bluuebunny/crossref_metadata_2025 huggingface dataset:
Basic integrative disciplines in a Dentistry course: 10 years evaluation of the experience of Piracicaba Dental School of the University of Campinas, Brazil
Authors: Marcondes Fernanda Klein
Published: November 2023

Teaching physiology subjects in an integrated way may improve students motivation and learning. Considering this, since 2004, the basic courses of Anatomy, Histology, Biochemistry, Physiology and Pharmacology are taught in two integrative disciplines: Bioscience I and II, in the first and second semester of Dentistry course. The aim of this work is to describe this teaching experience and to present the perception of students during this 10‐years‐period of integration. At the end of each semester, all the disciplines were evaluated by the students. The students' evaluation between 2003 (one year before integration) and 2014 (10 years after integration) were compared. In Biosciences I and II, the professors give lectures, practical classes, team works, educational games, portfolio, writing works, and integrative activities. During integrative activities, the students receive questions to be answered in groups for oral discussion and dramatizations in the following class. For these activities, the professors present the themes which are previously discussed in order to integrate Anatomy, Histology, Biochemistry, Physiology and Pharmacology concepts. To assess students' learning and to be considered approved, the final grade includes theoretical tests, team and individual activities and the performance in the integrative activities. In addition, as teaching‐learning methodology, there is also a discussion of the theoretical exams with all students and professors in class. After the integration of Anatomy, Histology, Biochemistry, Physiology and Pharmacology disciplines, the students' perception about basic disciplines has been improved. Before the integration, the students did not consider Anatomy, Histology, Biochemistry, Physiology and Pharmacology as necessary to the curriculum of a Dentist. Between 2004 and 2014 the students' have significantly changed their opinion and have recognized those disciplines as necessary to their academic instruction. Considering the assessment of learning, before the integration, 35 to 60% of students considered that the assessment criteria were clear and fair. After the integration, this percentage had raised to 96 to 100%. In the evaluation of disciplines, the students were requested to point out their positive and negative aspects. In 2003, the positive aspect considered was only the dedication of professors. In 2014, the students mentioned that Biosciences I and II provided them the basic fundamentals to understand the body functioning which is very important to the Dentist. In addition, they evaluated that the integrative activities helped them to understand the relations between the morphology and the physiology of the organs and body systems. These data indicate that the integration of the basic disciplines may improve the process of teaching and learning.
Vertical Integration of Basic Science and Clinical Medicine During Case Based Learning Sessions for Third Year Medical Students
Authors: ElSayed Suzan Kamel , Niculescu Iuliana
Published: November 2023

Vertical integration of basic sciences with clinical teaching has emerged as an important issue in medical education. We describe a teaching method in which a case‐based learning session was used to implement vertical integration of basic physiology and pathophysiology with an internal medicine clinical case. Third year medical students were introduced to an internal medicine case by a clinical faculty member. In the first part of the session the clinician identified the key questions that students would need to address in order to understand the pathophysiology and to develop a differential diagnosis. Next, students engaged in self‐directed learning to answer the previously identified questions. Students were able to work either individually or in pairs or as a group. In the next part of the session a biomedical scientist presented the relevant underlying science that provided a context for the case. Finally, the scientist and the clinician worked together to show how the basic and clinical content were integrated and to engage the students in the teaching process. An evaluation survey revealed that the students held positive attitudes toward such integrated instruction.
What Are You Blubbering About? A Study of Comparative Cold Physiology
Authors: Clarke Megan M , Craighead Daniel H , Alba Billie K , Shank Sean W
Published: November 2023

During PhUn Week 2016, we attended State College Area High School to introduce the students to some principles of cold physiology. The purpose of the activity was to compare the different adaptations in various species during acute cold water submersion and the accompanying cardiovascular responses. In humans, there is a reduction in skin blood flow when skin temperature drops. Animals more adapted to cold environments, such as penguins and whales, have additional adaptations to maintain thermoregulation in their natural habitat. Penguins have a dense layer of feathers, whereas whales have a thick layer of blubber, to protect them from the cold. In the classroom, students were able to mimic these phenotypes by using bubble wrap as feathers and vegetable shortening as blubber. Before submerging their hands into the cold water, students were asked to hypothesize which condition: bare hand, “feathers”, or “blubber” would be best in the acute cold water exposure. One student per group was the subject and the other group members took the roles of timer and measuring heart rate and blood pressure. Baseline measurements of heart rate and blood pressure were taken. Then, the designated subject placed their bare hand into the ice water and the timer began the stopwatch to determine the submersion time. The subject removed their hand when they could no longer endure the cold water or when the timer reached two minutes. Tolerance time was recorded. Immediately post‐submersion, heart rate and blood pressure were measured and the subject rated their perceived coldness on a scale of one to ten. This protocol was repeated for the imitation of feathers and blubber trials. Students then determined which adaptation was most effective in the cold environment and reasoned the cardiovascular responses to each scenario. With this activity, students were able to utilize comparative physiology to understand the different insulative properties of varying morphological features.
Annual PhUN Week Service Learning Events improve student content mastery and civic engagement
Authors: Rhinehart Erin M
Published: November 2023

