 6x15.999= 95.994 Total: 180.156g or 1M 1M solution = 1M of a chemical substance in 1L of solvent 1M of any substance always contains the exact # of solute particles... Avogadro’s Number: 6.02x10^23 1M Glucose: 180g 1M Water: 18g 1M Methane: 16g …You will always have 6.02x10^23 molecules of that substance 3) Osmolarity/Osmolality Number of particles within a solution Membrane-semipermeable Important in controlling movement of fluids between body compartments. Differences in osmolality between compartments serves as energy. Mixtures contd… 2) Colloids--solute is large, but dissolvable, particles scatter light. (Jello, cell cytoplasm) 3) Suspensions--mixtures of solutions where the solute will settle out unless you repeatedly shake it. (Sand in water, blood cells in plasma) Chemical Bonds Combination of atoms via electron sharing Electron shell--electrons exist in different regions around nucleus. Each shell = different level of energy Close to nucleus = lower energy. Each shell can hold a specific # of electron… Lowest energy level accepts 2 electrons. 2nd level accepts 8 3rd level accepts 18 Valence shell--outermost shell of that given atom. Electrons here can be reactive, and can form chemical bonds with one another. If the valence shell is “full”, then the atom is not reactive. “Full” = 2 electrons in lowest energy level. 8 electrons in 2nd level If the valence shell is not full, then the atom is reactive These atoms are very prevalent in physiology Energy is transferred during reactions between these atoms. Bonds are formed Types of Chemical Bonds 1) Ionic bonds--one atom donates electron to the electron shell of another atom Anion (acceptor) and cation (donor) End result is stable valences for both 2) Covalent bond-electrons are shared between two atoms -Electron sharing-equal or unequal a) non-polar--equal sharing (CH4) b) polar--unequal sharing (H2O) 3) Hydrogen bonds-attractions between slightly charged molecules such as water Chemical Reactions 1. Equations 4H + C → CH4 2. a. b. c. Patterns of chemical reactions Synthesis A + B → AB Decomposition AB → A + B Exchange AB + C → AC + B Exergonic--give off energy Ex: Breakdown of a glucose molecule Endergonic--absorb energy Ex: Formation of ATP Reversibility of Chemical Reactions A+B → C A+B Effectors of Chemical Reactions a. Temperature--higher, faster rate b. Particle size--larger or smaller c. Concentration--greater, faster rate d. Catalysts 1) enzymes--faster rate ↔ C Part II- Biochemistry In physiological systems we find inorganic and organic compounds that: -are reactive and interactive -store and release energy -are structurally strong -are catalysts Inorganic Compounds 1) Water a. Heat properties-absorb or lose heat b. Solvent properties-polarity c. Reactivity 2) Salts--ionic compounds with cations other than H+ and anions other than OH- Electrolytes--ions; conduct current in solution NaCl, KCl 3) Acids and Bases a. Acids 1) Sour 2) Dissolve in water (release protons) 3) Concentration of protons determine acidity Ex: HCl b. Bases 1) Bitter 2) Dissolve in water (release OH-) 3) Take on protons Ex: HCO3-, NH3 pH-- acid/base H+ concentration logarithmic scale pH is tightly regulated--why? Organic Compounds 1. Carbohydrates Carbon + Hydrogen + Oxygen 1:2:1 1) Monosaccharide--one chain or ring; ribose, glucose, fructose 2) Disaccharides--two rings joined; glucose + fructose = sucrose 3) Polysaccharides--three or more sugars— starch, cellulose, glycogen Carbohydrate function--fuel 2) Lipids Carbon + Hydrogen + Oxygen--proportion of O is much lower than carbohydrates; also some Phosphorus Neutral fats--triglycerides 1) glycerol--3 carbon 2) fatty acids--long carbon chains a) saturated--no C-C double bonds b) unsaturated--at least one C=C double bonds Non-polar covalent bonds Phospholipids--one fatty acid chain replaced by phosphate group Steroids--flat, 4 hydrocarbon rings Cholesterol--membranes, bile salts, vitamin D and steroid hormones (estrogen, testosterone) 3) Proteins Carbon + Hydrogen + Oxygen + Nitrogen Amino acids-- building blocks; 20 Polarity varies Protein Structure 1) Primary structure--amino end of one amino acid joins with acid end of second amino acid. Forms peptide bond 2) Secondary structure--α-helix, β-sheet. Folding of protein due to amino acid chain arrangement 3) Tertiary structure--helix or sheet folds over itself 4) Quaternary structure-aggregation of 2 or more polypeptide chains. Hemoglobin 4) Nucleic Acids C, H, O, N, P 2 major classes: DNA--deoxyribonucleic acid; RNA--ribonucleic acid Structural units: nucleotides DNA 1) Location--nucleus & mitochondrion 2) Structure--double helix 3) Stability--stable 4) Function--template for protein synthesis 5) Elements-sugar: deoxyribose bases: A,T, C, G phosphate 6) Complementary bases; A:T; C:G RNA 1) Location--outside nucleus 2) Structure--single stranded 3) Stability--easily broken down 4) Function--protein synthesis; messenger (mRNA), ribosome (rRNA), amino acid carrier (tRNA) 5) Elements-a) sugar: ribose b) bases: A, G, C, U (no Thymine) 6) Complementary bases A:U, G:C Adenosine Triphosphate (ATP)--nucleotide with 3 additional phosphate groups Energy--main energy currency for body