How do you maintain
a steady body temperature when you're
exposed to ice packs, or hot water bottles? Healthy Body temperature
is 37 degrees Celsius, or 98.6 degrees Fahrenheit. I need to keep a steady
temperature near 98.6 degrees Fahrenheit, or else crucial
molecules in my body will change shape and stop
working, and I'll die. Homeostasis is the
scientific term for my body's ability to
maintain its proper equilibrium temperature. But what if I'm exposed
to steaming hot water, or freezing cold ice? How does my body maintain its
equilibrium temperature then? Let's see. I'll cover myself
with ice packs, and see how my body reacts. Five cold minutes later, let
me check my body temperature. Sure enough, it's still near
normal body temperature, homeostasis in action. Within a degree or so 98.6
is still considered normal. And despite how cold I
feel, I haven't actually gotten any colder. How did my body do this? It made me feel cold, and
want to wear myself up by shivering, little muscle
movements that generate heat. See how pale my arm looks? After noticing the cold, my body
directed by blood to my core, and less to my skin
and extremities. My arm quickly loses heat
to the cold environment, but the temperature stays
constant in my core, which is thicker, so it loses less
heat to the environment. I also get goosebumps,
where my hair stands on end, creating an insulating
layer like the jacket my body wisher I were wearing. So my body uses a lot of tools
to keep my temperature up. When my body senses
that it's cold, homeostasis mechanisms make
me shiver, draw blood away from my skin, and
give me goosebumps. These make me warmer, so my
core temperature isn't changed. My body uses some of the
opposite tools to cool down. It directs blood to the
surface to cool down, making me a bit pink. It needs to resort to
more extreme measures if I want to be active in the
heat, because moving my muscles uses energy and lets off
heat, sort of like shivering to keep warm in the cold. But in this case, my body
needs to counteract the warmth that the movement causes. My body makes me feel
exhausted, urging me to stop running in
place, but that's not enough if I'm excited to be
running for some reason. It also makes me sweat. In order to get the energy
to evaporate into the air, sweat pulls heat from my body,
and this helps me cool down. Not all animals have as
effective sweat glands as people do, so
people can endure longer periods of
intense activity than many other animals. When I got warm,
homeostasis mechanisms let my blood move near
the surface of my skin, and made me sweat,
so I got cooler. There are other forms of
homeostasis to regulate things besides temperature. For example, when your blood
pressure drops suddenly, which can happen if
you stand up suddenly, your blood vessels constrict,
which brings your blood pressure up to normal. Also, if your blood sugar rises,
which can happen after eating, your pancreas releases insulin
to lower your blood sugar back to normal. Diabetes is the disease that
affects your body's ability to maintain blood
sugar homeostasis. In general, homeostasis
is when our bodies recognize a slight drift
from healthy conditions, and counteract that drift by
nudging us back to equilibrium.