Service‐Learning (SL) integrates meaningful community service with instruction and reflection to enrich the learning experience, teach civic responsibility, and strengthen communities. In language, arts and social science courses, it enhances learning and facilitates classroom inclusivity, providing opportunities to apply learned content to real‐world situations with guided reflection. While Physiology and Biology courses use SL less frequently, it is likely to enhance learning outcomes in these courses as well, while providing resources for K‐12 science education and public science literacy. Therefore, we tested the hypothesis that SL in introductory biological/physiological sciences courses would enhance student engagement, civic responsibility and course content mastery. To test this hypothesis, we conducted and assessed annual K‐2 educational outreach events in connection with the American Physiological Society program PhUN (Physiology Understanding) week over a period of 3 years. The SL project assignment required students to use backward design strategies to create stand‐alone learning module lesson plans with learning goals aligned with K‐2 state and federal standards of science education. The annual 3 hour, Friday night events were open to the public and structured as “reverse science fairs”. Over the three years, more than 200 children and their families were participated in hands‐on learning activities designed to teach a variety of concepts such as the connection between exercise and metabolism, sensation and perception and brain structure and function. Pre‐ and post‐service reflections and surveys show that SL, in this context, facilitates students' confidence in content mastery and enhances student engagement, especially in 1st year and 1st generation undergraduates. The experience especially enhanced “commitment to civic engagement” in male students, and had the greatest impact on the “confidence to talk to the public about science” for female students. The SL attitude pre‐ and post‐assessments also revealed that underrepresented minority students in the sciences (URM) had greater gains than non‐URM students in commitment to “future SL activities” and the notion that it is essential for “universities to perform community service”. In addition, the multi‐year project produced a book of state‐standard‐aligned K‐2 lessons for the local elementary school and much needed support for local public science literacy. Therefore, SL, as a pedagogy in introductory biological/physiological sciences courses, functions as a student‐centered, high‐impact practice, giving students new views on the applications of classroom course content and enhancing civic responsibility, while also inspiring the next generation of physiologists.

Support or Funding Information

NSF CAREER IOS‐1350448 and APS PhUN week
A Comparison of High Fidelity Patient Simulations and Computerized Clinical Cases on Undergraduate Student Learning of Physiology
Authors: Harris David M , Li Wei
Published: November 2023

High fidelity patient simulations (HFPS) have been shown to improve learning of science knowledge and skills in nursing and medical students. A few studies have shown improved learning in undergraduate students. Because HFPS are expensive and resource intensive, it is important to determine whether the increase in learning is worth the high cost. The purpose of this study was to determine if computerized clinical cases (CC), a low cost alternative, could produce similar learning as HFPS.

Methods

Thirty‐two undergraduate biomedical students were randomly assigned to two groups. Group A participated in a HFPS about asthma and then a CC on hemorrhage. Group B participated in a CC on asthma and then a HFPS on hemorrhage. The HFPS and CC were identical cases. A pretest with 10 questions was given before their activities and a post‐test was given after their activities. Students also took a survey regarding their confidence levels after the simulation activities. The 10 questions consisted of 4 related to asthma, 4 to hemorrhage and 2 unrelated to the cases as controls.

Results

Both groups achieved higher scores on the posttest for the asthma questions with no difference between groups. There was no significant increase in scores on either the hemorrhage or control questions. There was a significant increase in 2 of the 7 statements about confidence. One involved confidence in understanding pathophysiology of a patient and the other was the relevance of physiology to medicine.

Discussion

These data suggest that CC and HFPS are similar in short term learning for some material. Future studies are needed to determine if there are other benefits of HFPS in undergraduate students and whether these justify the cost of this pedagogy in undergraduate students.
Does Size Really Matter? A Comparison of Class Size and Student Outcomes in Introductory Physiology Courses
Authors: Kroeker Carol Anne Gibbons
Published: November 2023

Traditionally, it's been thought that small class size resulted in better student outcomes. As teaching styles change and inquiry‐based learning becomes more common, this may not necessarily be the case.

This study examined student outcomes for introductory physiology courses of different sizes at two different institutions over a three year period. One course averaged 30 students per year while the other course averaged 200 students per year. Both courses were taught by the same instructor, using the same teaching materials, lecture style, and inquiry‐based techniques. The same hands‐on lab exercises were taught and the same lab report questions were assigned. Tutorials involved teaching the same case studies (by the instructor at the small institution and by teaching assistants under the direction of the instructor at the larger institution). Each course used the same exam questions and consisted of multiple choice and short answer formats. With class size being the only significant variable, it was possible to test if class size was a key factor in student success.

