Transcript III. So What Do These Systems Have To Do With

Body Systems and Cells:
Temperature Regulation
I. How do living things stay alive in
extreme temperatures?
• One of the characteristics of living things is that
they can maintain stable internal conditions. This
is called homeostasis.
• One type of balance that organisms must
maintain is temperature balance.
Why do you think organisms would want to
maintain stable temperatures? Why not
just let your body be any temperature?
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I. How do living things stay alive in
extreme temperatures?
• Some organisms are ectotherms –
they get heat from their external
environment.
ECTO = outside THERM = heat
• Some organisms are endotherms –
they make their own heat through
metabolism (chemical reactions)
and other ways such as shivering.
ENDO = inside
THERM = heat
Some Ways Living Things Carry Out
Thermoregulation:
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Dogs – panting
Squirrels – laying on cool surfaces
Lizards – sitting in the sun
Cows – finding shade
Kangaroos – licking arms
Humans – sweating and
vasodilation
Kangaroo licking its arms to
cool down on a very hot day
II. How Do Humans Maintain
Homeostasis in Extreme Temperatures?
• Two body systems that are involved in
thermoregulation are the circulatory system and
the nervous system.
II. How Do Humans Maintain
Homeostasis in Extreme Temperatures?
CIRCULATORY SYSTEM:
• The circulatory system
includes the heart, veins,
arteries, and capillaries.
These last three are called
blood vessels. The
specialized function of this
body system is to pump
blood to cells in the body.
Blood carries oxygen,
carbon dioxide, and
nutrients to and from cells.
II. How Do Humans Maintain
Homeostasis in Extreme Temperatures?
CIRCULATORY SYSTEM:
• Red blood cells are specialized
cells that have iron atoms in
them. Oxygen diffuses
through lung tissues into
blood vessels and binds to
(sticks to) the iron in the red
blood cell. Then when the red
blood cell reaches an area that
has a low amount of oxygen,
the oxygen diffuses into the
cells that need it.
II. How Do Humans Maintain
Homeostasis in Extreme Temperatures?
How does the structure
(shape and make-up) of
a red blood cell match its
function (its job)?
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II. How Do Humans Maintain
Homeostasis in Extreme Temperatures?
NERVOUS SYSTEM:
• The nervous system
includes the brain, spinal
cord, and nerves. The
specialized function of
this body system is to
send and receive
messages through the
body with electrical
currents and chemical
signals.
II. How Do Humans Maintain
Homeostasis in Extreme Temperatures?
NERVOUS SYSTEM:
• Nerves are specialized
cells that have many
protein pumps. The
pumps can pump + or ions into our out of the
cell. When these ions
flow back to equilibrium,
they create an electric
current.
II. How Do Humans Maintain
Homeostasis in Extreme Temperatures?
NERVOUS SYSTEM:
• Nerves also have
dendrites and axon
terminals, extensions
that let them
communicate with many
other nerve cells to
create complex thoughts.
Video
II. How Do Humans Maintain
Homeostasis in Extreme Temperatures?
How does the structure of
a nerve cell match its
function?
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III. So What Do These Systems Have To
Do With Temperature Regulation?
• A part of the brain called the hypothalamus is
constantly monitoring body temperature. (For
humans, it should be 98.6°F) If the body is too hot
or too cold, the brain sends an electrochemical
signal to other parts of the body.
III. So What Do These Systems Have To
Do With Temperature Regulation?
• TOO HOT  Brain sends a signal telling veins to
dilate (get larger). This allows heat to leave the
blood more quickly.
III. So What Do These Systems Have To
Do With Temperature Regulation?
• TOO HOT  Brain sends a signal telling skin to
start sweating. This allows hot water molecules to
leave the skin, making the skin cooler.
III. So What Do These Systems Have To
Do With Temperature Regulation?
• TOO COLD  Brain
sends a signal telling
veins to constrict (get
smaller). This allows
the body to conserve
(save) heat.
III. So What Do These Systems Have To
Do With Temperature Regulation?
• TOO COLD  Brain
sends a signal telling
muscles to shiver
(shake). This creates
heat, raising the
internal temperature.