Nutrient
Substances in food that provide the raw materials and
energy the body needs to carry out all its essential processes.
calorie
The amount of energy needed to raise the temperature of
one gram of water by one degree Celsius.
carbohydrate
Energy-rich organic compound, such as a sugar or a
starch, that is made of the elements carbon, hydrogen, and oxygen.
glucose
A sugar that is the major source of energy for the
body�s cells.
fat
Energy-containing nutrients that are composed of carbon, oxygen, and hydrogen.
protein
Large organic molecule made of carbon, hydrogen,
oxygen, nitrogen, and sometimes sulfur.
amino acid
A small molecule that is linked chemically to other
amino acids to form proteins.
vitamin
Molecules that act as helpers in a variety of chemical
reactions within the body.
mineral
Nutrients that are needed by the body in small amounts
and are not made by living things.
digestion
The process by which the body breaks down food into
small nutrient molecules.
absorption
The process by which nutrient molecules pass through
the wall of the digestive system into the blood.
saliva
The fluid released when the mouth waters that plays an
important role in both mechanical and chemical digestion.
enzyme
A type of protein that speeds up a chemical reaction
in a living thing
epiglottis
A flap of tissue that seals off the windpipe and
prevents food from entering.
esophagus
A muscular tube that connects the mouth to the stomach
mucus
A thick, slippery substance produced by the body.
peristalsis
Involuntary waves of muscle contraction that
stomach
A J-shaped, muscular pouch located in the abdomen.
small intestine
The part of the digestive system in which most chemical
digestion takes place.
large intestine
The last section of the digestive system, where water
is absorbed into the bloodstream and the remaining material is
eliminated from the body.
liver
The largest organ in the body; it plays a role in
many body processes
bile
A substance produced by the liver that breaks up fat particles.
gallbladder
The organ that stores bile after it is produced by the liver.
pancreas
A triangular organ that lies between the stomach and
first part of the small intestine
villus
Tiny finger-shaped structures that cover the inner
surface of the small intestine and provide a large surface area
through which digested food is absorbed.
rectum
The end of the large intestine where waste material is
compressed into a solid form before being eliminated.
anus
The opening at the end of an organism�s digestive
system through which wastes exit.