Background: The major membrane currents responsible for sinoatrial (SA) rhythm generation are generally studied in isolated cardiac cells using electrophysiological tools. Such studies are resource and labor-intensive. Materials and Methods: Here, we have studied four major currents in isolated rat heart preparations, perfused in Langendorff mode, and demonstrate that this is a good preparation for such studies. Heart rates of isolated perfused rat hearts were recorded using surface electrocardiogram before and after perfusion with drugs and solutions that affect the four major currents responsible for SA rhythm generation. Results: The rates of whole isolated hearts beating with SA rhythm decreased with cesium and decreased by about half with ivabradine, both blockers of the funny current (I f ). Importantly, the rhythm was not abolished even with a high dose of ivabradine at which total blockade of I f is expected. The rate was not affected by nickel, a blocker of T-type calcium current. The SA rhythm was abolished by the reduction or removal of sodium from the perfusate (interventions that inhibit the calcium-extrusive mode of the sodium-calcium exchanger) or by nifedipine, the L-type calcium channel blocker. Discussion: The inferences made based on these observations are (a) I f contributes significantly to pacemaking, (b) I CaT does not play a role and (c) I NCX and I CaL are obligatory rhythm-generating currents in the SA node. Cyclical calcium release from SR during diastole (the calcium clock), responsible for driving I NCX in its forward mode is probably a phenomenon independent of membrane events, as total I f blockade did not abolish rhythm generation. These results corroborate with published literature where most studies were done on single cells.

The major membrane currents responsible for sinoatrial and idioventricular rhythm-generation were studied in isolated rat heart preparations, perfused in Langendorff mode. The rates of whole isolated hearts beating with sinoatrial rhythm decreased with cesium and ivabradine, both blockers of the funny current, and were not affected by nickel, at a dose which blocks T-type calcium current. The sinoatrial rhythm was completely abolished by reduction or removal of sodium from the perfusate (interventions that inhibit calcium-extrusive mode of the sodium/calcium exchanger), or by nifedipine, an L-type calcium channel blocker. Idioventricular rhythm, however, was arrested only by reduction of sodium in the perfusate. Ivabradine reduced the idioventricular rate, nickel did not cause any change, while nifedipine in some cases increased it. The inferences made based on these observations are that INCX and ICaL are obligatory rhythm-generating currents in the sinoatrial node, while INCX is the only obligatory mechanism for an idioventricular rhythm. The funny current is not an obligatory requirement for sinoatrial as well as idioventricular rhythm-generation. However, it enhances the frequency of LCRs. Our results in the isolated whole heart are in corroboration with results from isolated cells.

Large language models (LLMs) are rapidly becoming an important foundation model that has infiltrated our daily lives in many ways. The release of GPT-3 and GPT-4, a LLM that is capable of natural language processing (NLP) that has been trained on terabytes of text data through transfer learning to apply knowledge gained from a previous task to solve a different but related problem, immediately captured the attention of the medical field to investigate how LLMs can be used to process and interpret electronic health records and to streamline clinical writing.1 NLP models have traditionally been used mainly as diagnostic aids in healthcare. Its use generally requires supervised learning on manually labeled and training datasets with a huge involvement of time from healthcare professionals.2 NLP models often lack precision, accuracy and mostly only accessible by the developers. Recent LLMs with their transformer and reinforcement learning with human feedback, have enabled better precision in text generation. The advancement of GPT-3 (Generative Pre-Trained Transformer, commonly known as ChatGPT) demonstrated that LLMs can rapidly adapt to new tasks resulting in better generalization. Also, ChatGPT has a simple interface, which has enabled broad adoption and use. Having such a versatile and user-friendly tool at our fingertips means that we can adapt to use LLMs for basic tasks such as generating clinical reports, providing clinical support, or to synthesize patient data from multiple sources. We have used this case report as an opportunity to demonstrate the practicality of ChatGPT in basic writing tasks in a clinical context. This case report is obtained from two teaching videos uploaded by TTMedcastTraining Texas Tech University on YouTube. The two videos are of a patient called Jonathan who presented with bilateral knee pain with a history of sickle cell disease. One video is the bedside presentation of the patient by a medical intern, another is a group discussion of treatment plans for this patient. Since GPT-3 can only deal with text input, we have downloaded the transcript from each video. The transcripts sometimes contain people talking at the same time, filler words, mispronounced words, or incomplete sentences. Unaltered transcripts were submitted to ChatGPT separately for interpretation. The workflow of using ChatGPT to generate the case report is summarized in Figure 1. We fed the transcript of Video 1 into ChatGPT and asked it to write a case report from it (Case Report 1). Then, we used the transcript of Video 2 to create Case Report 2. ChatGPT was asked to combine the two reports without summarizing and offer a diagnosis and a treatment plan. We also asked ChatGPT to write the final case report in the style for the New England Journal of Medicine. This process took around 1.5 h, including time the authors spent watching the videos. The full case report is found in Supporting Information, ChatGPT's Case Report. The first author, an attending physician in pediatric surgery, was also asked to study the videos and write a case report based on the two videos. Due to a heavy workload and varied schedule from his work, it took several attempts and in total roughly 4 h to complete. This report is found in Supporting Information, Physician's Case Report. He was also asked if he agreed with the diagnosis and treatment plan provided by ChatGPT. After careful research on sickle cell disease and its presentation, the first author agreed with the diagnosis and treatment plans. To compare the quality of writing, we have asked three physicians to rate the two case reports according to a modified version of The Joanna Briggs Institute Critical Appraisal Checklist for Case Reports.3 All three physicians gave the two reports similar scores of 5.7/8 and 6/8 for ChatGPT's and physician's report respectively. The most common comment regarding ChatGPT's report is the lack of the patient's past medical history while this information is more evident in the physician's report. Detailed comments are found in Supporting Information. This study is a good example of how ChatGPT can be used effectively to perform simple writing tasks in a clinical setting when clinicians record their cases to write up later and how easy it is to use ChatGPT to synthesize data from multiple sources and to provide medical support. However, before ChatGPT can be used in day-to-day practice, several important points need to be raised. ChatGPT requires very detailed and specific information to write the final case report (the chat history detailing the prompts and the separate case reports generated is available in Supplementary Materials). Although the first report was not perfect, it is possible to refine the report by requesting ChatGPT to incorporate additional information. With practice, users will be familiarized with prompt strategies that will generate the desired outputs. In this case report, our prompts were clear and simple. We specified that the original text was a “transcript from a video” so that the format of the text input was understood. We employed strong and meaningful prompts such as “write,” “incorporate” and “combine” and qualified our request to “not summarize” the information given. In addition, we wanted to generate a case report in a format that most clinicians are familiar with reading. To this end, we prompted with the specific output format of “New England Journal of Medicine.” One important point to highlight is that ChatGPT can be used to interpret incomplete medical data by offering diagnostic assessments and treatment plans based on medical history and patient symptoms. We believe that ChatGPT will be a useful assistant that can be used to complete time-consuming writing tasks, even when clinical data was partially missing. It is important to note that ChatGPT can provide ideas, but it cannot replace a clinician's knowledge. In-depth knowledge of their cases and the diseases being treated is absolutely necessary to ensure credibility of generated text and to avoid misinterpretation from the LLM. Clinicians must dedicate time to fact check generated reports soon after attending a case to avoid confusing generated material with actual medical records.4 It remains the sole responsibility of the attending clinician to ensure patient data accuracy and privacy, and that they make the final diagnostic and treatment decisions to avoid any legal and ethical issues that may arise from incorrectly LLM-generated patient data.5 With the advancement of fine-tuned medical LLMs such as GatorTron (a clinical LLM that is trained on deidentified clinical text to process and interpret electronic health records) and Google's Med-PaLM 2 (LLM that is billed to more accurately and safely answer medical questions), we can expect to see much more AI-generated text in every area of medicine. We must, however, remember that medicine is an interpersonal process, and the interaction and communication between doctor and patient remains irreplaceable. We can use LLMs to enhance the ability of practitioners to improve accuracy and precision whilst empowering patients with greater autonomy, but we must be mindful of ethical considerations of the integration of LLMs in medical practice. In conclusion, ChatGPT has the potential to be a valuable tool for clinicians in generating case reports in a timely manner. However, its use requires practice and willingness to dedicate time to verify the accuracy of generated data using a clinician's expertise and knowledge. Yongqin Ye: Data curation (equal); formal analysis (equal); methodology (equal); validation (equal); writing—review and editing (equal). Shuvam Sarkar: Data curation (equal); formal analysis (equal); validation (equal); writing—review and editing (equal). Anand Bhaskar: Data curation (equal); formal analysis (equal); validation (equal); writing—review and editing (equal). Brian Tomlinson: Data curation (equal); formal analysis (equal); validation (equal); writing—review and editing (equal). Olivia Monteiro: Conceptualization (equal); data curation (equal); formal analysis (equal); methodology (equal); project administration (equal); resources (equal); software (equal); supervision (equal); validation (equal); writing—original draft (equal); writing—review and editing (equal). All authors have read and approved the final manuscript. The case report in this study is generated with ChatGPT: OpenAI. (2023). ChatGPT [Large language model]. https://chat.openai.com/chat The authors declare no conflicts of interest. Not applicable. The source videos are at https://youtu.be/PrxpxtpbMt0 and https://youtu.be/RJQPA2zFobE. The data that support the findings of this study are openly available in our Supporting Information. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Emerging viral infections are a ceaseless challenge and remain a global public health concern. The world has not yet come back to normal from the devastating effects of the highly contagious and pathogenic novel coronavirus, or Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Olfactory and taste dysfunction is common in patients infected by the novel coronavirus. In light of the emergence of different coronavirus variants, it is important to update the prevalence and pathophysiology of these side effects. In this review, articles published on the prevalence of olfactory and taste dysfunction from coronavirus disease (COVID-19) and their possible pathophysiologic mechanisms have been reviewed and reported. The modulatory role of different SARS-CoV-2 variants on the chemical senses is then described. The clinical relevance of chemical sense disorder and its long-term morbidity and management is also discussed.

