Medical Physiology Commons^™

Thermal Physiological Ecology Of The Relict Leopard Frog At Hot And Cold Springs, Robert P. Pelletier Iii

UNLV Theses, Dissertations, Professional Papers, and Capstones

The relict leopard frog (Rana onca) once ranged across drainages in southern Nevada, northwestern Arizona, and southwestern Utah. Following a decline, the species only persisted in a few geothermally influenced hot springs, which led to the perspective that hot springs were high-quality habitat. Rana onca has been under intensive, multiagency management and the species has been translocated to establish additional populations, including at cold-water sites. Three research studies are presented into the thermal physiological ecology of R. onca with the aim of informing conservation strategy. The research was focused at a thermally influenced hot spring and a cold-water spring to …

An Analysis Of The Influence Of Human Disease Pathogens On Core Behaviors Of The Black-Legged Tick, Emily F. Marinko

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ixodes scapularis, the black-legged or deer tick, is a vector for several different disease-causing microbes, including the causative agent of Lyme disease. As such, it is a major health concern for people living within its range in the eastern half of the United States, a habitation area that is increasing due to climate change. Despite its medical relevance as a disease vector, there is still much to learn about the basic behavior of these arachnids in the wild. Thus, the major hypothesis of this thesis is that ticks that are infected with specific human disease-causing microbes behave differently than those …

Effects Of Body Armor On Respiratory Muscle Fatigue And Muscle Blood Flow During Progressive Treadmill Marching, Kathryn Bell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: Torso-borne loads such as body armor are essential for modern military operations but impose mechanical and metabolic strain. These physiological stressors can trigger the inspiratory metaboreflex, which redirects blood flow from locomotor to respiratory muscles, further reducing muscle oxygen and endurance. While aerobic fitness has been shown to alleviate these effects, the interaction between sex, aerobic capacity, and oxygenation under load is not well understood. This study examined the physiological effects of torso-borne load carriage on respiratory muscle fatigue, skeletal muscle oxygenation, and exercise performance to volitional exhaustion and the degree to which sex and aerobic capacity influence these …

Core Temperature While Swimming In Warm Open Water With And Without A Wetsuit, Katsiaryna Afanasyeva

UNLV Theses, Dissertations, Professional Papers, and Capstones

Triathlon is a popular sport which attract participants from all over the world. In general, triathlon is a safe sport with risk of death being about 1.74 deaths per 100,000 participants (Harris et al., 2017). The swimming portion of the race can be dangerous, posing particular risks due to open water conditions and the physical demands of the event. This study investigated the effects of wetsuit use on core temperature in warm open-water swimming (27.9–28.3°C). Four experienced triathletes (2 males, 2 females; age 49.50 ± 7.83 years) completed two 700-meter open-water swims at a submaximal pace—once wearing their personal full-sleeve …

Investigating The Influence Of Environmental Stressors To Exopolysaccharide Production In Soil Cyanobacteria: Genomic And Physiological Perspectives, Benjy Sedano-Herrera

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cyanobacteria are photosynthetic microbes with essential roles in Earth’s ecosystems. The secretion of long–chain polysaccharides, known as exopolysaccharides (EPS), is a key trait facilitating cyanobacterial adaptation to diverse ecosystems. Genomics studies have shown that aquatic cyanobacteria harbor multiple gene copies encoding EPS export proteins, likely conferring a selective advantage in lakes or oceans. In addition, physiological experiments showed that nutrient limitation in aquatic habitats influences EPS production, affecting cyanobacterial fitness. However, whether terrestrial cyanobacteria also harbor multiple EPS-related genes and how nutrient limitation impacts their EPS production is not well understood.In the first chapter of my thesis, we investigated the …

Physiology And Genomics At The Bottom Of The World: Genome To Phenome, Amy Christine Klink

UNLV Theses, Dissertations, Professional Papers, and Capstones

Mammals are exposed to a suite of physiological challenges based on the environment in which they inhabit. Animal individuals can overcome challenges associated with the dynamic nature of their habitat through variation in phenotypic traits. The plasticity of a phenotype relies on an individual’s genome and the transcription factors that act on regulatory elements. Species living in Antarctica display physiological specializations to withstand harsh conditions, such as severe cold temperatures, shifts in available ice habitat, and annual fluctuations in daylight. To explore the connections between an individual’s genome and its phenotype, we investigated two physiologies of the Antarctic Weddell seal …

Seasonal Climate And Environmental Conditions Associated With Physiological Variations Of Southwestern United States Pines, Taylor Brewer

UNLV Theses, Dissertations, Professional Papers, and Capstones

Juvenile and adult conifers in the southwestern United States are vulnerable to a range of different abiotic and biotic factors, yet it is unclear how their stress tolerance varies across environments. Predicted increases in the frequency and intensity of disturbance as well as greater climate and weather variability across the region highlight the potential for differential physiological responses across tree species and populations. This thesis focuses on two physiologic mechanisms, hydraulic vulnerability and mortality, that could be altered by climate change in two broadly distributed southwestern United States conifers: ponderosa pine and pinyon pine.

