homeostasis case study answers

The Biology Corner

Biology Teaching Resources

Tag: homeostasis

Characteristics of Life

Students read descriptions of animals and match to one of the characteristics of life: energy, cells, DNA, growth, response, and homeostasis.

How do Mammals Maintain Their Temperature (CER)

Students examine graphs and images to develop an understanding of how mammals maintain their body temperatures compared to ectothermic animals.

Case Study – Tibetans and Altitude (Remote)

This case study is a remote alternative to “How Do Tibetans Survive High Altitudes.” The remove version is shorter and does not require as much guidance by the instructor. I created this version with Google slides, so students can type their answers directly onto the slide. I made remote versions of several activities because I…

Investigation: How Does Exercise Affect Heart Rate

Design and conduct an experiment to measure the effect of exercise on heart rate. Aligned to NGSS standard on feedback mechanisms.

Feedback Loops: Insulin and Glucagon

The Next Generation Science Standards includes feedback loops and homeostasis as a standard for life science.  While homeostasis is a theme for many units in biology, feedback mechanisms are fairly specific.  In fact, this is probably the most oddly specific topic found in NGSS.   If you are trying to include it, most younger students…

Investigation: How Does Temperature Affect Respiration Rates

This lab is focused on fish and the metabolism of ectothermic (warm-blooded) animals.  The investigation  also be useful for beginning students in reinforcing good lab procedures and graphing.  I’m always surprised by how many students have difficulty reading thermometers and setting up a water bath. This lab has been redesigned to make it simple and quick.…

• school Campus Bookshelves
• menu_book Bookshelves
• perm_media Learning Objects
• login Login
• how_to_reg Request Instructor Account
• hub Instructor Commons
• Download Page (PDF)
• Download Full Book (PDF)
• Periodic Table
• Physics Constants
• Scientific Calculator
• Reference & Cite
• Tools expand_more
• Readability

selected template will load here

This action is not available.

10.7: Homeostasis and Feedback

• Last updated
• Save as PDF
• Page ID 17075

• Suzanne Wakim & Mandeep Grewal
• Butte College

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

\( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

\( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)

( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)

\( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

\( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)

\( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

\( \newcommand{\Span}{\mathrm{span}}\)

\( \newcommand{\id}{\mathrm{id}}\)

\( \newcommand{\kernel}{\mathrm{null}\,}\)

\( \newcommand{\range}{\mathrm{range}\,}\)

\( \newcommand{\RealPart}{\mathrm{Re}}\)

\( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

\( \newcommand{\Argument}{\mathrm{Arg}}\)

\( \newcommand{\norm}[1]{\| #1 \|}\)

\( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)

\( \newcommand{\vectorA}[1]{\vec{#1}}      % arrow\)

\( \newcommand{\vectorAt}[1]{\vec{\text{#1}}}      % arrow\)

\( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

\( \newcommand{\vectorC}[1]{\textbf{#1}} \)

\( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)

\( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)

\( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)

Steady as She Goes

This device looks simple, but it controls a complex system that keeps a home at a steady temperature. The device is an old-fashioned thermostat. The dial shows the current temperature in the room and also allows the occupant to set the thermostat to the desired temperature. A thermostat is a commonly cited model of how living systems, including the human body, maintain a steady state called homeostasis.

What is Homeostasis?

Homeostasis is the condition in which a system such as the human body is maintained in a more-or-less steady state. It is the job of cells, tissues, organs, and organ systems throughout the body to maintain many different variables within narrow ranges that are compatible with life. Keeping a stable internal environment requires continuous monitoring of the internal environment and constantly making adjustments to keep things in balance.

Setpoint and Normal Range

For any given variable, such as body temperature or blood glucose level, there is a particular setpoint that is the physiological optimum value. For example, the setpoint for human body temperature is about 37 ºC (98.6 ºF). As the body works to maintain homeostasis for temperature or any other internal variable, the value typically fluctuates around the set point. Such fluctuations are normal as long as they do not become too extreme. The spread of values within which such fluctuations are considered insignificant is called the normal range . In the case of body temperature, for example, the normal range for an adult is about 36.5 to 37.5 ºC (97.7 to 99.5 ºF).

Maintaining Homeostasis

Homeostasis is normally maintained in the human body by an extremely complex balancing act. Regardless of the variable being kept within its normal range, maintaining homeostasis requires at least four interacting components: stimulus, sensor, control center, and effector.