LabChart data file of fatigue and recovery experiment. The file can be opened by using LabChart reader provided freely by ADInstruments, Australia at https://www.adinstruments.com/products/labchart-reader.

LabChart data file of treppe experiment. The file can be opened by using LabChart reader provided freely by ADInstruments, Australia at https://www.adinstruments.com/products/labchart-reader.

Cleistanthus collinus leaf extracts are consumed for suicidal purposes in southern India. The boiled decoction is known to be more toxic than the fresh leaf juice. Although several compounds have been isolated and their toxicity tested, controversy remains as to which compounds are responsible for the high level of toxicity of C. collinus. We report herein that cleistanthoside A is the major toxin in the boiled aqueous extract of fresh leaves and causes death in rats in small doses. The toxicity of the boiled extract prepared in the manner described can be attributed entirely to cleistanthoside A. Cleistanthin A could also be isolated from the boiled extract, albeit in trace amounts. As hypotension not responding to vasoconstrictors is the cause of death in patients who have consumed the boiled extract, effects of cleistanthoside A on the determinants of blood pressure, namely, force of cardiac contraction and vascular resistance, were tested in isolated organ experiments. Cleistanthoside A has a direct vasoconstrictor effect; however, it inhibits ventricular contractility. Therefore, the notion that the shock in C. collinus poisoning is of vascular origin must be considered carefully, and the possibility of cardiogenic shock must be studied. We present the crystal structure of cleistanthin A and show the potency of fast NMR methods (NOAH4-BSCN-NUS) in the full spectral assignment of cleistanthoside A as a real-world sample of a natural product. We also compare the results of the NOAH4-BSCN-NUS NMR experiments with conventional NMR methods.

This sourcebook update describes a variation of a previous sourcebook experiment that used isolated extensor digitorum longus muscle from mouse to teach skeletal muscle properties (Head SI, Arber MS. Adv Physiol Educ 37: 405-414, 2013). Gastrocnemius-sciatic nerve preparation in an anaesthetized rat was developed and muscle contractions were recorded in a computerized data acquisition system using an isometric force transducer. Teachers and students in physiology or biology can use this preparation to demonstrate skeletal muscle properties like simple muscle twitch, quantal summation, wave summation, superposition, incomplete tetanus, complete tetanus, treppe, fatigue, and length-tension relationship.

Patch-clamp electrophysiological recordings of neuronal activity require a large amount of space and equipment. The technique is difficult to master and not conducive to demonstration to more than a few medical students. Therefore, neurophysiological education is mostly limited to classroom-based pedagogies such as lectures. However, the demonstration of concepts such as changes in membrane potential and ion channel activity is best achieved with hands-on approaches. This article details an in silico activity suitable for large groups of medical students that demonstrates the key concepts in neurophysiology using the LabAXON simulation software. Learning activities in our practical include 1) measurements of voltage and time parameters of the neuronal action potential and its relationship to the Nernst potentials of Na+ and K+; 2) determination of the stimulus threshold to evoke action potentials; 3) demonstration of the refractory period of an action potential; and 4) voltage-clamp experiments to determine the current-voltage relationship of voltage-gated Na+ and K+ channels and the voltage dependence of, and recovery from, inactivation of voltage-gated Na+ channels. We emphasized the accuracy of quantitative measurements as well as the correct use of units. The level of difficulty of the activity can be altered through different multiple choice questions relating to material introduced in the associated lectures. This practical activity is suitable for different class sizes and is adaptable for delivery with online platforms. Student feedback showed that the students felt the activity helped them consolidate their understanding of the lecture material.

Practical demonstration of cardiomyocyte function requires substantial preparation, a source of freshly isolated animal hearts, and specialized equipment. Even where such resources are available, it is not conducive for demonstration to any more than a few students at a time. These approaches are also not consistent with the 3R principle (replacement, reduction, and refinement) of ethical use of animals. We present an implementation of the LabHEART software, developed by Donald Bers and Jose Puglisi, for medical students. Prior to the activity, students had lectures covering the physiological and pharmacological aspects of cardiac excitation-contraction (EC) coupling. We used this problem-based activity to help students consolidate their knowledge and to allow a hands-on approach to explore the key features of EC coupling. Students simulate and measure action potentials, intracellular calcium changes, and cardiomyocyte contraction. They also apply drugs that target ion channels (e.g., nifedipine or tetrodotoxin) or sympathetic input (using isoproterenol) and explore changes to EC coupling. Furthermore, by modifying the biophysical parameters of key ion channels involved in the electrical activity of the heart, students also explore the effect of channelopathies such as long QT syndromes. We describe approaches to implement this activity in a flipped classroom format, with recorded lecture materials provided ahead of the practical to facilitate active learning. We also describe our experiences implementing this activity online. The content and difficulty of the activity can be altered to suit individual courses and is also amenable to promote peer-driven learning.

This paper describes the process involved in conducting an online spirometry practical through Zoom. The teacher demonstrated the practical from the medical school, and the students observed the procedure from the comfort of their own homes. Students were able to analyze the graphs captured in the teacher's laptop by remotely controlling the teacher’s laptop. This method may be useful for places where face-to-face classes are suspended due to the COVID-19 pandemic.