In chapter 2, I measured the …

Physiological And Biomechanical Response To Indoor Cycling With And Without The Ability To Sway, Alina P. Swafford

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: Bicycles have been around since the early 19th century. Since the invention of the bicycle, it has taken on several purposes. People have used bicycles as a means of transportation, leisure, exercise, and sport. The number of individuals who participate in a cycling event per year has increased. With the increase in popularity, research related to cycling has also increased. Research related to the physiology and biomechanics of cycling are of particular areas of interest. Balance is a crucial component of understanding why we cycle a certain way. Some research has labeled balancing on a bicycle as cycling sway. …

Survey Of How Irregularities In The Electrical System Of The Human Heart Link To Different Heart Arrhythmias, Jazmine Boloor

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis explores the circuital pathway that a signal takes within the heart throughout a full heartbeat and provides a timing analysis. It then surveys the different pathways that could arise in the electrical system of the heart, and the associated heart diseases linked to the location of each pathway. Common heart arrhythmias such as atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, atrial flutter, and atrial fibrillation are surveyed, and their pathways are analyzed. Electrocardiograms are presented to aid in understanding of the timing analysis associated with irregularity in heart function. Finally, this thesis explores an avenue of the heartbeat …

Oxygen Consumption In Highly Skilled Baseball Pitchers, Jesse Clingman

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to describe the physiological demands of highly skilled baseball pitchers during pitching, along with pitch metrics. Three junior college and three professional (n = 6) baseball pitchers participated in this study. Participants completed a graded exercise test (GXT) to volitional exhaustion to determine maximal oxygen consumption (VO2 max) and estimated body fat percentage, height, and body mass were measured on day one of testing. Next, participants faced live batters on a baseball field while wearing a portable metabolic analyzer (Cosmed K5) to measure respiratory gases including oxygen consumption (VO2) and carbon dioxide produced (VCO2) …

Diurnal Regulation Of Exercise-Induced Myocardial Signaling And Transcription, Charli Aguilar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: Exercise is well known for its many benefits on the body and most notably the heart. Recent emphasis, and significant resources, have been dedicated to elucidating the molecular mechanisms through which exercise exerts its pluripotent beneficial effects on health and the prevention of disease. A continuous evolution in this field has sought to modulate and optimize exercise in various ways to maximize the benefits. In recent years, a growing appreciation for the impact of circadian rhythms has gained traction and their influence on many essential biological functions have been integrated into exercise physiology (i.e. - chrono-exercise), as well as …

Sight Deprivation And Metabolic Effects During The Ymca Bench Press Test, Kyle Cruz

UNLV Theses, Dissertations, Professional Papers, and Capstones

Several studies have investigated the effect of sensory deprivation, particularly sight. However, very few have demonstrated the impact of sight deprivation while exercising to cadence blindfolded. This study aimed to determine exercise performance during a common muscular endurance evaluation, the YMCA Bench Press Test (YBPT), while blindfolded compared to a sighted condition. Twenty-five healthy participants (11 male, 14 female, 168 ± 7.7cm, 68 ± 11.7kg, 23 ± 7.5% fat mass) were recruited from the University of Nevada, Las Vegas student populations and communities. After a YBPT familiarization session, participants completed testing in a counterbalanced order, following the same procedures. A …

The Role Of Nutrition And Hormone Signaling In Extended Larval Development And Obesity In Starvation-Selected Drosophila Melanogaster, Jennifer M. Clark

UNLV Theses, Dissertations, Professional Papers, and Capstones

Brief periods of starvation are a common stressor that most animals encounter in the wild and must be able to survive in order to maximize their fitness. Starvation resistance of the adult fruit fly, Drosophila melanogaster, is thought to be primarily conferred by adult fat stores, body size, metabolic rate, behavior, and activity levels. Additionally, flies selected for starvation resistance also often show delayed pupariation, which is usually indicative of altered hormone signaling. How starvation selection extends development and if it contributes to adult starvation resistance remains incompletely studied. Identifying the targets of starvation selection that cause extended development and …

Utilizing Breathing Techniques To Maximize Training Performance, Peyton Cater

UNLV Theses, Dissertations, Professional Papers, and Capstones

Anaerobic exercise causes metabolic acidosis to occur in the muscle, which is unfavorable for sustaining high intensity activity, as fatigue starts to set in. In order to compensate for the onset of fatigue produced by an acidic environment, respiratory alkalosis, induced by hyperventilation, can be performed to mitigate these effects. In contrast, research has shown that slowing down the breath rate, such as a two second inhale and three second exhale, has led to an increase in performance outcomes. Purpose: To investigate power output and the physiological responses after implementation of different breathing techniques during the recovery periods of intermittent …