Students in both courses (and in all years) were given a pre‐test to assess the student knowledge base at the beginning of the course. In all cases, the pre‐test showed similar levels of starting knowledge between the different‐sized courses (31.1±1.8% for the smaller course vs. 30.6±0.9% for the larger course). Student outcomes were compared between the classes by assessing exam grades (overall scores as well as individual question scores), comparing lab report grades, and by comparing final course grades. Assessment of all these parameters showed no significant difference between the two courses and this result was seen in each year of the study. Lab report grades, averaged over 5 lab reports, differed by less than 2% between the large and small courses (not a significant difference). Mean exam scores and final grade scores were also not significantly different for any of the years of the study. Course grades between the courses differed by less than 3±0.8%.

These results would indicate that class size alone was not a significant factor in determining student outcomes. Students showed similar success in both large and small classes when all other factors were similar. Interactive lectures, as well as the use of case studies and other inquiry‐based learning methods may have a much greater influence on student learning and success than class size.
Physiology Labs at the Cutting Edge: Multidisciplinary Design of Systems and Devices for Physiology Measurements
Authors: Rozner Robert H , Batts Jacob T , Nossa Gianna K , Pullins Calvin , Pelaez Nancy
Published: November 2023

Physiology as a discipline is uniquely positioned to engage undergraduate students in transformational research, which often involves multidisciplinary projects. However, physiology lab instruction is often centered around historical and not current physiology research methods. When students perform a protocol without realizing the relevant cross‐cultural and social impact from those methods, they miss the opportunity to discover whose interests are being served and the importance of physiology. In this study, a lab course arena was provided where students could solve real‐world physiology problems. Each module gave basic information, a problem, and protocols. Students were challenged to design a solution and then to experimentally test it. They optimized storage of blood, built a device to measure rat respiration, tracked stages of the rat estrus cycle and designed equipment to identify parameters that alter compliance of myometrium, and invented a rat heart bypass device. As a result, students used what they learned in other disciplines: biology, chemistry, physics, and calculus. They practiced interdisciplinary communication with teamwork to develop something unique with minimal constraints. Importantly, a common misconception was identified: students replicated experiments to get better at the experiment, and not to account for and measure variability, as taught in statistics. When people looked at various solutions, examined how well each worked, and decided how to explain the cross‐cultural and social value, their thought processes simulated performance in a real‐life work environment much better than traditional physiology lab courses. Clearly, physiology will still be poised to advance society if students are asked to solve real‐world problems.

Support or Funding Information

A portion of this research is supported by the National Science Foundation under grant #1346567 for Advancing Competencies in Experimentation ‐ Biology (ACE‐Bio).
Challenges With Initial Implementation of an Intelligent Formative Assessment System
Authors: Wilson Eric , Kibble Jonathan D , Bellew Christine , Hernandez Caridad , Castiglioni Analia , Khan Asra , Kamin Carol , Riordan Anne , Dauner Shila , Lorens Dale , Gangopadhyaya Ananya , Rajagopal Nimmi , Gaglani Shiv , Haynes Ryan , Lineberry Matthew
Published: November 2023

With a grant from the National Board of Medical Examiners' Stemmler Fund, the University of Illinois at Chicago (UIC) and University of Central Florida (UCF) have introduced an intelligent formative assessment system (www.Osmosis.org) into the preclinical phase of their MD curricula. This web‐browser based and mobile application presents students with individualized regimens of study questions that aim to leverage the testing effect, spaced repetition and the mixed‐practice effect to aid long term retention. In the first semester of use, 90 of 120 UCF students tried to use the system answering an average of 136 items per individual though subsequent use of the system has continually decreased. We performed two initial focus groups with first year medical students to learn about the strengths and weaknesses of the IFAS and what factors have affected students' decisions about what study aids to adopt. Groups of 4–5 students gave informed consent and the discussions were audio taped for transcription and thematic analysis. A preliminary coding of the audio files suggests that student decisions about what study aids to use in medical school are strongly affected by advice from upperclassmen in the early part of the first year. Near‐peer advice appears to have high face validity and is readily accepted. The data also suggested that concerns for lack of time and demand for efficiency weigh most heavily on student decisions about what tools to use. The data suggest that high quality orientation is needed when introducing new technology, with widespread consultation in the learning community, including faculty and upperclassmen. New applications must be highly intuitive and easy to use for successful adoption.

