Question

1)Explain what a homeostatic mechanism is and how it is used to maintain conditions for life within the body, in language that a middle school student can understand?

2) Specifically address how homeostatic feedback loops are activated in response to changes in two of the major requirements for life of all organisms (water, heat, food, etc)?

3) Ensure that you discuss the difference between a negative and a positive feedback loop and give brief examples of each?

4) Give a possible explanation for why negative feedback mechanisms are used more within physiological systems than positive feedback loops?

Answer 1

1)Explain what a homeostatic mechanism is and how it is used to maintain

This adjusting of physiological systems within the body is called homeostatic regulation. Homeostatic regulation involves three parts or mechanisms: 1) the receptor, 2) the control center and 3) the effector. The receptor receives information that something in the environment is changing.

temperature, body fluid composition, blood sugar, gas concentrations, and blood pressure. Pressure by which the blood is pumped around the body is controlled by a homeostatic mechanism. maintain the body's body temperature.

2.how homeostatic feedback loops are activated in response to changes in two of the major requirements for life of all organisms.

Homeostasis is the tendency to resist change in order to maintain a stable, relatively constant internal environment.

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.

Homeostasis is the tendency to resist change in order to maintain a stable, relatively constant internal environment.

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.

ntroduction

What's the temperature in the room where you're sitting right now? My guess would be that it's not exactly 98.6\,^\circ\text F98.6

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F98, point, 6, degrees, start text, F, end text/ 37.0\,^\circ\text C37.0

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C37, point, 0, degrees, start text, C, end text. Yet, your body temperature is usually very close to this value. In fact, if your core body temperature doesn't stay within relatively narrow limits—from about 95\,^\circ\text F95

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F95, degrees, start text, F, end text/ 35\,^\circ\text C35

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C35, degrees, start text, C, end text to 107\,^\circ\text F107

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F107, degrees, start text, F, end text/ 41.7\,^\circ\text C41.7

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C41, point, 7, degrees, start text, C, end text—the results can be dangerous or even deadly.^1

1

start superscript, 1, end superscript

The tendency to maintain a stable, relatively constant internal environment is called homeostasis. The body maintains homeostasis for many factors in addition to temperature. For instance, the concentration of various ions in your blood must be kept steady, along with pH and the concentration of glucose. If these values get too high or low, you can end up getting very sick.

Homeostasis is maintained at many levels, not just the level of the whole body as it is for temperature. For instance, the stomach maintains a pH that's different from that of surrounding organs, and each individual cell maintains ion concentrations different from those of the surrounding fluid. Maintaining homeostasis at each level is key to maintaining the body's overall function.

So, how is homeostasis maintained? Let's answer this question by looking at some examples.

Maintaining homeostasis

Biological systems like those of your body are constantly being pushed away from their balance points. For instance, when you exercise, your muscles increase heat production, nudging your body temperature upward. Similarly, when you drink a glass of fruit juice, your blood glucose goes up. Homeostasis depends on the ability of your body to detect and oppose these changes.

Maintenance of homeostasis usually involves negative feedback loops. These loops act to oppose the stimulus, or cue, that triggers them. For example, if your body temperature is too high, a negative feedback loop will act to bring it back down towards the set point, or target value, of 98.6\,^\circ\text F98.6

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F98, point, 6, degrees, start text, F, end text/ 37.0\,^\circ\text C37.0

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C37, point, 0, degrees, start text, C, end text.

How does this work? First, high temperature will be detected by sensors—primarily nerve cells with endings in your skin and brain—and relayed to a temperature-regulatory control center in your brain. The control center will process the information and activate effectors—such as the sweat glands—whose job is to oppose the stimulus by bringing body temperature down.

Of course, body temperature doesn't just swing above its target value—it can also drop below this value. In general, homeostatic circuits usually involve at least two negative feedback loops:

One is activated when a parameter—like body temperature—is above the set point and is designed to bring it back down.

One is activated when the parameter is below the set point and is designed to bring it back up.

To make this idea more concrete, let's take a closer look at the opposing feedback loops that control body temperature.

Homeostatic responses in temperature regulation

If you get either too hot or too cold, sensors in the periphery and the brain tell the temperature regulation center of your brain—in a region called the hypothalamus—that your temperature has strayed from its set point.

For instance, if you’ve been exercising hard, your body temperature can rise above its set point, and you’ll need to activate mechanisms that cool you down. Blood flow to your skin increases to speed up heat loss into your surroundings, and you might also start sweating so the evaporation of sweat from your skin can help you cool off. Heavy breathing can also increase heat loss.

On the other hand, if you’re sitting in a cold room and aren’t dressed warmly, the temperature center in the brain will need to trigger responses that help warm you up. The blood flow to your skin decreases, and you might start shivering so that your muscles generate more heat. You may also get goose bumps—so that the hair on your body stands on end and traps a layer of air near your skin—and increase the release of hormones that act to increase heat production.

explanation for why negative feedback mechanisms are used more within physiological systems than positive feedback loops?

Positive feedback loops

Homeostatic circuits usually involve negative feedback loops. The hallmark of a negative feedback loop is that it counteracts a change, bringing the value of a parameter—such as temperature or blood sugar—back towards it set point.

Some biological systems, however, use positive feedback loops. Unlike negative feedback loops, positive feedback loops amplify the starting signal. Positive feedback loops are usually found in processes that need to be pushed to completion, not when the status quo needs to be maintained.

A positive feedback loop comes into play during childbirth. In childbirth, the baby's head presses on the cervix—the bottom of the uterus, through which the baby must emerge—and activates neurons to the brain. The neurons send a signal that leads to release of the hormone oxytocin from the pituitary gland.

Oxytocin increases uterine contractions, and thus pressure on the cervix. This causes the release of even more oxytocin and produces even stronger contractions. This positive feedback loop continues until the baby is born.

​​​​​​. Below is the image show you of the example

Nerve impulses from cervix transmitted to brain Brain stimulates pituitary gland to secrete oxytocin Head of baby pushes against cervix Oxytocin carried in bloodstream to uterus Oxytocin stimulates uterine contractions and pushes baby towards cervix