Regeneration is the natural process of regaining or replacing missing/damaged cells, tissues, organs, or body parts. The newly formed parts are fully functional, observed in plants and animals. Did you know that the science of regeneration could help us discover advanced avenues in health sciences, like how to delay aging and develop effective drugs?
The question here arises what organisms are capable of regeneration? Interestingly, all living beings can regenerate some parts (tissues or organs) of the body; however, the extent of the process varies among different organisms. For instance, a hydra (a freshwater animal) could develop two functional bodies after being cut into two halves. The Mexican salamander or axolotl can regain lost organs, limbs, or body parts.
Stem cells are specialized undifferentiated cells crucial in the process of regeneration. Three primary types of stem cells develop into different types of cells/tissues/organs. These cells have the superpower of renewing themselves a million times. Blastema formation is initiated by a signaling cascade, which results in the dedifferentiation of the cells near the wound. A blastema is a cell aggregation of undifferentiated cells that can form whole organs or body parts. Blastemas are commonly found in embryos or regenerating wounds.
The intricacies of regeneration, like what a blastema is and the cell types, the concept of positional information, etc., make it a complex and tricky topic for students. Let’s discuss five practical solutions presented by Labster to make teaching these concepts easy.
Image from Labster's Regeneration Biology Virtual Lab.
Regeneration seems like a simple topic in middle school. Still, at the high school/college level, the details and complexities of the subject increase, making students feel overwhelmed about the topic. Following are some reasons that make studying regeneration biology an exhaustive task for most students.
The morphological aspect of regeneration is visible to the naked eye, but the physiology (set of events leading to the formation of a lost part) occurs at the molecular level. Therefore, the changes undergone by blastema cells could only be seen using a microscope. Students need to know the use of microscopes along with tissue preparation techniques to understand these cellular processes.
Limb regeneration in axolotl is an extensively researched topic in regeneration biology. The axolotl shows a unique behavior - complete regeneration of limbs independent of the site or axis of injury. The set of events leading to the formation of limbs (again) is a complex process, making it a tricky topic to teach and understand.
The amputated site is covered by wound epithelium within a few hours of injury. After a couple of days, the nerve cells intervene and form an apical epithelial cap. It acts as a specialized signaling center that regulates the synthesis of molecules essential in the dedifferentiation and proliferation of cells into specialized limb progenitor cells (blastema cells). The pattern of missing limbs is formed through the interaction of specialized cells (from opposite limb axes) in a specific area leading to cell re-differentiation; as a result, a fully functional new limb forms at the injury or amputation. The process of blastema formation is unique in each group of organisms; for instance, in planarians, the proliferated neoblasts forms blastema, while in insects and crustaceans, the epidermal cells move towards the site of amputation/injury undergo dedifferentiation and form a wound blastema.
The concepts get more complicated as we further discuss the topic in detail; therefore, it is natural for teachers or students to find this a tricky subject.
The regeneration process is unique for each group of organisms and follows specific morphogenetic patterns. The different types of stem cells, their origin, blastema cells, etc., are a crucial part of this topic. Moreover, the idea of positional information claims that cells receive positional values in the same manner that a coordinate system does, which they interpret by evolving in specific ways to produce spatial patterns. Students feel dazed as they have to learn about these additional aspects.
Let's discuss five efficient and practical strategies to help you make regeneration biology a more straightforward topic for students.
Biological phenomena like regeneration are significant in improving life/health standards; therefore, many people have invested their lives in uncovering the mysteries behind this process. A brief trip to the past would help students understand the importance of this topic.
Scientists started experimental studies in the 18th century and realized that the process and extent of regeneration vary between animal taxa. There is a close relationship between regeneration and evolution that is still uncertain despite all the extensive research.
August Weismann (1893, 1899) explored the difference in the capacity of regeneration among animals in comparison to evolution. He purported that this ability is an adaptive trait associated with phylogenetic alterations. He also highlighted the significance of anatomical and physiological aspects and the severity of organ damage in the success rate of organ regeneration. Arthur Edwin Needham (1952) remarked that some environmental conditions (like aquatic habitats) are more favorable for regeneration. He observed that the loss of organs is not always compensated by regeneration; instead, there are other less expensive adaptive mechanisms like enhanced mobility or improved breeding capacity.
The origin of regeneration is often debated as some experts believe it’s a primary ability while others think it to be a trait in primitive organisms developed along multicellularity. The most reasonable explanation is that it is a programmed set of events or morphogenetic processes consisting of asexual reproduction, growth, and embryogenesis. Vorontsova and Liosner (1960) discussed different types of regeneration with specific evolution. Bely and Nyberg 2010 studied their reports and conducted further research to understand different types of regeneration, like regeneration of tissues, organs, or the entire body.
This topic's mystical nature could be used to advantage as students are usually interested in learning about organisms that could regrow injured parts. Share some awe-inspiring facts that would help students acquire knowledge and make them intrigued to learn more. Dome facts about regeneration biology are as follows:
The potential for regeneration declines with age progressions.
Aquatic species like sea urchins can regenerate throughout life.
Scientists are trying to understand human aging through regeneration.
It is believed that kidneys lost their potential of neo nephrogenesis through the course of evolution as the organ became more complicated.
Studies revealed that renal progenitor cells (RPCs) are found in lower vertebrates like insects and fish and mammals like rats and humans. It explains the regeneration potential in kidneys.
Lizards can grow back the lost parts of their tail or the entire tail. The amputated tail wiggles to give the lizard a chance to run away from the predator. It usually takes about nine months for a lizard to grow a tail ultimately.
Flatworms (planarians) could grow an entirely new individual from each cut piece. Likewise, if a sea cucumber is cut into several parts, each part will become a new organism.
Sharks can potentially replace lost teeth repeatedly; in one lifetime could replace as many as 24,000 teeth.
The antlers in deer have a unique property of annual regeneration. However, male caribou species (reindeer) have antlers growing a quarter-inch daily.
Student-teacher interaction is vital to keep your class engaged in the classroom. One way to make students participate in the lecture is to ask brainstorming questions. The questions should be straightforward and simple to answer. Reviewing the ideas relevant to the topic that students have already studied in previous grades is appropriate. Some questions on regeneration biology that you might include at the start of your lesson plan are as follows:
What happens if you accidentally cut your finger?
Can you recall the role of stem cells?
Do you think plants can regenerate?
Do you think animals can regenerate?
What would happen if you cut hydra into two halves?
What happens to a salamander if it loses its tail?
Can axolotls regenerate their head?
Make a worksheet with closed-ended questions (yes or no) related to axolotl regeneration. Such questions before starting the lesson would spark interest among students. They’ll be motivated to learn more. Also, this activity won’t take too much time and is appropriate for high school/college students. Some questions that could be included in this activity are as follows:
Is it possible for the axolotl to regenerate heat?
A juvenile axolotl can regenerate a limb in approximately 40-50 days.
Regeneration ability of axolotl increases with time.
A virtual laboratory simulation is a great way to teach muscle tissue: structure and function. At Labster, we're dedicated to delivering fully interactive advanced laboratory simulations that utilize gamification elements like storytelling and scoring systems inside an immersive and engaging 3D universe.
Check out Labster's simulations for Regeneration Biology Virtual Lab. You’ll get to join Dr. Prometheus in his research to learn why some wounds can regenerate and others cannot and how it translates into different treatments in a medical ward. You will experiment with axolotls in the Regeneration Biology lab to discover the critical steps required for regeneration and cellular particularities of the blastema.
Please take a look at the following snippets taken from the Labster simulations or get in touch to find out how you can start using virtual labs with your students.