Support or Funding Information

National Board of Medical Examiners' Stemmler Fund
Expanding on case studies: combined active learning techniques in small undergraduate physiology classrooms
Authors: Caldari Cristina
Published: November 2023

In response to the common challenge of testing student's critical thinking, many professors turn to case studies, a powerful pedagogical technique that utilizes active learning in order to engage students and that can easily be adapted to fit the instructor's needs. Instructors can employ case studies to encourage students to apply the information learned in class to real‐life, or at least possible scenarios. The objective of this study was to test the effectiveness of a combination of clicker questions and peer instruction in case study‐based learning in a small physiology classroom. Students from two different iterations (2014, n=19; 2016, n=10) of an upper‐level Nutritional Physiology course were separated into groups of three or four. Students were presented with a case study regarding a patient demonstrating symptoms of digestive system dysfunction and were asked to use clickers for anonymous and individual selection of answers to multiple choice questions about the scenario presented (individual selection). After individual selection was completed the histogram with the class results was shown. If there was < 80% consensus for the correct answer students had to discuss their answers as a group (peer‐group‐instruction), and re‐vote as a group. If < 80% consensus was still observed, each group took turns discussing their answer with the rest of the classroom (peer‐class‐instruction), and the class re‐voted. Each case study had 5–6 questions, and three case studies were utilized throughout the semester. Correct student answers before and after peer instruction were quantified, and a survey was performed at the end of the semester to measure student satisfaction. On average 55.1%, 83.8%, and 96.4% of students picked the correct answer after individual selection, peer‐group‐instruction, and peer‐class‐instruction, respectively. There were no significant differences in the results of individual selection, peer‐group‐instruction, and peer‐class‐instruction between the 2014 and 2016 cohorts. Additionally, the questions were categorized as testing “knowledge”, “comprehension”, and “analysis” under Bloom's taxonomy. Questions in the lower levels of Bloom's taxonomy (“knowledge” and “comprehension”) were more likely to be answered correctly after peer‐group‐instruction while questions in the upper levels of Bloom's taxonomy (“analysis”) were more likely to be answered correctly after peer‐class‐instruction. Students rated the exercise an average of 4.75 on a 1–5 scale asking how much they enjoyed the exercise. These results suggest that peer‐instruction and clicker questions in case study‐based learning is a fun, valuable technique for improving student knowledge, comprehension, and analysis, and that it can yield positive results regardless of the student cohort.
The use of a case study from pop culture improves student test scores and evaluations in a cardiovascular physiology class
Authors: Berg Ronan
Published: November 2023

Background

According to Zehr's ‘middle ground hypothesis’, the use of case studies from pop culture provides students with a basis for discovery learning by providing familiar and comfortable mental landscape where various scientific principles can be explored (Zehr, 2014). In the present study, I sought to examine the effects of this approach on student learning of cardiovascular physiology.

Method

During a 5‐week course on cardiovascular physiology for 2nd‐year medical students, I used a scene from Terminator 2: Judgement Day (1991), where the fictional character Miles Dyson suffers multiple fatal gunshot wounds, to teach the cardiovascular effects of severe hemorrhage in two classes (intervention group; n = 50), while a conventional patient case study on severe hemorrhage was used to teach the same physiological principles in a third class (control group; n = 28). At the end of the term, the students filled out an evaluation form, and then underwent a 10‐minute multiple choice test on the related core curriculum in cardiovascular physiology.

Results

The test scores were significantly higher in the intervention than in the control group (Figure 1). The two groups rated their own skills in physiology similarly (NS), while the intervention group rated the quality of the teaching in physiology higher than the control group (p < 0.05). The majority of the students in the intervention group acknowledged that the use elements from pop culture made the teaching more fun, and enhanced both their understanding of the physiological principles taught, while also motivating them to participate more during class; however, less than half of the students found that the approach led to more self‐study (Figure 2).

Conclusion

Although the use of a narrative from the Terminator franchise did not improve student's perception of their own skills in physiology, they rated this teaching approach higher than conventional teaching, and it did improve their test scores in the relevant core curriculum at the end of term. In accordance with Zehr's ‘middle ground’ hypothesis, my findings thus suggest that the use of case studies from pop culture in the physiology classroom improves student learning.

