AP BIOLOGY

Detailed explanation-1: -When you get cut, your skin cells release hormones that signal platelets to come and stop the bleeding. Platelets then release more hormones that signal even more platelets to help stop bleeding. The hormone signals continue until the cut is closed.

Detailed explanation-2: -Homeostasis typically involves negative feedback loops that counteract changes of various properties from their target values, known as set points. In contrast to negative feedback loops, positive feedback loops amplify their initiating stimuli, in other words, they move the system away from its starting state.

Detailed explanation-3: -When tissue is torn or injured, a chemical is released. This chemical causes platelets in the blood to activate. Once these platelets have activated, they release a chemical which signals more platelets to activate, until the wound is clotted. Figure 4: The process of wound clotting is a positive feedback loop.

Detailed explanation-4: -If the calcium in your blood decreases below homeostasis levels, a gland in the brain will sense to decrease and send a chemical message to your bones. Your bones will release calcium into the blood, bringing blood calcium levels back up.