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Essentials of Human Anatomy & Physiology
Elaine N. Marieb
Seventh Edition
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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4 elements make up 96% of the human body
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Carbon
Hydrogen
Oxygen
Nitrogen
13 elements make up 99%+ of the body
◦ Know the major function of each
C.
HOPKINS CaFe
has Mighty good
NaCl
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Versions of elements
◦ Same # protons & electrons so chemical
properties are exactly the same but;
◦ Different # of neutrons so may be radioactive

Radioisotopes
◦ Used in diagnostics & treatments due to
radioactive properties
◦ Chosen based on
 Target tissue
 Shortest half life
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Read Medical Imaging: Illuminating the Body
◦ Study:
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How each image is different?
Why that is an advantage?
What are the disadvantages to each?
What is each type better at visualizing?
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When atoms combine, they form
Molecules/Compounds
◦ Type of bond formed is determined by
 Atoms involved in bond
 # of bonding electrons
◦ Polarity of bond formed is determined by
 Atoms involved in bond
 How atoms share/transfer electrons

Nonpolar
molecules
◦ Share electrons
equally
◦ Electrically balanced
◦ Symmetrical
geometry

Polar molecules
◦ Share electrons
unequally
◦ Asymmetrical
◦ Has + and –
charged poles
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Intermolecular bond
between polar
molecules
Hydrogen has partial
positive charge
Attracted to an
electronegative atom
on another molecule
“sticks” molecules
together
Responsible for 3-D
shape of important
molecules
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Strongest of intermolecular forces
Extremely important in determining the
properties of water and biological
molecules such as proteins
◦ Allows blood (mostly H2O) to absorb and transport
a large amount of nutrients
◦ DNA’s alpha helix shape is due to hydrogen bonds
between strands
Important to Know:
Do not contain carbon with hydrogen
Tend to be simpler compounds
Example: H2O (water)

High heat capacity
◦ Absorbs large amounts of heat energy BEFORE
changing temperature
◦ Assures body temperature homeostasis

High heat of vaporization
◦ Absorbs large amount of heat energy BEFORE
changing phase and carrying the heat away
◦ Efficient cooling mechanism

Polarity gives
excellent solvent
properties
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Hydration layers
Transport medium
Lubricant
Polarity allow water
to surround and
separate polar
compounds & small
molecules

Water is an important part of many chemical
reactions
◦ Dehydration synthesis
◦ Hydrolysis

The presence of water in fluids & tissues also
plays an important role in protection through
cushioning
◦ Cerebrospinal fluid
◦ Tissue fluid
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Consists of metal cation with nonmetal
anion to form an ionic compound - pH can
be anything
Easily dissociate/separate into ions in the
presence of water
Vital to many body functions - Function as
electrolytes to carry current in the body
◦ Nerve transmission
◦ Muscle contraction

Acids are compounds that increase the
presence of hydronium ions (H+)
◦ HCl, H2SO4, etc
◦ pH is below 7

Bases are compounds that increase the
presence of hydroxide ions (OH-)
◦ NaOH, NH3, etc
◦ pH is above 7
pH – a logarithmic scale
• Measures relative
concentration of hydronium
ions
• Scale runs from 0-14 with
each unit representing a
tenfold change in H+ conc.
• pH 7 = neutral
• pH below 7 = acidic
• pH above 7 = basic
Figure 2.11
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.25
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Combinations of acids & bases that allow
your body to resist large, abrupt (sudden)
changes in pH
This allows your body to maintain pH
homeostasis
If this buffer is overloaded, a disease process
will be initiated
Important to Know:
Contain carbon and hydrogen
Most are covalently bonded & complex
Example: C6H12O6 (glucose)
Important Organic Compounds
• Carbohydrates (contain CHO)
• 1-2% of body mass
• Classified according to size & solubility
• Larger size = decreased solubility and vice
versa
• Solubility is important for transport
& reactivity
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.26
Monosaccharides
• Monosaccharides – simple sugars
• Small size = greater solubility
• Simple sugars that body uses for immediate
energy
• Glucose, fructose, and galactose
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.26
Disaccharides
• Disaccharides
• two simple sugars joined by dehydration
synthesis
• Sucrose, maltose, and lactose
• All complex sugars MUST be broken down
into MONOSACCHARIDES for the body to
utilize in glycolysis and cellular respiration
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.26
 An
anabolic process by
which two molecules are
chemically joined through
the use of enzymes and a
loss of water
A
catabolic process by
which the bonds between
monomers are broken by
the enzyme and the
addition of water.
◦ Storage forms of sugars (cellular fuel & some
structural components)
◦ Starch
 Type of polysaccharide found in Plants
 Cellulose & lignin indigestible by humans
 Used for FIBER (drink lots of water!!)
◦ Glycogen
 Skeletal muscle and liver cells in animals
 Glycogen use: stored energy that is quickly
available
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If your blood sugar (glucose) gets too high:
◦ Your body stores it in your liver and skeletal
muscles as glycogen

If your blood sugar gets too low:
◦ Your body breaks down the glycogen and
releases glucose to your blood