Support or Funding Information

None
Clinical Scenario Videos Improve D.M.D Students' Perception of the Basic Sciences and Ability to Apply Content Knowledge
Authors: Metz Cynthia Jayne , Metz Michael James
Published: November 2023

Students enrolled in D.M.D. programs often have difficulty understanding the importance of basic science classes, such as physiology, for their future careers as practicing dentists. In order to help alleviate this issue, a series of video modules were created using simulated patients and custom‐designed animations that showcase medical emergencies in the dental practice. Students formatively assessed their knowledge using embedded questions. These responses indicated that while students could initially recognize the cause of the medical emergency, they had difficulty in applying their knowledge of physiology to the scenario. In two of the three videos, students drastically improved their ability to answer high‐level clinical questions at the conclusion of the video. Additionally, when compared to the previous year of the course, there was a significant improvement in unit exam scores on clinically‐related questions (6.2% increase), while no change was found for the basic science questions. Surveys were administered to freshmen and senior dental students to compare their perception of these changes. Freshmen students indicated a more positive perception of the physiology course and its importance for success on board examinations and their dental career. The most positive reported aspects of the clinical scenario modules were the clear applications of physiology to real‐life dental situations, the interactive nature of the videos, and the improved student comprehension of course concepts. These results suggest that online modules may successfully be used to improve student perceptions of the basic sciences, and enhance the ability of students to apply basic science content to clinically‐important scenarios.
The Comparison of Student Performance Between Flipped Classroom and Traditional Teaching Approach
Authors: Gopalan Chaya , Klann Megan C
Published: November 2023

Flipped teaching has gained educators' attention in the recent years due to the nature of its classroom design where students are expected to complete class preparation prior to student‐ centered activities in the classroom. We compared scores on the first three major exams between a fully‐flipped classroom and five years of traditional unflipped teaching in an undergraduate sophomore level physiology course. The number of students per year ranged from 77 to 191. With the exception of student performance from one year of unflipped teaching (2013), all other years' (2010–2014) performances were significantly lower (p<0.001 or lower) compared to that of the flipped teaching. This study suggests that flipped teaching improves student performance compared to that of lecture‐based traditional teaching practice.
Musculoskeletal morphology of the hip and thigh of the black‐footed ferret (Mustela nigripes) Virginia L. Naples, Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois 60115
Authors: Naples Virginia L
Published: November 2023

The pelvic girdle, hindlimb skeleton and hip and thigh musculature of Mustela nigripes, the black‐footed ferret, are described and compared to those of the closely related mustelids, Mustela putorius, the European ferret, Mustela eversmanni, the Siberian ferret, the mustelid outgroup, Neovison vison, the mink, and the distantly related Felis catus. The M. nigripes hindlimb musculoskeletal system reflects the typical mammalian bauplan, although proportions among mustelids and with F. catus differ. Relative sizes and differences in orientations of lines of action in thigh muscles from those of the compared species improve the ability of M. nigripes to run swiftly with flexed knees through small diameter (mostly) Cynomys burrows, and to attack prey underground. While attacking, a ferret grasps the prey, biting the anteroventral side of the neck, and must maintain the grip for long enough to ensure that strangulation occurs. Most kills occur inside cramped tunnels dug by prairie dogs, sized for their body proportions. Skeletal adaptations for this lifestyle in M. nigripes include greater sacroiliac joint range of motion, an enlarged iliac blade, and blocky femoral condylar attachment sites for relatively enlarged gluteal and hamstring muscles. Additionally, reoriented gluteals maximize mediolateral trunk stability; there is no tibial caudofemoralis attachment, and the semitendinosus and biceps femoris join the tendo calcaneus. The latter is reinforced posteriorly by a long, slender tenuissimus. Some adaptations also contribute to bipedality. An upright stance allows ferrets increased height while observing their surroundings, and would be advantageous for seeking predators or prey. Reorientation of pelvic and thigh muscles, which result from more distal insertions into an aponeurosis that includes an expanded quadriceps tendon that also covers the patellar region farther distally. These muscles also insert into the calcaneal tendon, which improves the mechanical advantage of these muscles, increasing the stability of the hindlimb while the ferret is standing bipedally.
Comparing Femur Cross‐sectional Morphology in Young Outbred Mice Following Daily Exposure to Muscle‐, Impact‐, or Combined Loading of the Hind Limb Skeleton
Authors: Smolinsky Amanda N , Middleton Kevin M
Published: November 2023

