Contextualization

The human body is a fascinating biological machine composed of several systems that work together to sustain life. Among these systems, the respiratory system stands out as one of the most vital. It is responsible for providing oxygen to every cell in our body and eliminating carbon dioxide, a waste product of cellular metabolism. Understanding the structure and functioning of this system is not only curious but also essential to comprehend how we keep our vital functions active.

The respiratory system is mainly composed of the lungs, airways, and respiratory muscles. The airways include organs such as the nose, pharynx, larynx, trachea, and bronchioles, which function as a channel for air to enter and exit the lungs. The lungs are the main organs of respiration, where oxygen from the air is exchanged for carbon dioxide in the blood. This exchange occurs in the alveoli, small air sacs surrounded by blood capillaries.

In addition to supporting respiration, the respiratory system also plays an important role in regulating blood pH and protecting against pathogens and foreign particles. Therefore, understanding its functioning is not just a matter of biology; it is about understanding a fundamental pillar for maintaining our health and well-being.

The relevance of the respiratory system becomes even more evident when we consider diseases and conditions that affect its function, such as asthma, bronchitis, and pneumonia, as well as the recent global scenario faced with the COVID-19 pandemic. The current relevance of this subject shows how crucial it is to have an in-depth knowledge of how our bodies process the air we breathe. This knowledge can save lives, informing care, prevention, and treatment of respiratory diseases.

The practical application of knowledge about the respiratory system goes beyond health care. Athletes, for example, use breathing techniques to improve performance and physical endurance. Singers and actors undergo specific training to control their breathing and voice. In polluting industries, understanding the respiratory system is essential for developing personal protective equipment against the inhalation of harmful substances.

To support the study of this fascinating and complex subject, students can consult reliable resources such as:

• The portal of the Oswaldo Cruz Foundation (Fiocruz), which offers quality scientific information on health, including the functioning of the respiratory system.
• The website of the Brazilian Society of Pulmonology and Tisiology (SBPT), which provides articles and educational resources on respiratory diseases.
• Educational videos on the YouTube channel "Manual do Mundo", which illustrate experiments and explain science concepts in a fun and accessible way.
• Textbooks recommended by the MEC and available in school libraries, which offer a detailed theoretical overview of the human body and its systems.

These resources will serve as a basis for classroom discussion and for building a solid understanding of the respiratory system and its vital function in our organism.

Practical Activity

Activity Title: "Building the Respiratory System"

Project Objective

The objective of this project is to allow students to build a model of the respiratory system, understanding its functioning, and identifying its main components. Through this practical activity, it is expected that students develop essential technical and socioemotional skills for learning.

Project Description

Groups of 3 to 5 students will work together to create a model of the respiratory system using recyclable and easily accessible materials. They should replicate the main structures, such as the airways and lungs, and demonstrate how gas exchange occurs. The proposed activity should be carried out within a one-week period, and each student should devote two to four hours to completing the project.

Materials Required

• Transparent PET bottles (2 for each group)
• Party balloons (5 for each group)
• Plastic or paper straws (10 for each group)
• Cardboard tubes (such as paper towel rolls)
• Adhesive tape or electrical tape
• Scissors (one per group)
• Clay or modeling dough
• Colored markers
• Paper, cardboard, or cardstock for labels

Detailed Step-by-Step

1. Preparation and Planning (30 minutes)

   • Each group should meet and discuss the structure of the respiratory system, based on information collected from the indicated resources.
   • Draw a simple sketch of the model they will build, identifying the function of each component.

2. Building the Airways (1 hour)

   • Use straws to represent the trachea and bronchioles.
   • Cut and join straws with adhesive tape to form a branched network simulating the airways within the lungs.

3. Modeling the Lungs (1 hour)

   • Insert the end of a balloon into each PET bottle (the mouth of the balloon should be facing out), simulating the lungs.
   • Secure the mouth of the balloon to the bottle opening with adhesive tape to make it airtight.

4. Building the Diaphragm (30 minutes)

   • Place a balloon cut at the base of each PET bottle, representing the diaphragm.

5. Final Assembly (1 hour)

   • Connect the straws (airways) to the inlet of the PET bottles (lungs).
   • Use the clay or modeling dough to seal and fix the connections.
   • Create labels for each part of the respiratory system and attach them to the respective components.

6. Demonstration and Testing (30 minutes)

   • Test the model by pulling and pushing the balloon at the base of the bottle to simulate breathing.
   • Observe the filling and emptying of the "lungs" (balloons inside the bottle) and explain how the movement of the "diaphragm" affects this process.

Project Deliverables

Students should deliver the following at the end of the project:

1. Physical Model of the Respiratory System

   • Three-dimensional representation, indicating the airways and lungs, built with the listed materials.

2. Written Report

   • Introduction: Description of the topic, relevance, and real-world application, along with the purpose of building the model.
   • Development: Detailed explanation of the model building process, the theory behind the anatomy of the respiratory system, and the discussion of the model's functionality.
   • Conclusion: Feedback on the main points learned, difficulties encountered, and how the model represents human respiration.
   • Bibliography: Listing of the research sources used, including books, websites, articles, and videos.

Connection Between Activities and Deliverables

The construction of the model will allow students to visualize and physically manipulate the structures that make up the respiratory system. By writing the report, they will have to reflect on the construction process and the interactions between the parts of the system. The report will function as a tool for reflection and knowledge consolidation.

In addition, by working in groups, students will develop time management, communication, and problem-solving skills. The need to divide tasks, discuss strategies, and make adjustments to the project involves a constant exercise in creative thinking and collaboration.