Introduction to Animal Body
Systems
Essential Questions
1. Describe how animal body systems are
organized.
2. Give an example of how form fits function in
animal body systems.
3. Describe how and why all organisms are
“open systems.”
Structural Organization of Animal
Bodies
• Parts of the body at
each level work
together to perform a
specific function
• Levels of Organization:
–
–
–
–
–
Cells
Tissues
Organs
Organ systems
Organism
Form Fits Function
• At each level, the
structure of each
component fits its specific
function
• Examples:
– The shape of a nerve cell
allows it to send signals
– The layers of epithelial
tissue create a protective
barrier
– The structure of the heart
allows it pump blood
Tissues
• Specialized cells are
organized into different
tissues
• Each tissue type
performs a different
function
Organs
• Organs are structures
that perform a specific
function in the body
• Organs are made up of
many different
interacting tissues
Organ Systems
• Organs systems are
groups of organs that
work together to
perform the functions
of the body
Organ Systems Covered This Year
Exchanges with the External
Environment
• Every organism is an
open system
– Chemicals & energy are
continuously exchanged
with the environment
– Nutrients & oxygen must
enter every cell
– Waste & carbon dioxide
must exit every cell
Exchanges the Human Body
• Organ systems in
humans that exchange
materials with the
external environment:
– Digestive system
– Respiratory system
– Urinary system
• These are all connected
by the circulatory
system!
Adaptations for Exchange
• Complex animals have
evolved structures that
are folded or branched
– Increases the surface
area for exchange
• Examples:
– Lungs
– Brain
– Blood vessels
Essential Questions
1. Describe how animal body systems are
organized.
2. Give an example of how form fits function in
animal body systems.
3. Describe how and why all organisms are
“open systems.”