• The stimulus is provided by the variable that is being regulated. Generally, the stimulus indicates that the value of the variable has moved away from the set point or has left the normal range.
• The sensor monitors the values of the variable and sends data on it to the control center.
• The control center matches the data with normal values. If the value is not at the set point or is outside the normal range, the control center sends a signal to the effector.
• The effector is an organ, gland, muscle, or other structure that acts on the signal from the control center to move the variable back toward the set point.

Each of these components is illustrated in Figure \(\PageIndex{2}\). The diagram on the left is a general model showing how the components interact to maintain homeostasis. The stimulus activates the sensor. The sensor activates the control system that regulates the effector. The diagram on the right shows the example of body temperature. From the diagrams, you can see that maintaining homeostasis involves feedback, which is data that feeds back to control a response. High body temperature may stimulate the temperature regulatory center of the brain to activate the sweat glands to bring the body temperature down. When body temperature reaches normal range, it acts as negative feedback to stop the process. Feedback may be negative or positive. All the feedback mechanisms that maintain homeostasis use negative feedback. Biological examples of positive feedback are much less common.

Negative Feedback

In a negative feedback loop , feedback serves to reduce an excessive response and keep a variable within the normal range. Examples of processes controlled by negative feedback include body temperature regulation and control of blood glucose.

Body Temperature

Body temperature regulation involves negative feedback whether it lowers the temperature or raises it (Figure \(\PageIndex{3}\)).

Cooling Down

The human body’s temperature regulatory center is the hypothalamus in the brain. When the hypothalamus receives data from sensors in the skin and brain that body temperature is higher than the setpoint, it sets into motion the following responses:

• Blood vessels in the skin dilate (vasodilation) to allow more blood from the warm body core to flow close to the surface of the body, so heat can be radiated into the environment.
• As blood flow to the skin increases, sweat glands in the skin are activated to increase their output of sweat (diaphoresis). When the sweat evaporates from the skin surface into the surrounding air, it takes the heat with it.
• Breathing becomes deeper, and the person may breathe through the mouth instead of the nasal passages. This increases heat loss from the lungs.

When the brain’s temperature regulatory center receives data that body temperature is lower than the setpoint, it sets into motion the following responses:

• Blood vessels in the skin contract (vasoconstriction) to prevent blood from flowing close to the surface of the body. This reduces heat loss from the surface.
• As the temperature falls lower, random signals to skeletal muscles are triggered, causing them to contract. This causes shivering, which generates a small amount of heat.
• The thyroid gland may be stimulated by the brain (via the pituitary gland) to secrete more thyroid hormones. This hormone increases metabolic activity and heat production in cells throughout the body.
• The adrenal glands may also be stimulated to secrete the hormone adrenaline. This hormone causes the breakdown of glycogen (the carbohydrate used for energy storage in animals) to glucose, which can be used as an energy source. This catabolic chemical process is exothermic, or heat producing.

Blood Glucose

In the control of the blood glucose level, certain endocrine cells in the pancreas called alpha and beta cells, detect the level of glucose in the blood. Then they respond appropriately to keep the level of blood glucose within the normal range.

• If the blood glucose level rises above the normal range, pancreatic beta cells release the hormone insulin into the bloodstream. Insulin signals cells to take up the excess glucose from the blood until the level of blood glucose decreases to the normal range.
• If the blood glucose level falls below the normal range, pancreatic alpha cells release the hormone glucagon into the bloodstream. Glucagon signals cells to break down stored glycogen to glucose and release the glucose into the blood until the level of blood glucose increases to the normal range.

Positive Feedback

In a positive feedback loop , feedback serves to intensify a response until an endpoint is reached. Examples of processes controlled by positive feedback in the human body include blood clotting and childbirth.

Blood Clotting

When a wound causes bleeding, the body responds with a positive feedback loop to clot the blood and stop blood loss. Substances released by the injured blood vessel wall begin the process of blood clotting. Platelets in the blood start to cling to the injured site and release chemicals that attract additional platelets. As the platelets continue to amass, more of the chemicals are released and more platelets are attracted to the site of the clot. The positive feedback accelerates the process of clotting until the clot is large enough to stop the bleeding.

Figure \(\PageIndex{4}\) shows the positive feedback loop that controls childbirth. The process normally begins when the head of the infant pushes against the cervix. This stimulates nerve impulses, which travel from the cervix to the hypothalamus in the brain. In response, the hypothalamus sends the hormone oxytocin to the pituitary gland, which secretes it into the bloodstream so it can be carried to the uterus. Oxytocin stimulates uterine contractions, which push the baby harder against the cervix. In response, the cervix starts to dilate in preparation for the passage of the baby. This cycle of positive feedback continues, with increasing levels of oxytocin, stronger uterine contractions, and wider dilation of the cervix until the baby is pushed through the birth canal and out of the body. At that point, the cervix is no longer stimulated to send nerve impulses to the brain, and the entire process stops.