IlluminationsA simple model for demonstrating the factors affecting glomerular filtration rateAnand Bhaskar and Vinay OommenAnand BhaskarDepartment of Physiology, Christian Medical College, Vellore, Tamil Nadu, India and Vinay OommenDepartment of Physiology, Christian Medical College, Vellore, Tamil Nadu, IndiaPublished Online:15 May 2018https://doi.org/10.1152/advan.00195.2017MoreSectionsSupplemental MaterialPDF (824 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat INTRODUCTIONGlomerular filtration, an important part of renal function, helps in eliminating waste materials and in maintaining fluid and electrolyte balance. The rate of filtration, or the glomerular filtration rate (GFR), is determined by the equation GFR = Kf × net filtration pressure, where Kf is the filtration coefficient. The Kf is directly proportional to the surface area of the filtering membrane and its hydraulic conductivity. The net filtration pressure is determined by the balance of the Starling forces (the hydrostatic pressure and the oncotic pressure within the glomerular capillaries and Bowman's capsule). The glomerular capillary hydrostatic pressure is affected by the afferent and efferent arteriolar resistance and the renal artery pressure (3). An increase in the afferent arteriolar diameter (decrease in resistance) causes an increase in the glomerular capillary hydrostatic pressure and an increase in GFR. A decrease in the diameter of the afferent arteriole has the opposite effect. An increase in the efferent arteriolar diameter (decrease in resistance) causes a decrease in the glomerular capillary hydrostatic pressure and a decrease in GFR. A decrease in the diameter of the efferent arteriole has the opposite effect. An increase in renal arterial pressure (or renal blood flow) causes an increase in GFR. A reduction in renal arterial pressure (or renal blood flow) will have the opposite effect (1).Pictures are often used to teach the concept of glomerular filtration in a didactic setting, and students have to visualize the various factors affecting glomerular filtration. Animations with user-changeable parameters have been recently described to teach the regulation of glomerular filtration (2). Physical models that demonstrate the factors affecting GFR are not available. Renal physiology is also an area where practical experimentation is not common. We felt that a simple physical model would further assist students in understanding this concept, as they could directly observe the effect of changing factors affecting the GFR. This article describes the construction of such a model, its presentation, and the assessment of the student feedback regarding the usefulness of this activity in a laboratory session in the first year of medical training.Construction of the ModelThe model was constructed using commonly available plumbing supplies given below (Fig. 1).Fig. 1.The constructed model connected to a tap. The shower head (representing the glomerular capillaries) is connected to two ball valves through a T-junction. Valve 1 represents the afferent arteriole. Valve 2 represents the efferent arteriole. Water filtered through the shower head represents the glomerular filtrate and is collected in beaker 1, representing Bowman's capsule. Water exiting the model represents the flow through the peritubular capillaries and is collected in beaker 2.Download figureDownload PowerPointTwo plastic ball valves (0.5-in. inner diameter)A piece of PVC pipe (0.5-in. inner diameter)One T-junction (0.5-in. inner diameter)A shower head with a replaceable cover. All of the holes in the shower head were plugged with Blu Tack on the inner surface of the cover, except for 15 holes. On some shower heads, the holes were drilled through to make the diameter of each hole wider.A piece of garden hoseBonding solutionTwo 2-liter beakers for measurementThe different components of the model were connected to each other using small pieces of PVC pipe. The shower head (representing the glomerular capillary where filtration happens) was connected to the vertical arm of the T-junction. The shower head was kept over a 2-liter beaker (beaker 1 representing Bowman's capsule) to collect the filtered water. The horizontal arms of the T-junction were connected to the two ball valves (representing the afferent and efferent arterioles with variable resistance). The first valve (valve 1) was connected via a hose to a tap (sink faucet). Water input to the model through the tap represented the renal plasma flow coming to the glomerular capillary. The second valve (valve 2) was connected to a hose to collect the unfiltered water. The unfiltered water (representing renal plasma flow in peritubular capillaries) was also collected in a 2-liter beaker (beaker 2). The connections between the pipes and valves and that between the pipes and T-junction were made stronger with the use of bonding solution. All of the water that was collected for measurement was stored in a tub for other uses to prevent a waste of water.Presentation of the Model and Experimental ProceduresThe model was presented to students studying in their first year of medical training in groups of 8–10 students each. This was done during a laboratory session. The students had already been exposed to a comprehensive 18-h module on renal physiology. The objective of using this model in a practical setting was to revise and clarify concepts that had been covered in the theory module. The presentation of the model and the experiments performed took ∼1 h.To begin with, the components of the model were described to the students. A handout explaining the different experiments to be performed was given to them (Supplemental Data S1; supplemental material are available in the data supplement online at the Advances web site). An initial demonstration on how to use the model was conducted by the instructor. Thereafter, the students performed the experiments in different groups simultaneously. Immediately after the session, an anonymous written feedback was obtained to assess the usefulness of this model in understanding the factors affecting the GFR.A total of five different experimental scenarios were tested by altering the following parameters: filtration area, hydraulic conductivity, the inflow, and the input and output valve resistances. Each of these scenarios corresponded to various possible physiological and pathological variations in the factors affecting the GFR.Baseline measurements.The tap was kept at midposition, with both input (valve 1) and output valves (valve 2) open to the midposition (45°). The shower head had 15 holes open, of normal diameter. All other holes were plugged with Blu Tack.Scenario 1: the effect of an increase in filtration area.The shower head was replaced with another having 30 holes of normal hole diameter, with all other parameters the same as in baseline measurements. This increase in filtration area is similar to what is seen with relaxation of the mesangial cells.Scenario 2: the effect of an increase in hydraulic conductivity.The shower head was replaced with a different shower head that had 15 holes, but of larger hole diameter, with all other parameters the same as in baseline measurements. This scenario demonstrates the effect of filtration pore size on the GFR.Scenario 3: the effect of a change in renal plasma flow.Measurements were taken with the tap completely open (increased flow) and open less than the midposition (decreased flow), with all other parameters the same as in baseline measurements. The change in flow in this scenario is similar to what is seen in conditions such as changes in cardiac output or blood pressure (assuming that the renal compensatory mechanisms that regulate GFR have not taken place).Scenario 4: change in afferent arteriolar resistance.Measurements were taken with the input valve (valve 1) more open (afferent arteriolar dilation) and less open (afferent arteriolar constriction) from the midposition, with all other parameters the same as in baseline measurements. The constriction in this scenario is similar to the afferent arteriolar constriction seen with sympathetic stimulation.Scenario 5: change in efferent arteriolar resistance.Measurements were taken with the output valve (valve 