Mark the following statements as true or false. If a statement...

Question

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

The effects of negative feedback loops are amplified to create an escalating response.

Accepted Answer

Hi, everyone. Let's take a look at our next question. Which of the following is an example of a negative feedback mechanism. A amplification of labor contractions, B, narrowing of surface blood vessels when body temperature drops, C increasing the release of prolactin during lactation or D all of the above. So let's think about what a negative feedback mechanism is and then evaluate these answer choices. Remembering we have that option of all of the above and negative feedback. A process or a change happens that results in something that opposes that initial change or inhibits that initial process. So let's look at these choices and decide which one shows that characteristic choice A says amplification of labor contractions. Well, even before we start to think about what's going on here, we have a clue in the word amplification. Negative feedback mechanisms oppose or inhibit the change or process that's happening. But we have something that amplifies the event. So our event is the uterus starts to contract to expel the baby. And we have these contractions being amplified as labor goes on. The contractions become stronger and more frequent. So therefore, this is not a negative feedback mechanism but positive feedback. Because the event that happens, the labor contractions become stronger and more frequent is amplifying the initial event, contracting of uterus, these contractions increase and become faster. So that's positive feedback. And therefore, is not our answer. We can also cross out choice B all of the above since we've already ruled out one answer. Now let's look at choice B narrowing of surface blood vessels when body temperature drops. So what's our initial event or change the body temperature drops? So this is our initial event. And what happens as a result of dropping body temperature is that the blood vessels near the surface of the skin contract or are constricted. This means less blood flow goes to the skin surface, which means less heat is lost on the skin surface and more heat is retained in the body's core. What does that cause? Well, it causes the temperature, body's temperature to stop dropping, perhaps even rise but at the very least stop dropping. So the result of the initial event being constriction of the blood vessels caused something to happen, the body temperature to stop dropping, that opposed the initial change of the body temperature dropping. That can definitely be a bit tricky to sort through. When you're talking about opposing a change like this, it can be easier to recognize a negative feedback loop when it involves something like the product of this enzymatic reaction comes and inhibits the enzymatic reaction from taking place that can be a little easier to understand as negative feedback. But in this case, here, we always just have to focus on what is the initial event? What is the initial change? And is the result inhibiting or opposing the initial change? Then it's a negative feedback. So choice B is our answer as an example of negative feedback to be thorough. Let's look at choice C increasing the release of prolactin during lactation. Well, again, here as in a we have a clue just in the word increasing, something that's going to increase an event, it's probably going to involve positive feedback. And indeed, this does prolactin causes the breasts to release milk. As the milk lets down, the baby's suckling increases as suckling increases, more prolactin is released, more milk is let down. You can see how this is a positive feedback event. And again, we focus on the fact the initial event is release of prolactin and it causes more prolactin to be released due to the chain of events that happens. Interestingly, this is how the body causes a supply and demand relationship when breastfeeding. Because the more the baby suckles because the baby's hungrier, the baby's growing, the more milk is produced, the less the baby suckles, the less milk is produced. So that's how that positive feedback loop helps fine tune that system of lactation. But again, this is positive feedback. So not our answer. So cross out, I see and again, an example of a negative feedback mechanism is choice b narrowing of surface blood vessels when body temperature drops, see you in the next video.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
The effects of negative feedback loops are amplified to create an escalating response.

Key Concepts

Negative Feedback Loops

Amplification in Feedback Mechanisms

Homeostasis

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