When Homeostasis Fails

Homeostatic mechanisms work continuously to maintain stable conditions in the human body. Sometimes, however, the mechanisms fail. When they do, homeostatic imbalance may result, in which cells may not get everything they need or toxic wastes may accumulate in the body. If homeostasis is not restored, the imbalance may lead to disease or even death. Diabetes is an example of a disease caused by homeostatic imbalance. In the case of diabetes, blood glucose levels are no longer regulated and may be dangerously high. Medical intervention can help restore homeostasis and possibly prevent permanent damage to the organism.

Feature: My Human Body

Diabetes is diagnosed in people who have abnormally high levels of blood glucose after fasting for at least 12 hours. A fasting level of blood glucose below 100 is normal. A level between 100 and 125 places you in the pre-diabetes category, and a level higher than 125 results in a diagnosis of diabetes.

Of the two types of diabetes, type 2 diabetes is the most common, accounting for about 90 percent of all cases of diabetes in the United States. Type 2 diabetes typically starts after the age of 40. However, because of the dramatic increase in recent decades in obesity in younger people, the age at which type 2 diabetes is diagnosed has fallen. Even children are now being diagnosed with type 2 diabetes. Today, about 30 million Americans have type 2 diabetes, and another 90 million have pre-diabetes.

You are likely to have your blood glucose level tested during a routine medical exam. If your blood glucose level indicates that you have diabetes, it may come as a shock to you because you may not have any symptoms of the disease. You are not alone, because as many as one in four diabetics does not know they have the disease. Once the diagnosis of diabetes sinks in, you may be devastated by the news. Diabetes can lead to heart attacks, strokes, blindness, kidney failure, and loss of toes or feet. The risk of death in adults with diabetes is 50 percent greater than it is in adults without diabetes, and diabetes is the seventh leading cause of death in adults. In addition, controlling diabetes usually requires frequent blood glucose testing, watching what and when you eat and taking medications or even insulin injections. All of this may seem overwhelming.

The good news is that changing your lifestyle may stop the progression of type 2 diabetes or even reverse it. Here’s how:

• Lose weight. Any weight loss is beneficial. Losing as little as seven percent of your weight may be all that is needed to stop diabetes in its tracks. It is especially important to eliminate excess weight around your waist.
• Exercise regularly. You should try to exercise five days a week for at least 30 minutes. This will not only lower your blood sugar and help your insulin work better; it will also lower your blood pressure and improve your heart health. Another bonus of exercise is that it will help you lose weight by increasing your basal metabolic rate.
• Adopt a healthy diet. Decrease your consumption of refined carbohydrates such as sweets and sugary drinks. Increase your intake of fiber-rich foods such as fruits, vegetables, and whole grains. About a quarter of each meal should consist of high-protein foods, such as fish, chicken, dairy products, legumes, or nuts.
• Control stress. Stress can increase your blood glucose and also raise your blood pressure and risk of heart disease. When you feel stressed out, do breathing exercises or take a brisk walk or jog. Also, try to replace stressful thoughts with more calming ones.
• Establish a support system. Enlist the help and support of loved ones as well as medical professionals such as a nutritionist and diabetes educator. Having a support system will help ensure that you are on the path to wellness and that you can stick to your plan.
• What is homeostasis?
• Define the setpoint and normal range for physiological measures.
• Identify and define the four interacting components that maintain homeostasis in feedback loops.
• Compare and contrast negative and positive feedback loops.
• Explain how negative feedback controls body temperature.
• Give two examples of physiological processes that are controlled by positive feedback loops.
• brings a variable’s level back to a normal range
• can lower, but not raise, body temperature
• is the type of feedback involved in blood clotting
• Is this an example of negative or positive feedback? Explain your answer.
• What do you think might be the evolutionary benefit of the milk production regulation mechanism described in part a?
• Explain why homeostasis is regulated by negative feedback loops, rather than positive feedback loops.
• the top of a normal range
• the bottom of a normal range
• in the middle of a normal range
• the point at which changes can no longer occur
• What is the stimulus in this system? Explain your answer.
• What is the control center in this system? Explain your answer.
• What is the pituitary considered in this system: stimulus, sensor, control center, or effector? Explain your answer.

Explore More

Attributions.

