Memmler’s A&P Chap 2 Chemistry, matter, and life

Chemistry p20 Study of composition and properties of matter. Matter is anything that takes up space. Elements: substances that make up matter. Atoms: subunits of elements Common chemical elements in the body: – Oxygen O2 – Carbon C – Hydrogen H – Nitrogen N – Calcium Ca – Potassium K – Sodium Na – Iron Fe

Atoms p20 Atomic structure: – Nucleus Protons Neutrons – Orbiting around the nucleus of the atom in energy levels are electrons.

Compounds p21 Substances composed of two or more different elements are called compounds The picture is of a molecule of water.

Mixtures p22 – Solutions: mixture formed when one substance dissolves in another Solvent: liquid part Solute: solid part Aqueous solution: solution that has water as the solvent Example: saline – Suspensions: non-uniform mixture. The particles will settle out of the solvent. Example: milk of magnesia – Colloids: molecules do not dissolve, but remain evenly distributed in the suspending material Example: cytosol

Electrolytes p23 Electrolytes: ionically bonded substances separate into charged particles when they go into solution Note: in practice, the term electrolytes is also used to refer to the ions themselves in body fluids. Examples: Na+, K+, Cl-, Ca++

pH scale p24-26 Physiologic normal pH for blood and body fluids is pH less then 7.35 is called acidosis pH higher than 7.45 is called alkalosis Buffers are chemicals that prevent rapid changes in H+ ion concentrations.

Organic compounds p27 Contain carbon Main types of organic compounds: carbohydrates: monosaccharide example: glucose lipids: (fats): glycerol + fatty acid example: triglycerides, steroids, cholesterol proteins: amino acids Nitrogen is provided in the diet in proteins.

Enzymes p28-30 Enzymes are catalysts: increase the speed of a chemical reaction without being changed or used up by the reaction. Names of enzymes end with –ase.