Zusammenfassung der Ressource
Homeostasis
- Thermoregulation
- Controlled by the
Hypothalamus
- contains
receptors which
are sensitive to
blood tempreture
in brain
- When change is sensed it causes
a response in the Dermis
- When too hot:
- Erector
muscles
relax so
hairs lie
flat
- Sweat
evaporates to
transfer heat
- Vasodilation
- blood vessels widen so more blood
flows near the surface
- When too cold:
- Erector muscles
contract so hairs
stand up to trap a
layer of air
- vasoconstriction
- The blood vessels narrow so less
blood can flow near the surface so
less heat is lost
- Osmoregulation
- sending signals to
the brain carrying
information about
water content in
blood
- The brain processes the information and
sends signals to the kidneys regulating the
water in the urine.
- The signal is a hormone produced by the pituitary gland in
the brain. The blood carries the hormone to the kidneys.
- water content of the blood it high
less hormone is released.
- less hormone means more water passes through the
kidneys.
- Kidneys produce more urine
- water content of the blood is too low, more
hormone is released
- more hormone means less water passes through
- kidneys produce a small volume of urine
- Blood Glucose
- This is controlled to provide cells with a constant supply of energy. The blood
sugar level is controlled by the release and storage of glucose, which is in turn
controlled by a hormone called insulin
- Glucose too high
- insulin secreted into the blood
- liver converts glucose into
glycogen
- Glucose level goes
down
- Glucose too low
- insulin not secreted into the blood
- liver does not convert glucose into
glycogen
- The normal level of glucose
in the blood is about 90mg
per 10cm3 of blood
- The pancreas releases glucagon when sugar levels
fall This causes the cells in the liver to turn
glycogen back into glucose which can then be
released into the blood.