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Temperature
too low
Temperature
too high
Independently, list some additional bodily functions that must be balanced to prevent harm from either too
little or too much of either. Then discuss homeostasis with a partner in order to exchange ideas.
7.2 Reading #1:
Homeostatic Process
Homeostasis, also known as the "steady state," is the continual
process by which animal
organs and organ systems adapt to internal and external changes. These adjustments could be made
to the blood's
calcium or glucose levels, or to the temperature outside.
Homeostasis
means to
maintain dynamic equilibrium in the body. It is dynamic because it continuously makes adjustments
in response to changes that the body's systems go through. Because bodily functions are maintained
within predetermined ranges, it is equilibrium. Even a seemingly inactive animal is able to maintain
this homeostatic balance.
The goal of homeostasis is the maintenance of equilibrium around a point or value called a
set point
. The body's systems will typically try to return to this point even though there are typical
fluctuations from the set point. A stimulus is a change in the internal or external environment that is
detected
by a receptor, and the system's response is to move the deviation
parameter closer to the set
point. For instance, modifications are made to cool the animal if its body gets too warm. After eating,
if blood glucose levels rise, adjustments are made to get the nutrients into the tissues that need them
or to store them for later use.
Control of Homeostasis
An animal's
environment changes, so an adjustment must be made.
The receptor detects a
change in the environment and signals it to the control center, which is typically the brain. The control
center then produces a response and signals it to an effector. A muscle (which contracts or relaxes)
or a gland (which secretes) is an effector. Negative feedback loops keep homeostasis in check.
Positive feedback loops may be necessary for life to exist even though they actually push the organism
further away from homeostasis. Homeostasis is controlled by the nervous and endocrine system of
mammals

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