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Maintenance of homeostasis
requires communication . . . what
are the body’s two
“communication” or control
systems?
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Variable – what is being regulated
Stimulus –something that produces a change
in the variable and causes it to move away
from its ‘normal range’
Homeostasis is the body’s ability to maintain
a relatively stable internal environment even
though the outside world is constantly
changing.
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Why is homeostasis important?
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What are some examples of homeostasis?
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Nervous System (Fast acting)
Sends messages using nerves
Endocrine System (Slow acting)
Sends messages using hormones
3 Parts:
1. Receptor (sensor): alerts the
control center when it detects
changes in the variable
2. Control Center: receives, analyzes
and responds to information about the
variable
3. Effector: carries out the control
center’s response
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Moves the body back towards ‘normal’ when
a change is detected.
(It moves variables that have strayed from
normal back in the opposite or negative
direction towards where they should be)
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These are the most common control systems
found in the body
Systems that work to increase a change in a
variable (instead of moving it back toward
where it was originally).
These systems are rare in the body.
They tend to control infrequent events that
occur explosively and do not require
continuous adjustments.
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