• Honeywell thermostat by Vincent de Groot , licensed CC BY 4.0 via Wikimedia Commons
• Negative feedback loop by OpenStax , licensed CC BY 4.0 via Wikimedia Commons
• Temperature Regulation dedicated CC0 via Wikimedia Commons
• Pregnancy-Positive Feedback by OpenStax, licensed CC BY 4.0 via Wikimedia Commons
• Text adapted from Human Biology by CK-12 licensed CC BY-NC 3.0

Homeostasis Lesson Ideas

Even though homeostasis is something they focus more on in anatomy, I decided I wanted to dive a little deeper into the topic with my biology students to make it “stick.” Instead of just discussing it as a characteristic of life and moving on, I added some fun activities to help them remember it better. It has definitely helped! 

Here is a round-up of resources you can use while teaching homeostasis: 1. AMOEBA SISTERS- This Youtube video may go into a little more depth than biology teachers need to cover, but it’s still a great video. They also have worksheets that accompany the videos on their website. 2. PBS INTERACTIVE- Here is a quick interactive from PBS you can use with students. In this “body control center” activity students need to monitor the person’s pulse, oxygen, blood pressure, body temperature, and glucose level. Students will learn that our body systems and responses are all connected. 

​ 8. STATION LAB- Looking to have your students get up and moving around the room? In this engaging station activity , students will rotate through 10 stations and complete a quick activity relating to homeostasis at each station. 

​Rock on,

• Read more about: Body Systems , Cells

Hi, I'm Becca!

Search the site, browse by category.

• A list of ALL blog posts
• Back to School
• Biochemistry
• Body Systems
• Classification
• Classroom Decor
• Classroom Management
• Distance Learning
• End of the School Year
• Experiments
• Field Trips
• For NEW Teachers
• Formative Assessment
• Media in the Classroom
• Microscopes
• Photosynthesis & Respiration
• Plate Tectonics
• Sustainability
• Teacher Tips
• Weather and Climate

Get Freebies!

You might also like....

Science Seek and Finds

Layers of the Earth Lessons

Teaching the Electromagnetic Spectrum

Let me help your students with experimental design!

Privacy Overview

Universities

• All Universities
• California State University
• Virtual High School
• CFA Institute
• Indiana University South Bend
• University of California San Diego
• The University of North Carolina at Charlotte
• John Jay College of Criminal Justice
• All Courses
• 0620 IGCSE | Chemistry
• MKT 498A | Marketing Internship
• POLS 372 | Principles and Methods of Political Science
• 0625 IGCSE | Physics
• CSE 114 | Introduction to Object-Oriented Programming
• SOC/ANT 110 | Drug Use and Abuse
• BUS-A 201 | Introduction to Financial Accounting
• 0470 IGCSE | History
• Correctional Evolution: Principles to Modern Practices
• Persuasive Outline
• L'Hopital's Rule
• Power Rule for Derivatives

https://keepnotes.com/virtual-high-school/stem/1634-gizmo-answer-key-human-homeostasis

Tell us what’s wrong with it:

Thanks, got it! We will moderate it soon!

Human Homeostasis Gizmo Answer Key

Academic year

Description

Name: Jimmy Gillespie Date: 09-01-2022 Student Exploration: Human Homeostasis Directions: Follow the instructions to go through the simulation. Respond to the questions andprompts in the orange boxes. Vocabulary: dehydration, heat stroke, homeostasis, hypothermia, involuntary, thermoregulation, voluntary Prior Knowledge Questions (Do these BEFORE using the Gizmo.) A thermostat is a device that regulates the temperature inside a building.1. What does a thermostat do if it gets too cool? turns on the heater 2. What does a thermostat do if it gets too hot? the air conditioning system is turned on 3. How do our bodies sometimes act like a thermostat? our body modifies to control the temperature inside us like a thermostat Gizmo Warm-up To survive, an organism must be able to maintain stable internalconditions in a changing environment. This process is called homeostasis . The Human Homeostasis Gizmo allows you to explore how the human body stays at a nearly constant temperature indifferent conditions. Notice the Air temp. and Body temp. thermometers representing the air temperature and body temperature. What is the initial air temperature? zero degrees celsius 1. What is the initial body temperature? thirty seven degrees celsius 2. Next to each factor listed below, write “increase,” “decrease,” or “same” based on how you expect that factor to affect body temperature. Raising air temperature: increase Sweating: decrease Lowering air temperature: decrease Shivering: increase Adding clothing: increase Exercising: increase Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

