Zusammenfassung der Ressource
B3 - Homeostasis
- Homeostasis is the maintenance of a constant internal envrionment
- Six thing that need to be controlled
- Body temperature, Water content
(too high/low, too much move
into/out of cells and damage them,
Ion content( same thing could
damage cells), blood sugar levels
- Two waste products
- CO2 product of
respiration. Toxic
qualities need to be
removed. Urea
made from excess
amino acids.
- Body temperature must be carefully controlled.
Enzymes in a human body work best around 37C.
Otherwise the enzymes wont work properly and
some really important reactions could be disrupted
- There is a
thermoregulatory centre in
the brain which acts as a
personal thermostat. It
contains receptors that are
sensitive to the
temperature of the blood
flowing through the brain.
- It also
receives
impulses
from the
skin, giving
information
about skin
temperature.
- When you're too hot, hairs lie flat, sweat
is produced by sweat glands and
evaporates from skin, removing heat.
Blood vessels supplying the skin dilate so
more blood flows close to the surface of
the skin. This means it is easier for heat
to be transferred from the blood to the
environment.
- When you're too cold, hairs stand up to trap
an insulating layer of air, no sweat is
produces,blood vessels supplying skin
capillaries constrict to close off the skin's
blood supply, you shiver. This needs
respiration which releases some energy to
warm the body.