CK12 Life Science

organ system. Together, your heart, blood, and blood vessels form yourcardiovascular
system.

Organ Systems Work Together

Your body’s 12 organ systems are shown inTable16.1. Your organ systems do not work
alone in your body. They must all be able to work together to maintain homeostasis. For
example, when the men inFigure16.1jumped into the cold water, their integumentary
systems (skin, hair, nails), cardiovascular systems, muscular systems, and nervous systems
work quickly together to ensure the icy-cold water did not cause harm to their bodies. The
nervous system sent nerve messages from the skin to tell the cardiovascular system to reduce
the blood flow to the skin. Blood flow is then increased to the internal organs and large
muscles to help keep them warm and supply them with oxygen. The nervous system also
sent messages to the respiratory system to breathe faster. This allows for more oxygen to be
delivered by the blood to the muscular system which is shivering and moving about to keep
the body warm.Feedback loopsin the nervous and endocrine systems regulate conditions
in the body. A feedback loop is a path that leads from the initial generation of the signal
to the subsequent modification of the initial event. For example, the men that jumped into
the cold water do not need to continue to breathe faster and faster. Feedback loops return
the respiratory system to ”normal.” One of the most important functions of organ systems is
to provide cells with oxygen and nutrients and removes toxic waste products such as carbon
dioxide. A number of organ systems, including the cardiovascular and respiratory systems,
work together to do this.

Table 16.1:Major Organ Systems of the Human Body

Organ System Major Tissues

and Organs

Function Example

Cardiovascular Heart; blood

vessels; blood

Transports oxy-

gen, hormones

and nutrients to

the body cells,

and wastes and

carbon dioxide

away from cells