2) more open (efferent arteriolar dilation) and less open (efferent arteriolar constriction) from the midposition, with all other parameters the same as in baseline measurements. The constriction in this scenario is similar to a moderate constriction of the efferent arteriole caused by angiotensin II.In each scenario, students measured the volume of filtered water, which represented the glomerular filtrate, and the volume of water exiting the output valve (valve 2), which represented the peritubular capillary flow. All volumes were measured with the tap open for 5 s. Adding both volumes provided the total flow, which represented the renal plasma flow. Filtration fraction was obtained by dividing the filtered volume by the total volume. Students entered the collected values in a tabular column provided in the handout.Leaks in the system can affect the volumes measured. It is important to ensure that there no major leaks. It is also important to ensure that there are no fluctuations of water output through the tap.ResultsBaseline measurements were made with the shower head having 15 open holes of normal diameter.Use of a shower head with more holes or larger diameter holes resulted in an increase in filtration fraction with minimal change in total flow. This was expected because of an increase in the area of filtration and hydraulic conductivity. These are factors that affect the filtration coefficient of the filtration membrane.An increase or decrease in the flow from the tap resulted in a corresponding increase or decrease in filtered volume and total flow, with minimal change in filtration fraction. This corresponds to an effect of uncompensated change in renal plasma flow. In the body, however, myogenic mechanisms and tubuloglomerular feedback mechanisms compensate for the changes in flow to maintain glomerular filtration.An increase in input valve (valve 1) resistance (open less than midposition) resulted in a decrease in filtered volume and total flow, with minimal change in filtration fraction. This represented the effect of afferent arteriolar constriction. A decrease in input valve resistance had the opposite effect on filtered volume and total flow, with minimal change in filtration fraction.An increase in output valve (valve 2) resistance (open less than midposition) resulted in an increased in filtered volume, a decrease in total flow, and an increase in filtration fraction. This represented the effect of efferent arteriolar constriction. A decrease in output valve resistance had the opposite effect.FeedbackAnonymous, voluntary feedback was obtained from the students after the activity to assess the usefulness of the model. There were 61 of 100 students who provided this feedback. The feedback contained three questions. The first question assessed how easy it was to understand the model. The second question assessed how useful the model was in improving the understanding of factors affecting GFR. The third question was whether the students would recommend this model for future batches of students. The results of the feedback are shown in Fig. 2. Questions 1 and 3 used a five-point Likert scale. For question 2, students were permitted to choose more than one option. The feedback form is included as supplemental information (Supplemental Data S2). Permission was obtained from the Institutional Review Board, Christian Medical College, Vellore, to analyze and publish the student feedback.Fig. 2.Student feedback obtained after the laboratory session. A: student response on how easy the model was to understand. B: student response on the usefulness of the model. C: students recommendations on using the model for future batches of students. GFR, glomerular filtration rate.Download figureDownload PowerPointThe model was found to be easy to understand by 77% of students (mean score 3.93). There were 66% of students who recommended the model for future students (mean score 3.9). Most students reported the model as useful, for reviewing existing concepts. The model was also found useful in adding to existing knowledge and in clarifying concepts that they did not understand. Terms such as "creative," "innovative and entertaining," and "very useful" were some of the comments given by the students about the model and the experiment.LimitationsIn the presentation of this model, the size of each group was ∼8–10 due to infrastructure constraints. A group size of three to four would have been ideal.A constant flow through the tap was assumed. The changes in flow were modeled by opening the tap halfway and completely. In reality, there may have been variations in the flow during the period of collection. Ideally the tap outflow pressure would have been measured using a pressure gauge, and this reading could have been used to accurately adjust flow. However, for the sake of simplicity, the knob of the tap was used for this purpose.The different components of the model were not to scale, compared with the different parts of the nephron that they represented.ConclusionThe model described is easy to construct and is inexpensive. Students also reported it useful as a tool to revise and clarify concepts. It can, therefore, be used as an additional teaching tool to complement lecture in renal physiology or as part of a laboratory exercise.DISCLOSURESNo conflicts of interest, financial or otherwise, are declared by the authors.AUTHOR CONTRIBUTIONSA.B. and V.O. conceived and designed research; A.B. and V.O. performed experiments; A.B. and V.O. analyzed data; A.B. and V.O. interpreted results of experiments; A.B. and V.O. prepared figures; A.B. and V.O. drafted manuscript; A.B. and V.O. edited and revised manuscript; A.B. and V.O. approved final version of manuscript.ACKNOWLEDGMENTSPortions of this work were previously presented at the SIMEDUCON 2018 conference held at Christian Medical College, Vellore, India, on March 3, 2018.REFERENCES1. Barrett KE, Barman SM, Boitano S, Brooks H. Renal function and Micturition. In: Ganong's Review of Medical Physiology (25th ed.). New York: McGraw-Hill, 2016, p. 679.Google Scholar2. Gookin JL, McWhorter D, Vaden S, Posner L. Outcome assessment of a computer-animated model for learning about the regulation of glomerular filtration rate. Adv Physiol Educ 34: 97–105, 2010. doi:10.1152/advan.00012.2010. Link | ISI | Google Scholar3. Hall JE. Urine formation by the kidneys. I. Glomerular filtration, renal blood flow, and their control. In: Guyton and Hall Textbook of Medical Physiology (12th ed.). Philadelphia, PA: Saunders Elsevier, 2011, p. 315.Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: V. Oommen, Dept. of Physiology, Christian Medical College, Bagayam Campus, Vellore, Tamil Nadu 632002, India (e-mail: [email protected]ac.in).Supplemental data Data Collection Table - .docx (14 kb) Feedback Form - .docx (15 kb) Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Cited ByEngaging medical students and residents in nephrology education: an updated scoping review5 August 2021 | Journal of Nephrology, Vol. 35, No. 1Demystifying the Nephron: a Call to Action26 September 2021 | Current Pediatrics Reports, Vol. 9, No. 4Appraisal of a novel pedagogical approach to demonstrating neuromuscular transmission to medical studentsSareesh Naduvil Narayanan, Iffath Ahmed, Batul Saherawala, Fatmaelzahraa Foud, and Tarig Hakim Merghani11 August 2021 | Advances in Physiology Education, Vol. 45, No. 3Interactive Metabolism, a simple and robust active learning tool that improves the biochemistry knowledge of undergraduate studentsVitória Costa Pereira Lopes Alves de França and Wellington Ferreira Campos22 April 2021 | Advances in Physiology Education, Vol. 45, No. 2A simple hand mnemonic for teaching the cardiac cycleHui Bian, Yan Bian, Jun Li, Shilian Xu, Xiaoxia Shao, Jiao Li, and Boao Jiang10 December 2019 | Advances in Physiology Education, Vol. 44, No. 1Normal Physiology of Renal System28 June 2020 More from this issue > Volume 42Issue 2June 2018Pages 380-382Supplemental Information Copyright & PermissionsCopyright © 2018 the American Physiological Societyhttps://doi.org/10.1152/advan.00195.2017PubMed29761711History Received 27 December 2017 Accepted 23 March 2018 Published online 15 May 2018 Published in print 1 June 2018 Metrics

