4. Tissues & Organ Systems

What is the role of the effector in a negative feedback loop?

An increase in blood solute concentration, as measured by the osmoreceptors of the hypothalamus, indicates a net loss of water in the body. The hypothalamus responds by both stimulating a thirst response and releasing antidiuretic hormone. Antidiuretic hormone directs the kidneys to recover more water during urine production. In this case, what two parts of a feedback loop are occurring in the hypothalamus?

When the body temperature rises above the set point, how will the body respond?

While waiting for a bus on a very cold winter day, your body temperature starts to drop. Specialized cells in your preoptic area (POA) of the hypothalamus register a drop in your internal body temperature. Cells in the hypothalamus integrate that information and activate nerve cells that cause muscles around the blood vessels leading to the skin and extremities to contract. When these muscles contract, less blood flows to the skin and extremities. What is the effector in this scenario?