As an introduction to bioengineering, student teams are given the engineering challenge to design and build prototype artificial limbs using a simple syringe system and limited resources. As part of a NASA lunar mission scenario, they determine which substance, water (liquid) or air (gas), makes the appendages more efficient.

Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Describe epithelial tissues
Discuss the different types of connective tissues in animals
Describe three types of muscle tissues
Describe nervous tissue

By the end of this section, you will be able to do the following:

Classify the different types of bones in the skeleton
Explain the role of the different cell types in bone
Explain how bone forms during development

Students use a tension-compression machine (or an alternative bone-breaking setup) to see how different bones fracture differently and with different amounts of force, depending on their body locations. Teams determine bone mass and volume, calculate bone density, and predict fracture force. Then they each test a small animal bone (chicken, turkey, cat) to failure, examining the break to analyze the fracture type. Groups conduct research about biomedical challenges, materials and repair methods, and design repair treatment plans specific to their bones and fracture types, presenting their design recommendations to the class.

Students are introduced to the challenge question, which revolves around proving that a cabinet x-ray system can produce bone mineral density images. Students work independently to generate ideas from the questions provided, then share with partners and then with the class as part of the Multiple Perspectives phase of this unit. Then, as part of the associated activity, students explore multiple websites to gather information about bone mineral density and answer worksheet questions, followed by a quiz on the material covered in the articles.

Students learn about the role engineers and engineering play in repairing severe bone fractures. They acquire knowledge about the design and development of implant rods, pins, plates, screws and bone grafts. They learn about materials science, biocompatibility and minimally-invasive surgery.

Students examine an image produced by a cabinet x-ray system to determine if it is a quality bone mineral density image. They write in their journals about what they need to know to be able to make this judgment. Students learn about what bone mineral density is, how a BMD image can be obtained, and how it is related to the x-ray field. Students examine the process used to obtain a BMD image and how this process is related to mathematics, primarily through logarithmic functions. They study the relationship between logarithms and exponents, the properties of logarithms, common and natural logarithms, solving exponential equations and Beer's law.

A two-part tutorial illustrating the structure and growth of bones, followed by a description of the cartilage model. [8:27]

Students investigate the bone structure of a turkey femur and then create their own prototype versions as if they are biomedical engineers designing bone transplants for a bird. The challenge is to mimic the size, shape, structure, mass and density of the real bone. Students begin by watching a TED Talk about printing a human kidney and reading a news article about 3D printing a replacement bone for an eagle. Then teams gather data—using calipers to get the exact turkey femur measurements—and determine the bone’s mass and density. They make to-scale sketches of the bone and then use modeling clay, plastic drinking straws and pipe cleaners to create 3D prototypes of the bone. Next, groups each cut and measure a turkey femur cross-section, which they draw in CAD software and then print on a 3D printer. Students reflect on the design/build process and the challenges encountered when making realistic bone replacements. A pre/post-quiz, worksheet and rubric are included. If no 3D printer, shorten the activity by just making the hand-generated replicate bones.

After learning, comparing and contrasting the steps of the engineering design process (EDP) and scientific method, students review the human skeletal system, including the major bones, bone types, bone functions and bone tissues, as well as other details about bone composition. Students then pair-read an article about bones and bone growth and compile their notes to summarize the article. Finally, students complete a homework assignment to review the major bones in the human body, preparing them for the associated activities in which they create and test prototype replacement bones with appropriate densities. Two PowerPoint(TM) presentations, pre-/post-test, handout and worksheet are provided.

After completing the associated lesson and its first associated activity, students are familiar with the 20 major bones in the human body knowing their locations and relative densities. When those bones break, lose their densities or are destroyed, we look to biomedical engineers to provide replacements. In this activity, student pairs are challenged to choose materials and create prototypes that could replace specific bones. They follow the steps of the engineering design process, researching, brainstorming, prototyping and testing to find bone replacement solutions. Specifically, they focus on identifying substances that when combined into a creative design might provide the same density (and thus strength and support) as their natural counterparts. After iterations to improve their designs, they present their bone alternative solutions to the rest of the class. They refer to the measured and calculated densities for fabricated human bones calculated in the previous activity, and conduct Internet research to learn the densities of given fabrication materials (or measure/calculate those densities if not found online).

Students extend their knowledge of the skeletal system to biomedical engineering design, specifically the concept of artificial limbs. Students relate the skeleton as a structural system, focusing on the leg as structural necessity. They learn about the design considerations involved in the creation of artificial limbs, including materials and sensors.

Students use wood, wax paper and oil to investigate the importance of lubrication between materials and to understand the concept of friction. Using wax paper and oil placed between pieces of wood, the function of lubricants between materials is illustrated. Students extend their understanding of friction to bones and joints in the skeletal system and become aware of what engineers can do to help reduce friction in the human body as well as in machines.

Students learn how forces affect the human skeletal system through fractures and why certain bones are more likely to break than others depending on their design and use in the body. They learn how engineers and doctors collaborate to design effective treatments with consideration for the location, fracture severity and patient age, as well as the use of biocompatible materials. Learning the lesson content prepares students for the associated activity in which they test small animal bones to failure and then design treatment repair plans.

Students operate mock 3D bioprinters in order to print tissue constructs of bone, muscle and skin for a fictitious trauma patient, Bill. The model bioprinters are made from ordinary materials— cardboard, dowels, wood, spools, duct tape, zip ties and glue (constructed by the teacher or the students)—and use squeeze bags of icing to lay down tissue layers. Student groups apply what they learned about biological tissue composition and tissue engineering in the associated lesson to design and fabricate model replacement tissues. They tangibly learn about the technical aspects and challenges of 3D bioprinting technology, as well as great detail about the complex cellular composition of tissues. At activity end, teams present their prototype designs to the class.

Students learn about the current applications and limitations of 3D bioprinting, as well as its amazing future potential. This lesson, and its fun associated activity, provides a unique way to review and explore concepts such as differing cell functions, multicellular organism complexity, and engineering design steps. As introduced through a PowerPoint® presentation, students learn about three different types of bioprinters, with a focus on the extrusion model. Then they learn the basics of tissue engineering and the steps to design printed tissues. This background information prepares students to conduct the associated activity in which they use mock-3D bioprinters composed of a desktop setup that uses bags of icing to “bioprint” replacement skin, bone and muscle for a fictitious trauma patient, Bill. A pre/post-quiz is also provided.