IlluminationsChicken intestine: an alternative to the mammalian intestine for physiology experimentationNeetu Prince, Vinay Oommen, and Anand BhaskarNeetu PrinceDepartment of Physiology, Christian Medical College, Vellore, Tamil Nadu, India, Vinay OommenDepartment of Physiology, Christian Medical College, Vellore, Tamil Nadu, India, and Anand BhaskarDepartment of Physiology, Christian Medical College, Vellore, Tamil Nadu, IndiaPublished Online:15 May 2018https://doi.org/10.1152/advan.00031.2018MoreSectionsPDF (809 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat INTRODUCTIONTraining in physiology, be it at the school level, the graduate, or the postgraduate level, has traditionally involved animal experimentation. These demonstrations play a major role in supplementing didactic lectures, as well as making the subject more interesting. They also help future teachers acquire these experimental skills and techniques. However, a constant concern has been the large number of animals that have to be killed, either to demonstrate known phenomena, or to gain experimental skills. Many regulatory bodies have attempted to replace such experiments with alternatives, such as simulations, animations, and videos. Although useful to a certain degree, these replacements may not accurately represent the physiological phenomena they aim to recreate. Such commercial replacements are often also expensive. Institutions continuing to use animal experiments incur the high costs of maintaining animals in an animal facility or of procuring them from registered breeders for experimentation. Regulatory bodies have also gradually stripped the physiology curriculum at different levels of animal experimentation in different countries. This may result in graduates lacking critical skills that could assist them in their research or teaching in future years. In this scenario, using commonly available biological tissues for experimentation gains greater importance. We describe in this article how the chicken intestine, sourced from the slaughterhouse, can be used to demonstrate different physiological phenomena. The chicken intestine has been successfully used to perform bioassays for pharmacology training (2, 4).MATERIALS AND METHODSThe study was approved by both the institutional ethics as well as animal ethics committees. The chicken intestine was procured within 15 min of slaughter from a local slaughterhouse. About 10 cm of the duodenal loop, immediately after the gizzard, were cut and transported to the laboratory in cold physiological salt solution (PSS). The solution contained the following (in mM/l): 140 NaCl, 5.4 KCl, 1 CaCl2, 1 MgCl2, 5.5 glucose, and 5 HEPES, with a pH of 7.4.Intestinal contents were removed by flushing the intestine with PSS administered through a syringe. The fat and mesenteric tissue were removed, and a small portion of the intestine (~2 cm) was cut. A thread was tied to both ends of the segment without closing the lumen. One end of the strip was attached to the base of an isolated organ bath (15 ml in volume), and the other end to an isometric force transducer. The temperature of the organ bath was maintained at 37°C using a circulating water bath. The organ bath was continuously bubbled with oxygen. An initial stretch of 10 g (0.1 N) was given to the tissue. The peristaltic activity was recorded at 1 kHz using the PowerLab data acquisition system (AD Instruments) after force calibration. The experimental setup was similar to the one described by Montgomery et al. (3). Normal contractions were recorded for 15 min. Thereafter, the effect of different drugs and chemicals was noted. The interventions used were the addition of 1 μM acetylcholine, 10 μM adrenaline, 25 μM histamine, 5 mM calcium, 50 mM potassium, 2.5 mM barium, and 10 μM atropine, followed by 1 μM acetylcholine and 50 mM potassium. In each case, after the addition of the drug/chemical to the organ bath, the effects were recorded for 15 min. After each intervention, the solution was removed, and the tissue was washed with PSS three times. Normal contractions were recorded again for 15 min before the next intervention. IgorPro version 5.0.4.8 (WaveMetrics) was used for preparing the graphs of the experiments performed. Three sets of experiments were performed (using tissue from three different chickens). Representative tracings showing the effects seen are presented in results below.RESULTSAcetylcholine (1 μM) produced a marked increase in the basal tension (Fig. 1A). Adrenaline (10 μM) abolished peristaltic activity and reduced the basal tension (Fig. 1B). Pretreatment of the tissue with atropine (10 μM) abolished the increase in basal tension caused by 1 μM acetylcholine. The subsequent addition of high potassium (50 mM) caused a large increase in basal tension, showing that the tissue was alive (Fig. 1C). Basal tension was also increased by high calcium (5 mM), 2.5 mM barium, high potassium (50 mM), and 25 µM histamine (Fig. 2).Fig. 1.The effect of drugs on the basal tension and peristaltic activity of the isolated chicken intestine. A: the effect of 1 µM acetylcholine. B: the effect of 10 µM adrenaline. C: the effect of 10 µM atropine, followed by 1 µM acetylcholine and 50 mM potassium.Download figureDownload PowerPointFig. 2.The effect of drugs and chemicals on the basal tension and peristaltic activity of the isolated chicken intestine. A: the effect of 5 mM calcium. B: the effect of 2.5 mM barium. C: the effect of 50 mM potassium. D: the effect of 25 µM histamine.Download figureDownload PowerPointConclusion.We have observed that the responses of the chicken intestine to the drugs and chemicals used was similar to the responses that have been described in mammalian tissue (3). We have found that the tissue was easy to use and robust enough to allow continuous recordings for 5 h. The tissue was large in size and could be easily mounted in the organ bath. For our experiments, only the initial segment of the intestine was used. However, from one chicken, it is possible to obtain a large number of segments, if simultaneous experiments need to be performed. The chicken intestine is widely available and is often discarded as animal waste. It can be easily obtained at little or no cost. More importantly, as no animal needs to be slaughtered exclusively for this purpose, the use of the chicken intestine can help in reducing the number of laboratory animals used for educational purposes. This is in alignment with the three “R’s” of the ethical use of animals, i.e., refine, reduce, and replace (1). Such experiments can be a step toward preserving and enhancing animal experimentation skills in physiology.DISCLOSURESNo conflicts of interest, financial or otherwise, are declared by the authors.AUTHOR CONTRIBUTIONSN.P. and A.B. performed experiments; N.P., V.O., and A.B. analyzed data; N.P., V.O., and A.B. interpreted results of experiments; N.P. and A.B. drafted manuscript; N.P., V.O., and A.B. edited and revised manuscript; N.P., V.O., and A.B. approved final version of manuscript; V.O. and A.B. conceived and designed research; V.O. and A.B. prepared figures.ACKNOWLEDGMENTSWe thank the Christian Medical College, Vellore for funding this study.Portions of this work were previously presented at the SIMEDUCON 2018 conference held at Christian Medical College, Vellore, India, on March 3, 2018.REFERENCES1. Flecknell P. Replacement, reduction and refinement. ALTEX 19: 73–78, 2002. PubMed | Google Scholar2. Jain G, Bodakse SH, Namdev K, Rajput MS, Mishra S. Development of an ex vivo model for pharmacological experimentation on isolated tissue preparation. J Adv Pharm Technol Res 3: 176–181, 2012. doi:10.4103/2231-4040.101013. Crossref | PubMed | Google Scholar3. Montgomery LEA, Tansey EA, Johnson CD, Roe SM, Quinn JG. Autonomic modification of intestinal smooth muscle contractility. Adv Physiol Educ 40: 104–109, 2016. doi:10.1152/advan.00038.2015. Link | ISI | Google Scholar4. Nirmala P, Elandevan K, Chidambaram N, Santhakumari AS. Isolated chick ileum for bioassay of acetylcholine. Indian J Pharmacol 45: 312–313, 2013. doi:10.4103/0253-7613.111927. Crossref | PubMed | ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: A. Bhaskar, Dept. of Physiology, Christian Medical College, Vellore, Tamil Nadu 632002, India (e-mail: [email protected]com). Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Collections Cited ByThe CAM Model—Q&A with Experts28 December 2022 | Cancers, Vol. 15, No. 1Combined Use of Bacillus subtilis yb-114,246 and Bacillus licheniformis yb-214,245 Improves Body Growth Performance of Chinese Huainan Partridge Shank Chickens by Enhancing Intestinal Digestive Profiles11 August 2020 | Probiotics and Antimicrobial Proteins, Vol. 13, No. 2Predicting human glucose response curve using an engineered small intestine system in combination with mathematical modelingJournal of Food Engineering, Vol. 293 More from this issue > Volume 42Issue 2June 2018Pages 387-389 Copyright & PermissionsCopyright © 2018 the American Physiological Societyhttps://doi.org/10.1152/advan.00031.2018PubMed29761719History Received 16 February 2018 Accepted 27 April 2018 Published online 15 May 2018 Published in print 1 June 2018 Metrics