Rapid Evolution Of Starvation Resistance In Drosophila: Physiological And Molecular Mechanisms, Austin Joseph Mckenna

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Gibbs lab has maintained starvation-selected Drosophila melanogaster for >130 generations. These starvation-selected flies evolved an obese phenotype with a suite of physiological differences compared to control-fed flies. Previous studies have shown that long-term starvation-selected Drosophila contain more lipids, have lower metabolic rates and develop more slowly than controls. This dissertation encompasses 1) Examining the molecular mechanisms contributing to starvation resistance, 2) Functional validation of the candidate plin1 allele, and 3) Rapid physiological and genomic evolution in starvation-selected Drosophila.

Starvation-selected Drosophila survive starvation conditions much longer than control-fed flies. This study took a simple approach to identify possible differences in …

Trade-Offs Between Survival And Reproduction In Starvation-Selected Drosophila Melanogaster, Tammara Beeghly

UNLV Theses, Dissertations, Professional Papers, and Capstones

Evolutionary outcomes are demonstrated by traits that affect an organism’s schedule of reproduction and survival. These life history traits are reflected in an organism’s physiology, development and behavior. Environmental changes, such as availability of nutritional resources, can profoundly affect evolutionary outcomes of individuals and populations. When shortages arise, there will be trade-offs in the allocation of resources, where one trait prevails at the expense of another.

In the laboratory, we can mimic conditions in nature and study the specific effects of the conditions that we re-create. In our case, over 100 generations of Drosophila melanogaster have been selected for starvation …

Effect Of Exercise And Hypoxia On Plasma Telomerase, Charli D. Aguilar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: Telomerase reverse transcriptase (TERT) is the enzyme that adds telomeric sequences to the end of linear chromosomes. Exercise has shown to upregulate acutely leukocyte TERT after just 30 minutes of running on a treadmill at 80% of VO2max (Denham et al., 2016). Hypoxia inducible factor 1 (HIF-1) is also a mediator of TERT in in vitro (Nishi et al., 2004). Moderate acute exposure to hypoxia was associated with substantial increases in plasma TERT in a recent study on rats (Wang et al., 2014). The specific aim of the current study was to identify if acute hypoxia upregulates plasma TERT …

Worked To Leisure: The Intersections Of Volunteerism, Work, And Leisure, Denise Nicole Cook

UNLV Theses, Dissertations, Professional Papers, and Capstones

Volunteerism and work are topics which academics in several disciplines research. This study is an examination of the intersection of work and volunteerism via the lens of role theory. According to role theorists, the term role refers to behaviors which are either a result of social position or expectations (Biddle 1986). Cognitive role theorists use vocabulary such as “role conflict” and “role overload” to identify incongruences sometimes found in roles individuals have in their lives (Biddle 1986). These incongruences are primarily examined as they relate to individual level consequences. This research explores volunteerism and work as they relate to role …

Dietary Intake And Energy Expenditure Of Pararescuemen During Routine Training, Andrea Woita

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pararescuemen are one group of Air Force Special Operations Forces (SOF) who engage in vigorous physical training to achieve mission readiness. This type of training requires high energy expenditures and matching dietary intake to support basic physiological needs and to meet performance demands. However, few studies have investigated the energy expenditure and dietary intake of SOF and none have specifically examined these behaviors in Pararescuemen. The goal of this investigation was to determine the energy expenditure and dietary intake of Pararescuemen during routine training - a period when these operators receive supervision and guidance for performance improvements, recovery, and career …

Thermal And Developmental Ecology Of Pupfish, Cyprinodon, Alexander Jones

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pupfish from the genus Cyprinodon are among the most endangered groups of fishes on the planet, with nearly 40% of species being threatened with extinction. These pupfishes are often assumed to be the most temperature tolerant of all fish, coping with temperatures as low as 0 °C and as high as 44 °C. However, conflicting data exist and certain measures of thermal tolerance are not markedly higher in pupfish compared to common game fish. Pupfish egg production and growth has been known to be hampered at temperatures well below what they apparently experience in nature. I addressed why eggs fail …

Factors Influencing Induction Of Desiccation Tolerance In Bryophytes: Redefining Fundamental Aspects Of The Organism’S Relationship With The Environment In Xeric Habitats, Joshua Lee Greenwood