Limb bones are exposed to a multitude of intrinsic and extrinsic loading forces which they must resist in order to prevent fracture and maintain function. Bone is a plastic tissue which can adapt to encountered loads by increasing cortical thickness in areas of high strain and resorbing cortex in areas of low strain, thereby optimizing strength, weight, and metabolic requirements. While exercises such as running and jumping are known to induce changes in the cross‐sectional dimensions of limb bones, the relative contributions of muscular contractions and extrinsic ground reaction forces (GRF) in altering bone morphology are not fully understood. We compared femur gross and cross‐sectional morphology in mice exposed to four loading environments that differ in the source of forces imposed on the skeleton: swimming (muscle‐dominated), impact loading via falling (GRF‐dominated), running (combined muscle and GRF characteristic of natural locomotion), and sedentary controls. Four‐week‐old male Hsd:ICR mice were randomly assigned to treatment groups and completed loading exercises daily for 20 days. Mice were injected twice with fluorochrome labels during the final week of treatment to allow measurement of mineral apposition rates and regionalization. Undecalcified femoral mid‐diaphyseal sections were photographed using light and fluorescent microscopy and analyzed for cross‐sectional properties and mineral apposition patterns. We found that the falling impact group had the greatest distal femoral width, but the swim group had the greatest width at the mid‐diaphysis. The jump impact group demonstrated significantly greater cross‐sectional area and moments of inertia than controls, indicating increased resistance to torsion and bending compared to other loading regimes. Examination of mineral apposition patterns showed that mineral apposition was greatest posterolaterally in all groups, with additional medial or posterior cortical drift characterizing each loading treatment. These results indicate regional sensitivity of the growth and morphology of the femur to muscle‐ and GRF‐derived loads and suggest that impact loading induces the growth of stronger bones than other forms of exercise. Future analyses will use 3D geometric morphometrics to examine overall shape differences in femur, tibia, and pelvis following loading treatment.

Support or Funding Information

University of Missouri School of Medicine
Low‐impact climbing exercise during growth enhances skeletal muscle function
Authors: Organ Jason , Biro Kelly , Vickery Benjamin , Monnin Gregory , Waning David
Published: November 2023

High‐impact exercise (running/jumping) improves musculoskeletal mechanical properties such as bone strength and muscle maximum contractile force, but is also associated with higher incidence of skeletal fracture. Thus, it is not an appropriate treatment for patients with an elevated risk of fracture, such as osteogenesis imperfecta (brittle bone disease). Mechanical loads originating from multiple, off‐axis directions, however, have elicited anabolic skeletal responses even when magnitudes are relatively low. This represents a potential alternative to high‐impact exercise for improving musculoskeletal mechanical properties. The effects on muscle function, however, are not well characterized. To examine the potential effects on skeletal muscle, we raised female C57BL/6 mice to 4 months of age in custom enclosures that prevent (parking deck) or require (fine‐wire) manual and pedal grasping while balancing above narrow wire substrates, and compared them to mice raised in standard mouse cages (shoebox). At sacrifice, we measured soleus and extensor digitorum longus weight, specific forces, and half relaxation times across a range of physiological stimulation frequencies in an ex vivo whole muscle contractility assay. Muscle weights and relaxation times were not significantly different between experimental groups. Specific forces of the soleus muscles were significantly higher in the fine‐wire group than either of the other groups, especially at middle to high stimulation frequencies. Extensor digitorum properties were not different among groups. This suggests that muscle function was enhanced by low‐impact exercise, although the response was inconsistent between muscles dominated by faster myosin heavy chain isoforms (extensor digitorum longus) and slower myosin heavy chain isoforms (soleus).

Support or Funding Information

Showalter Research Trust, IUPUI Biomechanics and Biomaterials Research Center
Anatomical descriptions of developing hypoglossal motor neurons in the green frog, Lithobates clamitans, and bullfrog, Lithobates catesbeiana, through metamorphosis
Authors: Anderson Curt W , Carroll Andrew J
Published: November 2023

During metamorphosis anuran amphibians undergo dramatic changes in the central nervous system to facilitate the transition from an aquatic to a semi‐terrestrial lifestyle. Dramatic remodeling of organs as well as the development of new structures takes place in a very short period of time. For example, these tadpoles undergo the process of metamorphosis where they transform from a herbivore dependent on a feeding apparatus consisting of scraping mouth parts that efficiently harvest algae for dietary consumption to a carnivorous diet where the animal actively captures prey with a protrusible tongue and jaw musculature. Prior to metamorphosis, tadpole larvae do not have a developed tongue. During metamorphosis the structures of the tongue are not developed, for instance the anlage of the tongue does not appear until stage 10 and is not fully developed until stage 24. Muscular contraction of the adult tongue in Ranid frogs is primarily directed by hypoglossal nuclei in adult models. Although the circuitry and descriptions of the hypoglossal complex has been described in adult models, the dramatic development during metamorphosis of these neurons has been not studied completely. Retrograde labeling and proliferation of cell development studies of hypoglossal motor nuclei in the brainstem of developing Lithobates catesbeiana and Lithobates clamitans larvae have revealed morphological changes including peripheral nerve disconnection from the brainstem in T/K stages XV‐adult. Additional morphological differences including size and distribution between larvae and adults are substantial. A nearly 1/3 increase in average cell number and a corresponding 2/3 loss in average cell area (μm2) was observed. Significant alterations in the differentiation, morphology and distribution of the motor neurons were also observed. Cellular proliferation was characterized in the ventral horn of the brainstem with mitotic activity from stage XV‐until metamorphic climax. There is a distinct period of time during development where peripheral connections from the spinal cord are lost and the cells undergo significant restructuring.