IlluminationsPumping the pulse: a bicycle pump to simulate the arterial pulse waveformSajal Clarence Singh, Anand Bhaskar, and Vinay OommenSajal Clarence SinghDepartment of Physiology, Christian Medical College, Vellore, Tamil Nadu, India, Anand BhaskarDepartment of Physiology, Christian Medical College, Vellore, Tamil Nadu, India, and Vinay OommenDepartment of Physiology, Christian Medical College, Vellore, Tamil Nadu, IndiaPublished Online:04 Apr 2018https://doi.org/10.1152/advan.00004.2018MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat INTRODUCTIONThe teaching of the cardiovascular system often involves both didactic lectures and practical sessions. During lectures, concepts such as systolic, diastolic, and pulse pressures are often discussed using textbook figures. The examination of the pulse is commonly demonstrated in a practical setting by examining oneself or a volunteer. Changes in the pulse rate, such as an increase in rate, can be demonstrated in these sessions by making the subject exercise. Other changes in the pulse, such as bradycardia and low-volume and high-volume pulses are usually discussed theoretically.Didactic teaching of the cardiovascular system can be made more interesting with the help of simple experiments that can be demonstrated in the classroom setting. Many educators have used analogies and models to demonstrate concepts of cardiovascular function. This includes the water tower analogy (8); using bottles and valves (7); syringes, balloons, and tubing (6); using a group dynamic activity (2); a hand pump activity (5); using singing card beepers (1); pulse plethysmographs (3); and using water supply, pressure transducers, and flow sensors to model hemodynamics (4).This paper describes a live demonstration of the arterial pulse waveform using a bicycle pump and a pressure transducer, used in a classroom setting.Materials required.Bicycle pumpSilicone tubing (5-mm inner diameter)Pressure transducerData acquisition systemComputer/laptopConstruction of the model.The bicycle pump was connected to the pressure transducer by means of a soft silicone tubing (~2 m in length) and appropriate connectors (Fig. 1). The pressure transducer used was a commercially available intra-arterial blood pressure transducer (iPex pressure monitoring kit, BL Life Sciences). The pressure transducer was connected to the data acquisition system through a preamplifier. For the described experiments, a data acquisition system and software that were developed in house were used (CMCdaq, developed by the Departments of Bioengineering and Physiology, Christian Medical College, Vellore). These experiments can also be performed using other commercially available pressure transducers and data acquisition systems.Fig. 1.A: schematic of the experimental setup showing the bicycle pump connected to a pressure transducer through a silicone tube. The data were collected with the help of a data acquisition system. The silicone tube was pressed against the table to feel the expansion of the tube with each pumping cycle. B: equipment used for the demonstration.Download figureDownload PowerPointThe action of the pump was observed on the screen as pressure changed. In this setup, the bicycle pump represented the heart (left ventricle), and the silicone tubing represented a peripheral artery.Care was taken to ensure that the air pressure from the pump remained well within the permissible limits of the pressure transducer to avoid damage to the equipment.The rate and the depth of pumping were controlled manually. The bicycle pump was operated at 1 push/s (60 pushes/min), and the waveform was observed on the screen. Care was taken to ensure that the pump piston was not pulled all the way upwards, so that the pressure did not fall to zero, but rather was maintained within a fixed range. The waveform thus obtained resembled that of an arterial blood pressure recording with a systolic and diastolic pressure.Presentation of the model.This model was presented to a group of 37 allied health students during the lecture series in cardiovascular physiology. This group consisted of students studying to become physiotherapists, occupational therapists, medical laboratory technicians, and neuro-electrophysiology technicians. The students had been introduced to the concepts of arterial pulse and blood pressure.The model was set up (Fig. 1) in the front of the class, and the data acquired during the acquisition were projected live on a screen to be visible to the entire class. The entire demonstration took ~30 min. The pumping was performed by the lecturer. A postgraduate student assisted in this demonstration.The demonstration involved the following scenarios.A normal recording was taken of the pressure waveform generated (Fig. 2). The pumping was carried out at a rate and force to ensure that the waveform did not return to the baseline. This tracing was used to discuss the concepts of systolic pressure, diastolic pressure, and pulse pressure.The students were asked to press the silicone tube with their fingers against the hard surface of the table, in a manner similar to a person palpating the pulse. The pumping was continued, and the students were able to feel the expansion of the tube with each pump cycle. This simulated the palpation of the normal pulse. Interested students took turns coming forward and palpating the expansion of the tube.For the next demonstration, the pumping was first carried out at 1 cycle every second. One of the students volunteered to keep time. After the baseline recording was made, the rate and force of pumping were altered. This was used to demonstrate common variations in the pulse waveform, such as tachycardia, bradycardia, a low-volume pulse, and a high-volume pulse (Fig. 2). The students observed the changes in waveforms on the screen.Fig. 2.Recordings made with a bicycle pump demonstrating the concepts of systolic pressure, diastolic pressure, pulse pressure, and variations in pulse rate and pulse volume.Download figureDownload PowerPointFeedback.An anonymous written feedback was collected from the students at the end of the lecture series on cardiovascular physiology. One of the questions that was asked of the students dealt with how useful this illustration was in understanding concepts in cardiovascular physiology. This was an open-ended question. The student responses were analyzed and grouped into three categories, “useful,” “not sure,” and “not useful” (Fig. 3). The response was overwhelmingly positive. A total of 31 students responded to this question. There were 83.9% (26 students) who felt that this model was useful; 9.7% (3 students) were neutral/not sure in their response; and 6.5% (2 students) felt that this was not useful. The students who found this model useful commented that this model helped them remember, kept them awake, and was interesting.Fig. 3.Compilation of feedback obtained from students (n) regarding the usefulness of the bicycle pump model in understanding concepts in cardiovascular physiology.Download figureDownload PowerPointOther possible uses.With practice in controlling the rate and force of pumping, we were able to make recordings that simulated other variations in pulse waveforms, such as pulsus bisferiens and pulsus alternans (Fig. 4). This was fairly easy to record once the person pumping got familiar with the system. This was not demonstrated to the students, however, as these topics were not discussed in the lecture series. This could be a useful and interesting activity for student groups of other streams.Fig. 4.Pressure recordings made with a bicycle pump and a pressure transducer to simulate abnormal pulsations.Download figureDownload PowerPointLimitations.The pulse waveform that is generated using the bicycle pump, although useful to discuss aspects of the pulse, is not a perfect reproduction of the arterial pulse waveform. This is something that has to be made clear to the students. However, with practice and timing of pumping, the waveform can be made to be nearly similar to the arterial pulse waveform.The waveforms record pressure changes. However, the waveforms commonly recorded with a pulse plethysmograph record volume changes. This distinction must be kept in mind while using this technique.The pressure recordings are due to pressure changes of the air column present in the tube. While this serves to demonstrate the pulse, it does differ from the blood pressure waveform, which deals with pressure changes in a noncompressible fluid.The pressures exerted while using a bicycle pump are far higher than the arterial pressures. To avoid confusing students, the pressure waveform was recorded as a voltage output from the pressure transducer, and the actual pressure values were not displayed.Conclusion.We found that the bicycle pump could be used to demonstrate the concepts of systolic, diastolic, and pulse pressures, and the various changes in the arterial pulse. The demonstration helped students feel the pulse and visualize the arterial pulse waveform and its variations. In departments in which a data acquisition system and a pressure transducer are available, the demonstration is easy to set up for use in a theory lecture and also permits student participation. The students were positive in their feedback, as this model was both interesting and helped them clarify their concepts. This simple activity can be used to make a didactic lecture more lively.DISCLOSURESNo conflicts of interest, financial or otherwise, are declared by the authors.AUTHOR CONTRIBUTIONSS.C.S. and V.O. conceived and designed research; S.C.S. and V.O. performed experiments; S.C.S., A.B., and V.O. analyzed data; S.C.S., A.B., and V.O. interpreted results of experiments; S.C.S., A.B., and V.O. drafted manuscript; S.C.S., A.B., and V.O. edited and revised manuscript; S.C.S., A.B., and V.O. approved final version of manuscript; A.B. and V.O. prepared figures.ACKNOWLEDGMENTSPortions of this study were previously presented at the SIMEDUCON conference held at Christian Medical College, Vellore, on March 3, 2018.REFERENCES1. Belušič G, Zupančič G. Singing greeting card beeper as a finger pulse sensor. Adv Physiol Educ 34: 90–92, 2010. doi:10.1152/advan.00015.2010. Link | ISI | Google Scholar2. Carvalho H. A group dynamic activity for learning the cardiac cycle and action potential. Adv Physiol Educ 35: 312–313, 2011. doi:10.1152/advan.00128.2010. Link | ISI | Google Scholar3. Djelić M, Mazić S, Žikić D. A novel laboratory approach for the demonstration of hemodynamic principles: the arterial blood flow reflection. Adv Physiol Educ 37: 321–326, 2013. doi:10.1152/advan.00176.2012. Link | ISI | Google Scholar4. Pontiga F, Gaytán SP. An experimental approach to the fundamental principles of hemodynamics. Adv Physiol Educ 29: 165–171, 2005. doi:10.1152/advan.00009.2005. Link | ISI | Google Scholar5. Pressley TA, Limson M, Byse M, Matyas ML. The healthy heart race: a short-duration, hands-on activity in cardiovascular physiology for museums and science festivals. Adv Physiol Educ 35: 275–279, 2011. doi:10.1152/advan.00026.2011. Link | ISI | Google Scholar6. Rodenbaugh DW, Collins HL, Chen CY, DiCarlo SE. Construction of a model demonstrating cardiovascular principles. Am J Physiol 277: S67–S83, 1999. PubMed | ISI | Google Scholar7. Russ RD. A simple model to demonstrate the isovolumic contraction and rapid ejection phases of the cardiac cycle. Am J Physiol 275: S246, 1998. doi:10.1152/advances.1998.275.6.S246. Link | Google Scholar8. Swain DP. The water-tower analogy of the cardiovascular system. Adv Physiol Educ 24: 43–50, 2000. doi:10.1152/advances.2000.24.1.43. Link | ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: V. Oommen, Dept. of Physiology, Christian Medical College, Bagayam Campus, Vellore, Tamil Nadu 632002, India (e-mail: [email protected]ac.in). Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Collections More from this issue > Volume 42Issue 2June 2018Pages 256-259 Copyright & PermissionsCopyright © 2018 the American Physiological Societyhttps://doi.org/10.1152/advan.00004.2018PubMed29616565History Received 3 January 2018 Accepted 16 February 2018 Published online 4 April 2018 Published in print 1 June 2018 Metrics