UNLV Theses, Dissertations, Professional Papers, and Capstones

If one wishes to understand the ecological role, range, habitat preferences, selective pressures, reproduction, response to climate change, and the potential for survival under climactic change, range expansion and range contraction for species and populations of bryophytes, an understanding of their survival of the desiccated state, is essential. In order to further our understanding of desiccation tolerance in mosses, three projects were undertaken. The first of these investigated the nature of desiccation tolerance in mosses, specifically if desiccation tolerance can be induced; thereby providing a desiccation tolerant phenotype in a moss species generally considered desiccation sensitive (Physcomitrella patens, the model …

Oral Vs. Nasal Breathing During Submaximal Aerobic Exercise, Chase Ovila Platt Lacomb

UNLV Theses, Dissertations, Professional Papers, and Capstones

When comparing oral breathing versus nasal breathing more volume of air can be transported through the oral passageway, but nasal breathing can lead to slower respiration rates and cleaner inspired air. The purpose of this study is to find the most efficient mode of breathing during different intensities of submaximal aerobic exercise. There were 9 males and 10 females that completed this study. First test was a VO₂ Max test, 3.0 mph for 3 minutes, with increases in 1.0 mph every minute after that. Using a regression equation running speeds were determined for each individual’s submaximal intensities. The desire …

The Grass Shrimp, Palaemonetes, Pugio: Hypoxic Influences On Embryonic Development, Christensen C. Javier

UNLV Theses, Dissertations, Professional Papers, and Capstones

Grass shrimp,Palaemonetes pugio, can survive in brackish waters and estuarine ecosystems despite the frequent oscillations and fluctuations in salinity, temperature and oxygen. AdultP. pugiohave the ability to osmoregulate (Romney and Reiber 2011), change cardiac parameters to tolerate temperatures (not yet published, Mika and Reiber) and oxyregulate (Guadagnoli and Reiber 2013). Manipulation of cardiac parameters allows for these methods of regulation. However, cardiac contraction and internal convection of oxygen do not occur until later stages of embryonic development. Studies focused on these morphological and physiological advantages may provide further understanding of the regulatory mechanisms within grass shrimp embryos, larvae and adults. …

Life History Tradeoffs And The Costs Of Reproduction In Arizona Bark Scorpions (Centruroides Sculpturatus), Michael Marie Webber

UNLV Theses, Dissertations, Professional Papers, and Capstones

Tradeoffs in life history evolution result from conflicts in the time and energy that can be simultaneously invested in activities such as growth, reproduction, and survival. Reproduction is an energetically costly activity for organisms, and is known to elicit alterations in the daily activity patterns of individuals. I investigated reproductive tradeoffs in the Arizona Bark Scorpion,Centruroides sculpturatus. To better understand the nature of tradeoffs in this species, I examined the influence of reproductive state on the predatory efficiency and thermal preference of reproductive females. Further, I examined the influence of reproductive activities (i.e. gestation) on the ability of reproductive females …

Effect Of Racing Flats On Running Economy In Male Adolescent Runners, Paul Hafen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to investigate whether running economy differs in racing flats versus standard running shoes in high school cross-country runners. In order to measure running economy the oxygen cost of running (mL O₂∙kg^-1∙min^-1) was measured in 20 male adolescent runners (mean age = 16.25 ± 0.97 years, 5 km best time = 17.52 ± 0.78 min) when running two separate trials at a controlled speed. The speed was determined by estimating treadmill running speed at 85% of each runner's VO_2max. Each trial required the participants to run while …

Oxidative Stress For An Acute Bout Of Bikram Yoga In Healthy, Trained Adults, Kimberly Anne Trocio

UNLV Theses, Dissertations, Professional Papers, and Capstones

BACKGROUND:Generation of free radicals resulting in oxidative damage has been linked to cellular damage, aging, and human disease. Many studies have reported that physical exercise can contribute to oxidative stress. Further, exercise in a hyperthermic environment can promote additional oxidative stress. It is important to consider that practices in yoga may be beneficial in reducing oxidative stress according to some studies. The compound effects of exercise and hyperthermic exposure are experienced in the practice of Bikram yoga, the original "hot" yoga. Because Bikram yoga and other hot exercise classes are an increasingly growing fitness trend, it is necessary to investigate …

Investigation Of Magnetic Resonance Imaging And Spectroscopy For The Detection Of Breast Cancer, Robert Thomas Etnire

UNLV Theses, Dissertations, Professional Papers, and Capstones

Magnetic resonance imaging (MRI) of the breast offers an alternative to screening mammography which may benefit those women at high risk for breast cancer, women under the age of 40, and those with dense breast tissue. One concern with MRI is the number of high false positives. Coupling MRI with magnetic resonance spectroscopy(MRS) may lower the number of false positives, and thus improve the diagnostic capabilities of MRI for the clinician. MRS for breast imaging focuses on the total choline containing compounds in the spectra in the suspected breast lesion to analyze areas of concern. The results of the study …