Support or Funding Information

Idaho INBRE NIH Grant #P20 RR0116454
Potus Flavus: Linking Tail Integumentary Function and Microanatomical Structure
Authors: Ruiz Palacios Saul A. , Plochocki Jeffrey H. , Rodriguez‐Sosa Jose R. , Hall Margaret I.
Published: November 2023

Animal anatomy is an important area of study in relationship to function and structural differences across species. Unlike human anatomy this is an area which is heavily understudied and presents many questions still unanswered. The Kinkajou or Potos flavus is a rainforest mammal that is native to regions of Central and South America. As the only member of the Potus genus and with nocturnal habits, little is known about the microanatomy of the kinkajou. In this study we utilize basic tissue staining techniques and light microscopy to evaluate and quantify the microanatomy of the kinkajou's prehensile tail as it relates to functionality. Our experimental design utilized tissue sections from a young adult at the cranial, middle and caudal regions of the tail with dorsal and ventral sections of the trunk acting as control groups. Using a routine Hematoxylin and Eosin stain we measured the tissue for thickness in the epidermis and dermis, dermal ridge number and size as well as hair follicle numbers. Our results indicate negative correlations between epidermis thickness and dermal ridges, dermal ridge number and diameter as well as hair follicle to dermal ridge height. In conclusion, the ventral side of the kinkajou tail displayed a thinner epidermis with a highly concentrated dermal ridge count while the dorsal side of the tail was follicle dense with few dermal ridges. These findings support the functionality of the prehensile tail through increased sensitivity and tactile acuity for a necessarily increased grip on the ventral side of the tail.

Support or Funding Information

Support provided by Midwestern University.
Copulatory Fit of Common Bottlenose Dolphin (Tursiops truncatus) Genitalia
Authors: Orbach Dara , Brennan Patricia
Published: November 2023

Sexual selection is the primary force that drives gross morphological variation of male genitalia in many species. Less information is known about how male and female genitalia fit together during copulation or how sexual selection and mechanical constraints during copulation interact and shape reproductive organs. Marine mammals offer important insights into evolutionary forces that act on genital morphology in both sexes because of adaptations to extreme environmental constraints (e.g., hydrodynamic drag forces acting on the penis during copulation while swimming, the necessity to prevent seawater from entering the uterus, and the challenge of successful intromission while moving in a 3‐D space). Cetaceans (whales, dolphins, and porpoises) have a fibroelastic penis type and their vaginas have muscular folds, both characteristics that are rare among mammals and unique to cetartiodactlys. We used excised male and female reproductive tracts from deceased adult common bottlenose dolphins (Tursiops truncatus) to assess how deep the penis penetrates the vagina, which anatomical landmarks of male genitalia contact morphological features of females, and how genital shape influences copulatory interactions. Frozen‐thawed vaginas remained flaccid and were stained with iodine, while penises were mechanically inflated and formalin‐fixed to maintain rigidity. Female and male reproductive tracts were ct‐scanned independently. The penis was then inflated inside the vagina in a position that approximates real intromission and the reproductive tracts were ct‐scanned together. Resulting images were reconstructed in transverse and sagittal planes. In conjunction with video observations of copulations by free‐swimming dolphins, our results suggest that the tip of the bottlenose dolphin penis navigates around the female's single vaginal fold to achieve successful insemination. Understanding the coevolution of male and female reproductive anatomy under extreme environmental constraints has broad applications to conservation and captive breeding programs. Copulatory fit can provide clues of how genitals interact to influence fertility and improve artificial insemination techniques.
Variation of Facial Musculature between Wolves and Domestic Dogs: Evolutionary Divergence in Facial Movement
Authors: Burrows Anne , Diogo Rui , Waller Bridget , Kaminski Juliane
Published: November 2023

