2. Basic Chemistry


96% of the human body is composed of these elements

- Oxygen
- Carbon
- Hydrogen
- Nitrogen

Oxygen composes ______ of the human body.


Carbon composes _______ of the human body.


Hydrogen composes ______ of the human body.


Nitrogen composes _______ of the human body.


______ of body mass is made up of 9 other elements.


The 9 lesser elements of the human body:

- Sulfur
- Magnesium
- Iodine
- Iron
- Chlorine
- Calcium
- Sodium
- Potassium
- Phosphorus

Calcium (Ca) is found as...

salt in bones and teeth.

Calcium's ionic (Ca2+) form is required for...

muscle contraction, conduction of nerve impulses, and blood clotting.

Phosphorus (P) is part of...

calcium phosphate salts in bones and teeth.

Potassium (K) is necessary for...

conduction of nerve impulses and muscle contraction.

The major positive ion (cation) in cells.

Potassium (K)

Sulfur (S) is a component of ______.

proteins (particularly muscle proteins)

Sodium (Na) is important for...

water balance, conduction of nerve impulses, and muscle contraction.

A major positive ion (cation) found in extracellular fluids.

Sodium (Na)

The most abundant negative ion (anion) in extracellular fluids.

Chlorine (Cl)

_______ is present in bone and is also an important cofactor in a number of metabolic reactions.

Magnesium (Mg)

________ is needed to make functional thyroid hormones.

Iodine (I)

Iron is a component of...

hemoglobin and some enzymes.

Salts are ______ compounds held together by ______ bonds.

inorganic... ionic

What are electrolytes?

substances that conduct electrical current in solution.

All ions are ______.


Gastric juice pH

1.2 - 3.0 (very acidic)

Vaginal fluid pH

3.5 - 4.5 (moderately acidic)

Urine pH

4.6 - 8.0

Saliva pH


Arterial blood pH

7.35 - 7.45

Semen pH

7.2 - 7.6



Pancreatic juice pH

7.1 - 8.2

Bile pH

7.6 - 8.6