The aim of this study is to determine the students' views on the structure and parts of the heart by allowing the students to compare the real heart and the heart drawings in the textbooks with “Diagnose Your Heart” activity prepared according to the life-based learning approach. The study was conducted with 11th grade students attending an Anatolian High School in Samsun during the 2018 - 2019 academic years. The study group consisted of 30 students who participated in “Diagnose Your Heart” where heart dissection was performed. In the selection of the students, an appropriate sampling method was used which allows the researchers to reach easily. Open-ended questions were prepared as a data collection tool. The open-ended questions were read to experts from other fields and asked whether they were understandable. In addition, a faculty member who specializes in biology education received their opinions on the questions. Necessary arrangements were made in line with the opinions of the experts. Data collection tool consists of 5 open-ended questions. With the final data collection tool, students were asked open-ended questions to express whether there is a difference between the heart drawings in the books and the actual heart dissected. During the activity, dissection of a real mammalian heart was performed with the students and the students were examined in detail. For this purpose, the sheep heart, which has been provided previously, has been shown primarily to the outer parts and aortic vein, veins and coronary vessels. Then the sheep's heart was cut properly and the ventricles, atria and valves were shown to the students. At these stages, the students were given the opportunity to examine the parts of the heart closely by touching them. While heart dissection activity, structure, and parts of the heart are shown in detail, students were asked to compare the actual heart with the heart drawings in the textbooks. The students comparing the actual heart and the heart drawings in the books were asked to answer open-ended questions prepared by the researchers. Students' answers to open-ended questions were analyzed. First of all, the answers of all students to all questions were read and analyzed. During the analysis, the answers of the students to each question were coded separately and assigned to the data sections obtained from the students' answers. Later similar codes were categorized under a theme. Sub-themes were created in case of need. The frequency and percentages of the data categorized by analysis were determined and tables were created. The codes with the highest frequency are sorted to the least and the tables are finalized. The obtained tables were interpreted by including the sample student data sections of the codes obtained result of the analyses. As a result, when the data obtained from the students were analyzed, they stated that there were some differences between the heart drawings drawn in the books of the other students and the real heart except for 2 students. Students who think that there is a difference between the drawing and the real heart stated that the structures in the actual heart appear more clearly, that they are more detailed, and that structures such as the valve and the atrium look different. Students stated that fibrous structures that connect the heart valves to the heart muscles, aortic artery, heart atrium and valves on the actual heart are the most attention heart structures. When asked what differences were seen in the right and left ventricular walls in the examined heart, the students stated that “Left ventricle is thicker than right ventricle” ”Aortic and pulmonary arteries are different in right and left ventricle” “Left ventricle is larger than right ventricle”. When asked what kind of differences between arteries and veins; “The arteries are thicker than the veins”, “The veins are below, the arteries are up”, “The arteries and veins are connected to different atria and ventricles”. When the students were asked what kind of changes in their heart-related information after the activity, 3 students stated that there was no change in their information, while the other students learned that they understood the structure of the heart better ” they saw the heart in more detail” and that the real heart was different from drawing. In this study conducted with students, in addition to making use of twodimensional drawings in books in teaching different structures and subjects of biology from the data obtained, enriching teaching with real materials as much as possible will enable students to learn more meaningfully and easily. The appropriateness of the teaching methods used in science education to the subjects to be taught is very important. Otherwise, the student will have difficulty in understanding and making sense of the subject.