Chapter 3. Digestion and Absorption
: psychological desire to eat specific foods that arises from environmental stimuli
physiological process that prompts us to find and eat food that arises from internal
: breaking food into components small enough to be absorbed into the body
: the proves of taking substances into the interior of the body
Food Becomes Us
the smallest units of an element that still retain the properties of that element
: Substances that cannot be broken down into products with different
: Units of two or more atoms of the same or different elements chemically
: The smallest unit in living systems
: cells of similar structure and function (stomach has all the four)
: discrete structure of more than one tissue; perform a specialized function
-Organ System: a group of cooperative organs
What It Includes
What It Does
Brain, spinal cord, and
Responds to stimuli from the external and
internal environments; conducts impulses
to activate muscles and glands; integrates
activities of other systems.
Lungs, trachea, and air
Supplies the blood with oxygen and
removes carbon dioxide.
Kidneys and their
Eliminates wastes and regulates the
balance of water, electrolytes, and acid in
Testes, ovaries, and their
Heart and blood vessels
Transports blood, which carries oxygen,
nutrients, and wastes.
Lymph and lymph
structures, white blood cells
Defends against foreign invaders, picks up
fluid leaked from blood vessels, transports
Provides movement and structure.
Bones and joints
Protects and supports the body, provides a
framework for the muscles to use for
Pituitary, adrenal, thyroid,
pancreas, and other
Secretes hormones that regulate
processes such as growth, reproduction,
and nutrient use.
Skin, hair, nails, and sweat
Covers and protects the body; helps
control body temperature.
intestines, pancreas, liver,
Ingests and digests food, absorbs
nutrients into the blood, eliminates
unabsorbed food residues liver, and
gallbladder and other wastes.
Overview of Digestive System
Gastrointestinal tract (GI Tract)
: a 30 feet hollow tube from mouth to anus