9. c. Students know how feedback loops in the nervous and endocrine systems regulate conditions in the body.
9. i.* Students know how hormones (including digestive, reproductive, osmoregulatory) provide internal feedback mechanisms for homeostasis at the cellular level and in whole organisms.
Feedback loops are how the nervous system uses the endocrine system to regulate body conditions.
The presence or absence of hormones in blood brought to the brain by the circulatory system will trigger an attempt to regulate conditions in the body.
The hormone leptin, which fat cells produce as they become filled with storage reserves.
Leptin is carried by the blood to the brain, where it normally acts to stop hunger
An example of negative feedback. When fat reserves diminish, the concentration of leptin decreases, a phenomenon that in turn causes the appetite center in the brain to start the hunger stimulus and activate the urge to eat.
Hormones work with the Nervous System
For ex-ample, in the digestive system, where insulin released from the pancreas into the blood regulates the uptake of glucose by muscle cells.
The pituitary master gland produces growth hormone for controlling height.