theory lectures are boring and sleep inducing for students, and it is difficult to get their full attention during 1 h of lecture ([7][1]). The ability of students to concentrate diminishes 20–25 min after the start of the lecture ([5][2]). There is also a lack of active participation of students

There are many resources available for Physiologists to help improve the quality of their teaching. This review is a collection of simple and innovative models as well as other teaching resources that can be applied in the Indian setting. Articles from 1989 to 2012 from the journal Advances in Physiology Education were reviewed. A set of five criteria was applied to identify if the idea presented could be replicated easily and at an affordable cost in the Indian setting. The selected articles were reviewed and presented system wise. This collection of resources will serve as an index to help Physiologists locate and implement easily affordable and practical tools to supplement their teaching.

IlluminationsRespiratory belt transducer constructed using a singing greeting card beeperAnand Bhaskar, Selvam Subramani, and Rajdeep OjhaAnand BhaskarDepartment of Physiology, Christian Medical College, Vellore, Tamilnadu, India; and , Selvam SubramaniDepartment of Physiology, Christian Medical College, Vellore, Tamilnadu, India; and , and Rajdeep OjhaDepartment of Bioengineering, Christian Medical College, Vellore, Tamilnadu, IndiaPublished Online:01 Mar 2013https://doi.org/10.1152/advan.00166.2012MoreSectionsSupplemental MaterialPDF (335 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat an article by Belušič and Zupančič (1) described the construction of a finger pulse sensor using a singing greeting card beeper. We felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers, such as Pneumotrace (http://www.adinstruments.com/products/mlt1132; marketed by AD Instruments), also use such piezoelectric material. After modification, the beeper was attached to the chest using Velcro straps. The strain induced on the piezoelectric material of the beeper by the chest movement produces a corresponding voltage change, which can be recorded by a computer using data-acquisition systems or observed using an oscilloscope. The construction of the respiratory belt transducer is described below.1Materials needed.The following materials are needed for the construction of the respiratory belt transducer (Fig. 1):Beeper of a singing greeting card or buzzer (2.5 cm in diameter)Velcro strap (60 cm long and 2.5 cm wide)Latex strip (25–30 cm long and 2 cm wide)Copper wire (1–2 mm thick)Fast curing epoxy compoundFig. 1.Parts of the respiratory belt transducer. A: piezoelectric beeper (front view). B: piezoelectric beeper (back view). C: respiratory belt transducer (side view). D: respiratory belt transducer (front view). E: respiratory belt transducer (back view).Download figureDownload PowerPointConstruction of the respiratory belt transducer.The copper wire was bent and cut to make two brackets of 2 cm length each. They were soldered to both sides of the metal surface of the beeper (Fig. 1A). A small quantity of resin base and hardener of a fast curing epoxy compound (M-Seal, Pidilite Industries) was thoroughly mixed and fixed at the center of the metal surface of the beeper (Fig. 1B). The protrusion thus formed (knob) transfers horizontal chest movement into a vertical strain over the piezoelectric material. Once the mixed epoxy compound had set, the latex strip was inserted through the brackets such that it passed over the knob made of epoxy (Fig. 1C). The ends of the latex strip were then stapled to the Velcro strap (Fig. 1, C–E). The wires from the beeper were connected to the input of a custom-built data-acquisition system (CMCdaq) to record respiratory movements. A video of the construction of the respiratory belt transducer can be seen here: http://www.youtube.com/watch?v=brTVT--qcwI&feature=youtube.Recording of respiratory movements.Normal respiratory movements were recorded by strapping the respiratory belt transducer to the chest at the level of the nipple. The transducer also responded very well to rapid respiratory movements (Fig. 2). A demonstration of respiratory sinus arrhythmia was done for undergraduate medical students during a theory lecture using this transducer along with the finger pulse sensor described in the article by Belušič and Zupančič (1). Construction of this transducer was also given as a practical assignment to Master of Technology Clinical Engineering students, and they were able to construct it quite easily.Fig. 2.Respiratory movements recorded using a computerized data-acquisition system (CMCdaq). The waveform on the left was recorded during normal breathing, and the waveform on the right shows the response to rapid deep breathing.Download figureDownload PowerPointThis transducer can be used to monitor the depth and rate of respiration. It can also be used to record respiratory movements in animals. The respiratory belt transducer is versatile enough to be connected to other data-acquisition systems, such as BIOPAC or PowerLab, to record respiratory movements for teaching or research purposes. This respiratory belt transducer can be easily constructed, and it is inexpensive (costs ∼ $2) compared with other commercially available respiratory belt transducers.DISCLOSURESNo conflicts of interest, financial or otherwise, are declared by the author(s).AUTHOR CONTRIBUTIONSAuthor contributions: A.B. and R.O. conception and design of research; A.B. and S.S. performed experiments; A.B. and R.O. analyzed data; A.B. and R.O. interpreted results of experiments; A.B., S.S., and R.O. prepared figures; A.B. drafted manuscript; A.B. and R.O. edited and revised manuscript; A.B., S.S., and R.O. approved final version of manuscript.FOOTNOTES1A video demonstrating the construction of the respiratory belt transducer is available as Supplemental Material at the Advance in Physiology Education website.ACKNOWLEDGMENTSThe authors thank Dr. Suresh Devasahayam (Department of Bioengineering) for suggestions for modifying the piezoelectric beeper. The authors also thank Dr. Aneesh Joseph and L. Natarajan (Department of Physiology, Christian Medical College) for help in recording the video.REFERENCE1. Belušič G, Zupančič G. Singing greeting card beeper as a finger pulse sensor. Adv Physiol Educ 34: 90–92, 2010.Link | ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: A. Bhaskar, Dept. of Physiology, Christian Medical College, Vellore 632 002, Tamilnadu, India (e-mail: [email protected]com).Supplemental datavideoS1.wmv (8.66 MB) Download PDF Previous Back to Top Next FiguresReferencesRelatedInformationCited ByDesigning a Visualization Model to Represent Emotional Changes Through Low-Cost Physiological Sensors with Genre Perspective11 May 2022Color Spectrographic Analysis of Respiratory Sounds: A Promising Technology for Respiratory MonitoringThe Open Anesthesiology Journal, Vol. 14, No. 1Monitoring of Obstructive Sleep Apnea Using Virtual Instrumentation Techniques17 May 2019A sensor based low cost drowning detection system for human life safetyA review of the polygraph: history, methodology and current status8 July 2015 | Crime Psychology Review, Vol. 1, No. 1 More from this issue > Volume 37Issue 1March 2013Pages 117-118Supplemental Information Copyright & PermissionsCopyright © 2013 The American Physiological Societyhttps://doi.org/10.1152/advan.00166.2012PubMed23471261History Received 10 December 2012 Accepted 10 December 2012 Published online 1 March 2013 Published in print 1 March 2013 Metrics

