Homeostasis

Homeostasis is an organism's tendency to maintain internal equilibrium or stability in correspondence to the external environment.

Homeostasis

• regulated by feedback processes:
• positive feedback
• negative feedback

Positive Feedback
- a process that encourages physiological systems or amplifies the action of a system until a negative feedback takes over
-Ex: the body receives a positive feedback telling to form a clot and continue doing so when you get cut

Negative Feedback
-a process that happens when a bodily system has to slow down or stop
-once bleeding essentially stops body receives negative feedback to stop clotting

Positive

Negative

Coagulation

• process that prevents excessive bleeding when a blood vessel is injured
• involves proteins from platelets in the blood
• the enzyme thrombin
• & is ultimately controlled by the hypothalamus

Positive Feedback

Negative Feedback

Receptor

Control Center

Effector

Citation

• http://www.biology-online.org/dictionary/Homeostasis
• http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Clotting.html
• http://www.biology4kids.com/files/systems_regulation.html