Objectives (5 - 7 minutes)

1. Understanding the muscular system in the human body: Students should be able to describe the main structures that make up the human muscular system, including muscles, tendons, and ligaments.

2. Understanding the function of the muscular system: Students should be able to explain how the muscular system contributes to body movement, maintaining posture, and producing heat.

3. Identifying and classifying muscles: Students should be able to identify and classify the major muscles of the human body, both by their location and by their function.

   • Secondary objective: stimulate students' curiosity and interest in studying the human body and its complexity.

During this stage, the teacher should present the objectives of the lesson clearly and concisely. It is important that students understand what is expected of them at the end of the lesson and what skills and knowledge they should acquire.

Introduction (10 - 15 minutes)

1. Review of previous concepts: The teacher should begin the lesson by quickly reviewing the concepts of human anatomy and physiology that were covered in previous lessons and that are essential for understanding the muscular system. This includes a brief recap of the concept of cell, tissue, organ, and system, as well as a review of the basic structure of the human body.

2. Problem-solving situations: The teacher should then present two problem-solving situations that encourage students to think about the importance of the muscular system. For example, "How do you think a person's life would be without the muscular system?" or "Why can some people lift heavy objects easily, while others have difficulty?"

3. Contextualization: Next, the teacher should contextualize the importance of studying the muscular system, explaining how it is involved in daily activities such as walking, running, eating, and even smiling. One could also mention how the muscular system is affected by diseases such as muscular dystrophy and amyotrophic lateral sclerosis (ALS).

4. Gaining students' attention: To capture students' attention, the teacher can share some curiosities about the muscular system. For example, "Did you know that the largest muscle in the human body is the gluteus maximus, located in the buttocks?" or "Did you know that babies have over 300 bones, but over time some of them fuse, and an adult has about 206 bones?"

By the end of this stage, students should be ready to begin exploring the muscular system in more depth, having understood the importance and relevance of this study.

Development (20 - 25 minutes)

1. Theory about the muscular system (10 - 12 minutes)

   • Definition and function: The teacher should begin the Development stage of the lesson by explaining what the muscular system is and what its function is in the human body. It should be emphasized that the muscular system is responsible for body movement, maintaining posture, and producing heat.
   • Structure: Next, the teacher should describe the basic structure of the muscular system, including the muscles, tendons, and ligaments. It should also be explained how muscles are made up of bundles of muscle fibers that contract and relax to allow body movement.
   • Types of muscles: The teacher should then explain that there are three types of muscles in the human body: skeletal striated muscles, which are voluntary and responsible for most of the body's movements; cardiac striated muscles, which are involuntary and form the heart muscle; and smooth muscles, which are also involuntary and are present in organs such as the stomach and intestines.
   • Classification of muscles: The teacher should explain that muscles can be classified in different ways, including by their location (for example, arm muscles, leg muscles, etc.) and by their function (for example, muscles that flex, extend, rotate, etc.).

2. Practical activity: Identification of muscles in the human body (5 - 7 minutes)

   • The teacher should then propose a practical activity where the students, in groups, must identify and mark the main muscles of the human body on a diagram. The teacher can provide students with a diagram of the human body with the main muscles, or ask the students to research and find one on their own. During the activity, the teacher should circulate around the room, providing guidance and answering questions.

3. Theory about muscular contraction (5 - 6 minutes)

   • Definition and processes involved: The teacher should explain what muscular contraction is and what processes are involved in this mechanism. The role of calcium, ATP, and the actin and myosin filaments should be addressed.
   • Types of contraction: The teacher should explain that there are three types of muscular contraction: isotonic contraction, where the muscle shortens and there is movement; isometric contraction, where the muscle does not shorten, but there is tension; and auxotonic contraction, which is a combination of the first two.

By the end of this stage, students should have acquired a good understanding of the human muscular system, including its structure, function, classification, and the nature of muscular contraction. They should also have had the opportunity to apply this knowledge in a practical way, identifying and marking the main muscles of the human body.

Feedback (8 - 10 minutes)

1. Review of concepts learned: The teacher should begin this stage by reviewing the main concepts covered in the lesson. This includes the definition of the muscular system, its structure, function, and classification, as well as the process of muscular contraction. The teacher can do this interactively, asking students to share what they remember about each concept.

2. Connection to the real world: The teacher should then facilitate a discussion on how what was learned in class connects to the real world. This can be done through questions such as "How can knowledge about the muscular system help us understand and deal with health problems such as muscular dystrophy or ALS?" or "How can understanding the muscular system help us improve performance in physical activities or sports?" The goal is to make students realize the relevance and applicability of what they have learned.

3. Reflection on learning: The teacher should then propose that students reflect on what they have learned during the lesson. To do this, one can ask questions such as "What was the most important concept you learned today?" or "What questions still need to be answered?" The teacher should encourage students to express their opinions and doubts, creating an open and welcoming learning environment.

4. Feedback to the teacher: Finally, the teacher should ask for feedback from the students about the lesson. This may include questions such as "What did you think of today's lesson?" or "What could be improved for future lessons?" Student feedback is a valuable tool for the teacher to assess the effectiveness of their lesson and make adjustments if necessary.

By the end of this stage, students should have consolidated their understanding of the human muscular system and its importance. They should also have had the opportunity to reflect on what they have learned and express their opinions and doubts.

Conclusion (5 - 7 minutes)

1. Summary of contents: The teacher should begin the Conclusion stage by recapitulating the main points covered during the lesson. This includes the definition of the muscular system, its structure, function, and classification, as well as the process of muscular contraction. It is important that the teacher do this recapitulation in a clear and concise manner, to reinforce student learning.

2. Connection between theory and practice: The teacher should then highlight how the lesson managed to connect theory, practice, and application of concepts. The teacher may mention, for example, how the practical activity of identifying muscles allowed students to apply theoretical knowledge in a concrete and meaningful way. In addition, the teacher can reinforce how understanding the muscular system has practical applications in everyday life, such as in performing physical activities and understanding muscular diseases.

3. Extra materials: The teacher should suggest additional materials for students to deepen their understanding of the muscular system. This may include books, videos, interactive anatomy websites, and learning apps. The teacher should briefly explain what each resource offers and how it can be useful for students' studies.

4. Importance of the subject: Finally, the teacher should emphasize the importance of studying the muscular system for understanding the functioning of the human body as a whole. The teacher may mention, for example, how the muscular system is involved in almost all the activities we perform, from the simplest, such as walking, to the most complex, such as playing a musical instrument. In addition, the teacher may reinforce how knowledge about the muscular system is fundamental for understanding and treating many diseases and injuries.

By the end of this stage, students should have consolidated their understanding of the muscular system and its importance. They should also have received guidance on how to continue learning about the subject, if they so wish.