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Homeostasis and Responce (Homeostasis and Body temperature: (Why is…
Homeostasis and Responce
Homeostasis and Body temperature:
Why is Homeostasis Important?
Control systems may involve:
Chemical
responses using
hormones
Responses using
nerves
What is Homeostasis?
It is the regulation of internal conditions of a
cell
or
organisms
in response to internal and external changes.
Homeostasis is important because it keeps conditions constant for
enzyme action
and
cell functions
.
Homeostasis includes the control of:
Water and ion levels
Blood glucose concentration.
Body temperature
Control Systems
:
All control system include:
Cells called
receptors
, which detect stimulus (changes in the environment)
Coordination centres which receive and process information from receptors. Such as...
Brain
Spinal cord
Pancreas
Effectors
which bring about responses that restore
optimum levels
. Such as...
Mussels
Glands
This type of control mechanism is called
negative feedback
:
The receptor detects a change in a stimulus.
The coordinating centre compares the stimulus to a set point
An effector then produces a response to correct and differences from the set point
Control of Body Temperature
:
Human body temperature should be kept at around
37C
This gives an optimum temperature for enzymes to work.
The
thermostatically
centre in the brain:
Monitors and controls body temperature.
has receptors that monitor the temperature of the blood flowing through the brain.
receives information (impulses) from temperatures receptors in the skin.
If the body temperature is
too high
:
blood vessels widen, directing more blood to the surface of the skin - this is called...
Vasodilation
More
sweat
is produced from the sweat glands and evaporates thus cooling the skin.
Both of these mechanisms cause a transfer of energy from the the skin to the environment.
If the body temperature is
too low
:
Blood vessels
narrow
, directing blood away from the surface of the skin - this is called...
Vasoconstriction
.
Sweating stops
Skeletal mussels uncontrollably contract and relax quickly (
shiver
), which transfers more heat to the blood.