Feedback (+/-)

True or false: Negative feedback loops amplify changes to the set point of a system.

False.

True or false: Positive feedback loops reverse changes to the set point of a system.

False.

If blood glucose levels rise, the body may secrete insulin which will lower the blood glucose levels. What type of feedback loop is this?

Negative feedback loop.

What is the definition of a negative feedback loop?

Negative feedback occurs when some function of the output of a system, process, or mechanism is fed back in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by other disturbances.

Homeostasis involves which type of feedback?

Negative feedback.

The body senses that there is too much substance X in the blood. The brain sends a message to organ Y to metabolize substance X. The brain keeps sending this signal until the levels of substance X is within normal limits. What type of feedback loop is this?

Negative feedback.

The hypothalamus of a human responds to temperature fluctuations and responds accordingly. If the temperature drops, the body shivers to bring up the temperature and if it is too warm, the body will sweat to cool down due to evaporation. What type of feedback loop is this?

Negative.

This is an example of which type of feedback: If the numbers of prey decreases, then some predators will starve, and their numbers will decrease.

Negative.

What is a positive feedback loop?

Positive feedback is a process that occurs in a feedback loop in which the effects of a small disturbance on a system include an increase in the magnitude of the perturbation.

Another example of feedback is seen in childbirth, where stretching of the uterus triggers the secretion of a hormone , oxytocin, which stimulates uterine contractions and speeds up labor. What type of feedback loop is this?

Positive feedback.

When an apple on a tree ripens, it releases ethylene which signals the apples around it to ripen and do the same. This is an example of which feedback?

Positive.

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. This is a type of which feedback?

Positive.

What is homeostasis?

The process by which organisms maintain a relatively stable internal environment.

True or false: Negative feedback reverses changes in a system, while positive feedback amplifies changes in a system.

True.

True or false: Positive feedback loops move the system away from its starting state.

True.