Just another example of negative feedback
systems!
Or fat fat fat fat fat
Important Organic Compounds
• Intro to Lipids
• Non Polar organic compound
• Similar to carbs in that they contain
carbon, hydrogen, and oxygen BUT
• There is a greater C to H ratio – that is
what makes them more energy rich than
carbs
• There are 3 main types of fats
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.29
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KNOW THIS FACT:
Lipids are not soluble in water. This is
because water is polar and most lipids are
nonpolar.
Why are nonpolar substances unable to
dissolve in a polar substance such as water?
(can’t form hydrogen bonds so can’t be
surrounded or dissolved to become soluble)

Aka. - Triglycerides
◦ Most concentrated source of usable energy/fuel
◦ Found primarily in subcutaneous fat
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INSULATION (subcutaneous fat)
ENERGY STORAGE
CUSHIONING FOR INTERNAL ORGANS
ABSORPTION OF FAT SOLUBLE VITAMINS:
◦ ADEK
◦ THESE VITAMINS CANNOT BE ABSORBED UNLESS
THEY ARE DISSOLVED IN FAT
 Saturated
Fats –
◦ SINGLE C-C BONDS, straight,
pack closely together
◦ SOLID at room temp.
◦ ANIMAL FATS

Unsaturated Fats –
◦ DOUBLE C=C BONDS, Bent, can’t pack closely
together
◦ LIQUID at room temp
◦ PLANT FATS
Unsaturated fats are better than
saturated because the body can break
them down easier and so they are used
more quickly in the body’s metabolism.
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Produced when cis vegetable oils are heated.
Multiple heatings, such as a fast food fryer,
converts large quantities of cis to trans bonds
Concern: trans fatty acids are carcinogenic
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Complex
lipids
Phospho
portion is
polar
Lipid
portion is
non polar
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Important for
cell
membrane
repair and
construction
Also a
component
of nervous
tissue
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Hydrocarbon ring structures
Vital to homeostasis
Cholesterol, cortisol, and aldosterone
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Cholesterol is found in all ANIMAL tissue.
Plants do NOT contain cholesterol
◦ Cholesterol is the MOST IMPORTANT steroid since it
is essential for the manufacture of ALL other
steroids
◦ It also helps to STABILIZE your cell membranes.
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LIPOPROTEINS are molecules that help
transport lipids in the blood (since lipids are
NOT water soluble, they cannot circulate by
themselves)
HIGH DENSITY LIPOPROTEINS
◦ Transport excess cholesterol to liver for
breakdown
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LOW DENSITY LIPOPROTEINS
◦ Transport excess cholesterol to cells for storage
(can clog artery walls, etc.)
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YOU WANT YOUR HDL LEVEL TO BE HIGHER
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ADEK
Page 41 & 457
Toxicity: easier to OD on these than on water
soluble vitamins
◦ ADEK excesses are stored in your fat cells
◦ Other vitamins are excreted in the water based
urine
In charge of all your body functions
Important Organic Compounds
• Proteins
• Contain carbon, oxygen, hydrogen,
nitrogen, and sometimes sulfur
• 10-30% of body mass
• Wide variety of functions:
•Structural
•enzymes
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Consists of amino acids connected by peptide
bonds
Unique properties of each protein are
determined by
◦ Type of amino acid
◦ Sequence of amino acid

Proteins have a wide variety of functions.
These functions can be divided into 2
categories:
◦ STRUCTURAL: General Use is to support and
strengthen
◦ FUNCTIONAL: General use is to play crucial roles in
biological processes
◦ You do need to memorize these specific examples
in the notes. Proteins are VERY IMPORTANT!!!

Structural
◦ Use: Linear building
proteins
◦ Primary/secondary
structure
◦ Insoluble in water
◦ Not chemically
active
◦ Collagen, keratin,
elastin

Functional
◦ Use: Globular action
proteins
◦ Tertiary/quaternary
◦ Soluble in water
◦ Chemically active
◦ Antibodies,
hormones, most
enzymes (anything
ending in -ase),
hemoglobin

Keratin: component of hair, nails, and found
in skin – also helps waterproof your skin
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Hemoglobin –
Carries oxygen
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Levels of structural complexity
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Primary
Secondary
Tertiary
quaternary
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Function of proteins depend on their
structure
◦ Structure depends on H bonds
◦ Active site and substrate relationship crucial to
the function
◦ Shape of active site determines enzyme
specificity
◦ Know enzyme, active site, substrate definitions
& relationship to each other!!
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Substrate: the molecule that is affected by
the enzyme
Active site: place on the enzyme where the
reaction occurs
ONE ENZYME ACTS ON ONLY ONE
SUBSTRATE: VERY SPECIFIC !
Amylase breaks down amylose
Lactase breaks down lactose
 Caused
by excesses in
temperature & pH – here is
what happens (know this!)
◦Disrupts H bonds
◦Structure/active site is lost
◦Function is lost

Enzymes can act as a catalyst
◦ A molecule that lowers ACTIVATION ENERGY
◦ This can increase a reaction’s speed (rate) up to
1010 times!!
◦ The enzyme is not changed at all by the chemical
reaction so can be reused over and over
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Chemical energy universally usable by all
cells
Contain just the right amount of energy for
most biochemical reactions
Reversible reaction - ATP is replenished
by oxidation of food fuels
Important Organic Compounds
• Deoxyribonucleic
acid (DNA) &
Ribonucleic Acid
(RNA)
• Collectively
provides
instructions to
make every
protein in the body
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 2.17c
Slide 2.36