IlluminationsA simple electronic stethoscope for recording and playback of heart soundsAnand BhaskarAnand BhaskarDepartment of Physiology, Christian Medical College, Vellore, Tamil Nadu, IndiaPublished Online:01 Dec 2012https://doi.org/10.1152/advan.00073.2012MoreSectionsSupplemental MaterialPDF (859 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations undergraduate teaching of cardiovascular physiology often involves lectures on heart sounds. To complement these lectures, online resources are commonly used. The audio files of heart sounds are available as free downloads on the internet from websites of stethoscope manufacturers such as Thinklabs (http://www.thinklabsmedical.com/sound-library.html) and Littmann (http://solutions.3mindia.co.in/wps/portal/3M/en_IN/Littmann/stethoscope/education/heart-lung-sounds/). The auscultation assistant website of the University of California-Los Angeles (http://www.wilkes.med.ucla.edu/inex.htm) is also an excellent resource for abnormal heart and lung sounds. Heart sounds can also be demonstrated during practical sessions (1). It is, however, interesting for students to see the recording and playback of heart sounds during lecture. Described below is a simple electronic stethoscope that can be used for performing such recordings. It is a modified version of the stethoscope microphone described in a YouTube video available at http://www.youtube.com/watch?v=iqjxOapIKbE. This electronic stethoscope will be useful for departments that do not have phonocardiographs, electronic stethoscopes, echocardiography, or ready internet access.MATERIALS AND METHODSMaterials required.The following materials are required to create the electronic stethoscope (Fig. 1):Fig. 1.A: stethoscope chest piece. B: medical grade tube. C: condenser microphone of the computer microphone. D: condenser microphone. E: stereo plug.Download figureDownload PowerPoint1. An ordinary stethoscope.2. Medical grade tubing.3. A condenser microphone with a 3.5-mm stereo plug.4. A laptop (Microsoft XP/Mac OS or later) with Thinklabs phonocardiography software.Construction.Remove the stem of the stethoscope chest piece (Microtone, India) from the tubing. Attach a medical grade tube of 5 cm length and 6-mm inner diameter to the stem of the chest piece. Insert a condenser microphone on the other end of the tube. This end may have to be heated to facilitate the proper fixing of the microphone. The microphone is then connected to a 3.5-mm stereo plug. Computer microphones already connected to a stereo plug can also be used. The electronic stethoscope is now ready for use.Recording of sounds.The diaphragm of the electronic stethoscope is placed over the mitral area, and the stereo plug of the electronic stethoscope is connected to the microphone input of a laptop installed with Thinklabs phonocardiography software. Sounds are recorded using this software. The software can be freely downloaded from the Thinklabs electronic stethoscope website (http://www.thinklabsmedical.com/software-download.html).It is safer to use a laptop disconnected from the main power supply (floating) and running on battery. More details about the safety precautions can be accessed here: http://www.thinklabsmedical.com/safety/. During recording, the sound waves can be seen on the waveform track of the software (Fig. 2). The microphone input volume may be adjusted to clearly visualize the waveform.Fig. 2.Heart sounds [first heart sound (S1)] recorded using the electronic stethoscope and Thinklabs phonocardiography software.Download figureDownload PowerPointAfter being recorded, the sounds can be played back. Recorded sounds are better heard with headphones. Sounds can be amplified after the selection of an area of interest. Additional functions, such as filtering of the heart sounds, display of the frequency spectrum of the heart sounds, and changing the tempo of the recorded sounds, can also be performed. The software also provides an option to label the heart sounds (Fig. 2). The recorded sounds can be saved in the software format for easy access or can be exported to .wav or .mp3 sound formats. The following link provides more details regarding the use of the phonocardiography software: http://www.thinklabsmedical.com/support-and-manuals/26-electronic-stethoscope/support/74-stethoscope-software-user-manual.html.This electronic stethoscope can also be used for recording Korotkoff sounds (Fig. 3). For this, the diaphragm of the stethoscope is kept over the brachial artery while the blood pressure cuff is inflated and deflated.Fig. 3.Korotkoff sounds recorded using the electronic stethoscope and Thinklabs phonocardiography software.Download figureDownload PowerPointThe making of the electronic stethoscope and the recording of heart sounds and Korotkoff sounds can be seen as a YouTube video at the following link: http://youtu.be/T5UytMyPeSM.RESULTSUse of the electronic stethoscope.Recording and playback of heart sounds with the above electronic stethoscope was demonstrated to 60 undergraduate medical students during a lecture on heart sounds. The recording of Korotkoff sounds and heart sounds was also demonstrated in a laboratory session for students undergoing the M.Tech clinical engineering course.1 In both cases, the students were keenly interested in the recordings.The making of this stethoscope was also given as an assignment to M. Tech clinical engineering students, who were able to construct this quite easily.DISCUSSIONThis electronic stethoscope is simple to construct. It is versatile in that it can be used to record heart sounds and Korotkoff sounds as well as other sounds such as lung sounds and sounds from the joints. This electronic stethoscope is useful for familiarizing the students with the nature of Korotkoff sounds before practical sessions on the recording of blood pressure.DISCLOSURESNo conflicts of interest, financial or otherwise, are declared by the author(s).AUTHOR CONTRIBUTIONSAuthor contributions: A.B. conception and design of research; A.B. performed experiments; A.B. analyzed data; A.B. interpreted results of experiments; A.B. prepared figures; A.B. drafted manuscript; A.B. edited and revised manuscript; A.B. approved final version of manuscript.FOOTNOTES1The heart sounds and Korotkoff sounds recorded with this electronic stethoscope are available as Supplemental Material at the Advances in Physiological Education website.ACKNOWLEDGMENTSThe author thanks Dr. Vinay Timothy Oommen (Department of Physiology, Christian Medical College) for reviewing and editing the manuscript. The author also thanks Dr. V. Kamalakannan and Dr. Aneesh Joseph (Department of Physiology, Christian Medical College) for the help in recording the videos.REFERENCES1. Brunner M, Moeslinger T, Spieckermann PG. Echocardiography for teaching cardiac physiology in practical student courses. Adv Physiol Educ 25: 36–43, 2001.Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: A. Bhaskar, Dept. of Physiology, Christian Medical College, Vellore 632 002, Tamil Nadu, India (e-mail: [email protected]com).Supplemental dataaudioS1.mp3 (980.38 kb)audioS2.mp3 (205.68 kb) Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Cited ByA low-cost solution for converting existing stethoscope into tele-stethoscope in resource-constrained setting for COVID-19 pandemicJournal of Family Medicine and Primary Care, Vol. 9, No. 11Real-World Evaluation of the Eko Electronic Teleauscultation System31 August 2018 | Pediatric Cardiology, Vol. 40, No. 1Stetho-phone: Low-cost digital stethoscope for remote personalized healthcareDigital phonocardiographic experiments and signal processing in multidisciplinary fields of university education14 August 2017 | European Journal of Physics, Vol. 38, No. 5Development of an Electronic Stethoscope15 December 2015 More from this issue > Volume 36Issue 4December 2012Pages 360-362Supplemental Information Copyright & PermissionsCopyright © 2012 the American Physiological Societyhttps://doi.org/10.1152/advan.00073.2012PubMed23209021History Received 16 May 2012 Accepted 10 September 2012 Published online 1 December 2012 Published in print 1 December 2012 Metrics