Feedback Loops
Maintaining Homeostasis
NEGATIVE FEEDBACK
Balancing Calcium
When there isn't enough calcium in the blood, parathyroid glands release parathyroid hormones that tell special osteoclasts to take calcium from other places in the body, like bones, and give it to the blood. When calcium is low, the body stops giving calcium to to other places and adds more to the blood.
POSITIVE FEEDBACK
Blood Clotting
When a vessel gets damaged, platelets begin to attach to the open wound where blood is already pouring out and attract even more platelets. They build up and release chemicals to form a clot that closes he wound. When platelets are initially added, it eventually draws more platelets.