Activity A: Body temperature Get the Gizmo ready: ● If necessary, click Reset ( ). Question: What factors increase or decrease body temperature? 1. Observe: With the Air temp. at 0 °C (32 °F) and Body temp. at 37 °C (99 °F), click Play ( ). After one simulated hour (does not have to be exact), click Pause ( ). What is the body temperature after one hour? thirty seven degrees celsius 2. Gather data: Fill in the first line of the data table below. Then, use the same procedure to test the effect of each of the following factors. Click Reset between each trial. Record the initial and final body temperatures in the table below. (Leave the last column blank.) ● Set the Exercise level to 70%. (All other settings in default position.) ● Click Reset . Set the Sweat level to 70%. (All other settings in default position.) ● Click Reset . Below Body position , click Shivering . (Other settings in default mode.) ● Click Reset . Next to Clothing , click Add four times to add a sweatshirt, hat, pants, and parka. (Other settings in default mode.) Factor Initial body temp. Body temp. after one hour Effect of factor on body temperature Standing still 37 36 decrease Exercising 37 39 increase Sweating 37 35 decrease Shivering 37 37 stayed the same Adding clothing 37 36 decrease 3. Analyze: To determine the effect of a factor on body temperature, compare the final body temperature with that factor to the final body temperature while standing still. Based on this comparison, fill in the last columnof the data table. A. Which factor raised body temperature the most? Exercising B. Why do you think this process raises body temperature? Using more energy moreheat is produced, raisingbody temperature C. Which factor lowered body temperature the most? Sweating Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

D. Why do you think this process lowers body temperature? Sweat fluid cools the body,lowering body temperature. Activity B: Thermoregulation Get the Gizmo ready: ● Click Reset . Introduction: Thermoregulation is the process in which a steady temperature is maintained inside the body. Some responses to temperature changes, such as sweating and shivering, are involuntary —they occur automatically. Other actions, such as exercising or putting on clothes, are called voluntary responses because they are things we have to think about doing. Question: In the Human Homeostasis Gizmo, you can control both involuntary and voluntary responses to temperature changes. How good are you at thermoregulation? 1. Play the Gizmo: Click Play . After one hour, the air temperature will start to fluctuate. Using what you have learned, try to maintain a steady body temperature by manipulating the Exercise level , Sweat level , Body position , and Clothing . (You may wish to click Pause occasionally to give yourself time to think.) Click Pause after at least 10 hours have passed, if you can survive that long! Select the GRAPH tab. ✏ Sketch the resulting graph into the space at right. Click the image to select EDIT to use the drawing tool. What does this graph show? Remained unchanged 2. Investigate: Click Reset . Click Play , and deliberately create a situation in which the body temperature gets so low that the simulation stops. A. How did you do this? Removed all clothing and turned sweating allthe way up. B. What is the name for this condition? Hypothermia C. At what body temperature is immediate medical treatment required? thirty degrees C 3. Investigate: Click Reset . Click Play , and create a situation in which the body temperature gets so high that the simulation stops. A. How did you do this? Put all the clothing on and exercise all the wayup B. What is the name for this condition? Heat stroke Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

C. At what body temperature is immediate medical treatment required? Forty one degrees C 4. Challenge yourself: Click Reset . Click Play , and see if you can maintain a constant body temperature of 37 °C (99 °F) for 24 simulated hours or more. You will have to click Drink water or Eat food to avoid dehydration (lack of water) and low blood sugar. If the Fatigue level gets too high, you will have to rest. If you succeed, click Pause . Select the GRAPH tab and click the camera ( ) icon to take a snapshot of the graph. Right-click the image, and click Copy Image. Paste the snapshot into the box below. 5. Analyze: Select the TABLE tab. The air temperature and body temperature are recorded every hour. Scroll through the table to find the highest and lowest air temperatures. A. What was the highest air temperature you had to deal with? Zero degrees C B. How did you respond to this temperature? Removed or added garments, worked out, andsweated C. What was the lowest air temperature in the simulation? Zero degrees C D. How did you maintain a constant body temperature at this time? I removed and added clothing as well as exercisedand sweat 6. Think and discuss: Other than the options available in the Human Homeostasis Gizmo, what other methods are used to maintain body temperature? Try to think of both voluntary and involuntary responses. Going inside, blankets, turning on a fan 7. Critique: On this page, describe the advantages and disadvantages of the model of human homeostasis used in the Gizmo. In what ways is the model realistic? What factors are not included in the model? The ability to experiment with various variables and discover how they affect a person'sbody temperature is an advantage of this gadget. The model has the drawback of lacking asleep factor. The model is less realistic as a result of this element. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

Please login or register to post comments

Related Documents

• Moment of Inertia Gizmo Answer Key

Recommended Documents

Lecture Note

New Documents from this Uni