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
7.35-7.45
•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.