Conceptualizing A System: Introduction to Anatomy and Physiology: Systems, Subsystems and Balance

Tricia Shelton
Type Category
Instructional Materials
Lesson/Lesson Plan
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



This unit challenges high school students to uncover answers for the cause of death of a teenage football player while building an understanding of the role of the urinary system in maintaining homeostasis. The unit first engages students by watching a news clip about the tragic death of a healthy, vibrant young man who died from drinking too much water and Gatorade during football practice. Students then consider the driving question, “If water is necessary for survival, how can such an essential substance kill us?” The unit utilizes a storyline of this phenomenon with four additional phenomena-driven questions that are central to the unit. The phenomena-driven questions are 1) What are the normal components of urine? 2) How is urine made? 3) How is the urinary system controlled/regulated? 4) How does the urinary system interact with other systems to keep an organism alive?  The lessons in this unit are structured around the 5E instructional model (Engage, Explore, Explain, Elaborate, and Evaluate), and the lessons outline a number of techniques to deepen student understanding of the concepts in this unit. The focus throughout the unit is not on what students know but how they know what they learn about homeostasis and the urinary system. Students write and share explanations, use teacher models and generate their own models, make claims using evidence they generated from lab activities, and create and show a video of what they have learned. Extensive background and supplemental teacher materials are provided.  Teachers are encouraged and supported in techniques for using specific feedback and reflective questioning, allowing multiple attempts at mastery and using criterion-based evidence for assessment. Anecdotal and formative assessments are also included.

Intended Audience

Educator and learner
Educational Level
  • High School
  • High School
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

HS-LS1-3 Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis.

Clarification Statement: Examples of investigations could include heart rate response to exercise, stomate response to moisture and temperature, and root development in response to water levels.

Assessment Boundary: Assessment does not include the cellular processes involved in the feedback mechanism.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
This Performance Expectation is explicitly addressed in several places in this unit. In Explore 2 students generate data to support claims with evidence for medical diagnosis using urinalysis; in Explore 3 students use a computer simulation entitled Animated Biology: Keeping An Athlete Running to make adjustments to maintain a runner’s internal environment; and in Elaborate 2 students plan and conduct an investigation to determine properties of semi-permeable membranes in relation to cells. Teachers should pay special attention to the additional provided questions and the portions of the rubrics that specifically address planning and carrying out investigations.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
Student activities throughout this unit work together to address this Practice. In the Engage section students develop a model with drawings and writing to show their initial thinking of what happened to the victim’s body cells. Within other parts of this unit’s lessons students use and design models and share their experience and evidence with the models to answer three of the phenomena-driven questions. For example, in Explore 2 students explain the normal components and functions of the urinary system by analyzing models and in Explain 2, students discuss ideas, plan a video, create and show the video to classmates to communicate their understanding of their chosen model as it relates to homeostasis and the urinary system. Student engagement and understanding could be enhanced by having students work in small groups, while holding periodic small group discussions and utilizing the questions provided.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
The driving question on the death of the teenager explicitly relates to this Disciplinary Core Idea. In this unit students are trying to determine what external conditions could cause the malfunctioning of the teenager’s urinary system in terms of feedback mechanisms and how that negatively impacted his urinary system as well as other body systems, namely circulation and respiration to cause death. To gain a deep understanding of the Disciplinary Core Idea and to make connections to the Crosscutting Concepts, students make claims backed with evidence throughout this unit. Students could work collaboratively to defend their explanations based upon evidence and share their explanations between groups of students.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
To gain understanding of the structure and function of the urinary system, students work with or develop models throughout this unit. For example, models are emphasized in Explore 2 as students work with four different models. The models include a dialysis tubing and synthetic blood model, a bean and colander model, a nephron structure and function model and a sheep kidney are all used. A thorough list of questions for the teacher to use to emphasize the relationship of structure and function to the models is provided with each of the four models. An example of such questions is, “What is inaccurate or misleading about this model?” A rubric for using models and developing models as well as questions relating to the effectiveness of models are provided. In order to have the students using and developing models not overshadow the relationship of structure and function the teacher might ask students to relate other examples of structure and function of systems that are familiar with.

Resource Quality

  • Alignment to the Dimensions of the NGSS: The unit focuses on the phenomena of the death of a high school football player by water intoxication and is built around the driving question, “If water is necessary for survival, how can such an essential substance kill us?” The author identifies the Performance Expectations, The Disciplinary Core Idea and the Crosscutting Concept explicitly addressed in this unit. Each of the three dimensions is enumerated within the section of the unit that most explicitly addresses that dimension along with a summative or purpose statement of the 5E instructional Model. For instance, Explain1: LS1-2 Models, Constructing Explanations, Systems and Systems Models. Bulleted statements in the teacher notes provide suggestions and questions to ask students for teachers to emphasize three dimensional learning.

  • Instructional Supports: Students want to uncover answers of why this teenager died and this provides a natural hook to generate student enthusiasm. The unit is written so that students have an opportunity to share their thinking within their “mini think tank” triads as well as in a video. Students developing, producing and sharing a video is also a positive hook to engage student interest in this unit. Teachers are encouraged to serve as a facilitator or coach. To assist teachers in this role, substantive questions are included for each of the instructional 5Es for the teacher to ask while circulating between groups to help students clarify their thinking. Students are encouraged to ask questions throughout the unit and post their questions to the classroom Google Wall. A list of examples from students is included. Students make drawings with “microscope eyes” and constantly share, revise, add to, and redraw their models and claims throughout the unit. Teachers are encouraged to allow students to make changes until mastery is achieved. A list of common misconceptions relating to this unit is included and teachers are encouraged to be listening for any misconceptions and to help students clarify their thinking. Online critical readings are identified and student reflection questions relating to the readings are provided. The author notes that the teacher should make sure that all students have an opportunity to construct questions and that teachers encourage all students to participate in their triad. This is a positive way for differentiation of the included lesson activities. The author suggests that struggling students are spread throughout the triads in an effort to encourage their participation. Because there are so many different facets to this unit, a flow chart or brief outline of the 5Es and goals of each activity would be helpful to teachers implementing this unit.

  • Monitoring Student Progress: Ongoing assessment questions are provided as part of the teacher resources for each of the 5Es. The Evaluate section includes formative assessment questions requiring student’ written explanations of their understanding. A formal assessment coaching rubric and a HS Constructing Explanations Rubric is also provided. Anecdotal assessment ideas are given throughout the unit as well as rubrics for modeling. The embedded assessments address three dimensional learning by emphasizing models, structure and function and planning and carrying out investigations.

  • Quality of Technological Interactivity: Technology is used in a computer simulation that is interactive in Explore 3 and is also utilized by students for research but the unit is not technology-based.