Evolution of the domestic dog (Canis familiaris) is intimately associated with the evolution of human social behavior and domestic dogs themselves evolved from wolves. Social behavior of both domestic dogs and wolves includes facial displays as a means of communication. These displays have been described and reveal several differences between dogs and wolves. In an effort to better understand the mechanistic events in the evolution of domestic dogs and the potential morphological correlates of their facial displays, the objective of the present study was to compare gross and micro‐anatomy of facial musculature between domestic dogs and wolves. Dissections of cadaveric heads were carried out using standard dissection tools (domestic dog N=6; gray wolf N=4; red wolf N=1) and the presence/absence of facial muscles was documented along with attachments and variation in these characters. Select muscles were sampled for histochemistry and immunohistochemistry. Gross results revealed that the dog and wolf samples were similar to one another in all facial musculature except for the levator anguli occuli medialis and the retractor anguli occuli lateralis muscles. All dog specimens routinely had these muscles while the wolf specimens varied in their presence and size. Microanatomical results revealed that dogs had more robust facial vibrissae in the zygomatic region than the wolf specimens, along with more robust intrinsic vibrissa musculature. The connective tissue layer between the epidermis and facial musculature was thicker in dogs than wolves, suggesting formation of an incipient SMAS (superficial musculoaponeurotic system), a connective tissue layer found in some primates that may be associated with facial mobility. Lastly, both dog and wolf facial musculature were dominated by fast‐twitch myosin fibers but dogs had a greater percentage of slow‐twitch myosin fiber reactivity than the wolf sample, suggesting that dogs may be able to sustain facial muscle contraction longer than wolves. These results partially reflect those from previous studies on dog and wolf facial movement. The larger area of connective tissue between the epidermis and facial musculature may be associated with the greater facial mobility in dogs relative to wolves, as shown by DogFACS and WolfFACS studies.
Free‐body Diagram Force Analysis in 2D and 3D: A Tool to Study Comparative Vertebrate Biomechanics
Authors: Osborn Michelle L , Rau A.R.P. , Ge Jinghua , Homberger Dominique G.
Published: November 2023

Free‐body diagram force analysis is a tried and true method that has been used by physicists and engineers to analyze the forces and torques that act on a physical body. Although this method was adapted to the analysis of skeleto‐muscular systems of vertebrates more than a half century ago, it has rarely been used in analyses of real organisms by functional anatomists, who often rely on intuitive assessments of forces and movements of skeleto‐muscular systems. The reluctance to adopt this more rigorous method of analyzing forces may be based on the fact that the principles of the free‐body diagram force analysis need to be applied to and constructed for each system individually. Our study demonstrates how this analytical method estimates the musculo‐fascial forces of a coherent, complex skeleto‐muscular system based on the known weights of body parts and the measurable geometry of the system, using the human shoulder suspension apparatus as a model. We evaluated the advantages and limitations of the usual application of the free‐body diagram force analysis in 2D and developed an extension of this method into 3D based on reconstructed and visualized x‐ray CT data. Although more complex, the 3D extension of this analysis is more generally applicable and requires fewer a priori assumptions. It also allows for an analysis of the forces acting on a skeletal element with paired joints, such as the skull, as well as for the determination of the center of gravity in 3D models. In addition, this analytical method of static conditions is less involved than methods that analyze dynamic conditions. Taken together, the free‐body diagram force analysis has broad applicability to the comparative biomechanics of vertebrates, as well as to clinical and evolutionary studies, by creating mechanical models whose predictions can be tested via experimental means.
Adult female human bony pelvis obstetric morphology differences with respect to age are not due to selection
Authors: Auerbach Benjamin M.
Published: November 2023

Recent studies call into question whether human pelvic morphology reflects evolutionary tradeoffs suggested in the obstetrical dilemma, in which responses to competing selection pressures for obstetrical sufficiency and locomotor efficiency shape the pelvis. Nevertheless, dimensions of the true pelvis likely evolved in response to selection pressures for parturition of large fetuses. Thus, females with narrow bony birth canals may have encountered difficulties in childbirth in the past, even though recent research shows that fetal size and maternal size covary, lessening the possible selection pressure that might result from mismatches in fetal and maternal size. Moreover, the dimensions of the birth canal do not scale isometrically among humans, so groups with smaller body size have proportionally larger dimensions in the true pelvis than groups with larger body sizes.

In studies of skeletal remains from multiple archaeological sites, age‐at‐death in females is correlated with dimensions of the true pelvis, with younger females exhibiting narrower dimensions, a pattern not observed in males. These studies proposed selective pressures as leading to this discrepancy, though continued growth of the pelvis in adulthood could also be a cause for the pattern. Here, I examine whether selection motivated the relationship between female age‐at‐death and true pelvis dimensions.

Fourteen linear pelvic dimensions were measured from the skeletons of 327 adults (188 females, 139 males) associated with six late Holocene Native American archaeological sites. Individuals were aged into two categories: “young” (approximately 25 years old and younger), and “not young” (approximately older than 25 years). Measurements were mean‐scaled within sex‐and‐ age groups. If selection were acting against young females with narrow dimensions, the variance for younger females should be greater than within not young females. Comparisons show no differences in variance between age groups. Thus, there is no evidence to support selection as driving the differences in pelvic dimensions between age groups. Further analyses, based on studies of integration and age‐group comparisons, indicates that the pelvis continues to grow throughout early adulthood. This growth is not driven by any single region of the pelvis, but rather appears to be the result of continued remodeling of the entire true pelvis. These results caution against making assumptions about the roles of evolutionary forces in shaping morphological variation.

Support or Funding Information

Funding provided by the National Science Foundation, BCS Division Collaborative Research Grant #0962752.