Feedback Mechanisms 2
by CHED on June 15, 2017
lesson duration of 15 minutes
under General Biology 2
generated on June 15, 2017 at 03:23 am
Tags: Feedback Mechanisms
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Generated: Jun 15,2017 11:23 AM
Feedback Mechanisms 2
( 1 hour and 15 mins )
Written By: CHED on July 19, 2016
Subjects: General Biology 2
Tags: Feedback Mechanisms
Resources
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Content Standard
The learners demonstrate an understanding of:
1. Plant and Animal Organ Systems and their Functions
2. Feedback Mechanisms
Performance Standard
The learners shall be able to:
develop a presentation (e.g. role-playing, dramatization and other forms of multimedia) to show how an organism
maintains homeostasis through the interaction of the various organ systems in the body
Learning Competencies
Describe examples of homeostasis (e.g., temperature regulation, osmotic balance and glucose levels) and the major
features of feedback loops that produce such homeostasis
Introduction 5 mins
Communicating Learning Objectives
1. Introduce the following learning objectives using any of the suggested protocols (Verbatim, Own words, Readaloud)
I. I can explain why there is a need for homeostasis
II. I can explain how feedback mechanisms maintain homeostasis
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III. I can differentiate a positive from a negative feedback
IV. I can outline some ways by which our body maintains homeostasis
Teacher Tip: The human body is composed of various organs with specific functions. Organs assemble to
form organ-systems that contribute to homeostasis inside the organism. Homeostasis is the condition
wherein steady state is regulated inside the organism in order for it to adapt to internal and external changes.
This is important for survival. Once homeostasis is disrupted, the organism may experience a disorder that
might affect its normal functions.
Motivation 10 mins
Homeostasis: A Balancing Act
1. Ask all learners to stand up and balance themselves on one foot.!After one minute, tell them to put their other foot
down. Let them share with each other what they experienced.!Tell them to take their resting pulse for 15 seconds.
Multiply this by 4 to have their pulse rate in 1 minute.!
2. Tell them to jog in place for 1 minute then take their pulse again for 15 seconds. Multiply this by 4 to have their pulse
rate in 1 minute. Let them share with each other what they experienced.
Teacher Tip: After the activities, ask 3 volunteers to share their experiences.
Tell the learners that they just experienced homeostasis.
In the second activity, respiration rate will increase during exercise due to the increase in carbon dioxide. The
heart rate will increase in order to remove the extra carbon dioxide and increase the amount of oxygen. When
things are normalized, the heart rate will go back to the resting state. How long does it take for this to
happen?
Instruction 40 mins
1. Ask the following questions: What is homeostasis? In the previous activities, how did the body maintain
homeostasis? What factors can disrupt homeostasis in the body?
2. Introduce the concept of feedback mechanism. What does the word feedback mean? With what do you associate
this term? Can you give an example of a feedback? Why is a feedback important in the body?
3. Show the following video about homeostasis.
I. Positive and Negative Feedback Loops: Post this video (https://www.youtube.com/watch?
v=CLv3SkF_Eag&spfreload=10) (Retrieved 11/15) or show diagrams and pictures and explain what homeostatic
mechanisms took place. Then ask, “How was the system maintained?”
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Homeostasis is the physiological consistency of the body despite external fluctuations. All complex multicellular
organisms maintain a stable internal environment using their organ systems.
Homeostasis in a general sense refers to stability, balance or equilibrium. It is the body's attempt to maintain a
constant internal environment. Maintaining a stable internal environment requires constant monitoring and adjustments
as conditions change. The adjustment of physiological systems within the body is called homeostatic regulation.
The homeostatic control has three components:
II. A receptor (sense organ) to detect a change
III. A center of control (the brain or the spinal cord) that will process and integrate what is happening I
V. An effector (muscle cells or organs/ glands) to produce a response appropriate to the change.
There are ways of communication among these components (basically through the nervous and endocrine control).
When a change of variable occurs, there are two main types of feedback to which the system reacts:
1. Negative feedback: a reaction in which the system responds in such a way as to reverse the direction of change.
I. Thermoregulation
II. Carbon dioxide concentration
III. Blood sugar level
2. Positive feedback: a response is occurs to amplify the change in the variable. (This has a destabilizing effect, so
does not result in homeostasis. Positive feedback is less common in naturally occurring systems than negative
feedback, but it has its applications.)
I. For example, in nerves, a threshold electric potential triggers the generation of a much larger action potential.
II. Blood clotting
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III. Events in childbirth
Evaluation 10 mins
1. Give examples of feedback mechanisms in the body.
Enrichment 10 mins
1. Describe the homeostatic control of the following:
I. blood glucose level
II. temperature regulation
III. water and salt balance
IV. carbon dioxide concentration
Assignment:
1. Research on the following disorders. Discuss how homeostasis is disrupted. Form a group with 5 members
I. Diabetes mellitus
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II. Hemophilia
III. Hemorhagic fever
IV. Hypothermia
V. Diarrhea
2. Prepare a 5 – 10 slide presentation about your topic. You will be evaluated by your classmates using the rubrics.
3. Each will be given a maximum of 10 minutes to present.
Download Teaching Guide Book 0 mins
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