Category Archives: Physiology

Airway, breathing and circulation (the ABCs) have been stalwart concepts since the inception of EMS training. These concepts are obviously important, and it is difficult, if not impossible to understand how these systems truly function without addressing what is happening at the cellular level of physiology.

In certain aspects, possessing a foundational understanding of the cellular physiology behind the ABCs is more relevant than the ABCs themselves. Human physiology can be a difficult concept to grasp. Due to the complexity and academic nature of physiology, many EMS providers may believe it is easier to avoid or skim over this concept. This article will introduce readers to cellular action potentials in anything but an academic manner.

You may be asking yourself, why is it important for EMS providers to understand the concept of cellular action potentials? One of the answers to this question is quite simple. If our bodies are unable to achieve a cellular action potential, we would cease to exist as a living human being. Every time our heart beats, we take a breath or have a conscious thought, it is the result of a cellular action potential. In a nutshell, any normal or abnormal physiologic action revolves around achieving or hindering a cellular action potential.

Before getting into the practical aspects of physiology, we need to take a short academic side trip. Cations are positively charged ions, anions are negatively charged ions. Depolarization is moving the extracellular cation sodium into the intracellular space. Think of depolarization as the activation of any body function. When systems within our body achieve depolarization, our heart beats, we take a breath or have a conscious thought, and so on.

Cells within our bodies are unable to maintain constant and sustained levels of depolarization. This is because cells have limited amounts of stored energy. Constant depolarization will result in a depletion of stored energy, and the cell will eventually lack resources to function. This is where repolarization comes into to play.

Repolarization is moving the intracellular cation potassium out to the extracellular space. Think of repolarization as the deactivation of any bodily function. This allows the cell time to replenish energy stores so it can be depolarized again.

To simplify this concept, we will look at the schoolhouse theory. Think of cells as schoolhouses rather than biological structures. These schools control all the functions that normally occur within our bodies. As an example, there are schools that control heart function, breathing, cognition and so forth. The teachers and administrators of the school recognize the importance of classrooms inside the schoolhouse. This is because inside the school is where most of the action and learning typically occurs.

Within our community, we have three types of students who regularly attend the schools. First and foremost, is sodium. Think of sodium (cation = positively charged ion) as an optimist within the student population. The positivity associated with sodium has the potential to create action wherever its located. When sodium comes to school, it prefers to spend the entire day outside of the building.

There is also potassium. Think of potassium (cation = positively charged ion) as the pessimist within the student population. Even though potassium is a positively charged ion, it tends to see the world from a glass-half-empty perspective. When potassium comes to school, it prefers to spend the entire day inside of the building.

Lastly there is calcium. Think of calcium as incoming freshman. Calcium feels awkward but wants to fit into the student body; it sees hanging out with sodium as a means to readily fit in. As a side note, sodium hates to open doors for itself. Since this is the case, sodium reluctantly allows calcium to tag along so long as calcium facilitates opening any door for sodium.

Under this illustration, sodium starts the day outside the schoolhouse, potassium starts inside the schoolhouse, and calcium hangs out wherever sodium is located. There is no activation of body function because sodium is outside of the school rather than inside. This is referred to as the resting cellular potential. Cells within our bodies expend a large amount of energy to achieve this state of resting potential.

As sodium stays outside and potassium stays inside, their parents are concerned the students will become one dimensional. To avoid this tendency, they hire a school bus driver. This school bus driver comes in the form of an electrical impulse. His job starts when there is more sodium outside the school in comparison to potassium inside the school. This school bus driver has only two responsibilities:

Think of the school bus driver as an employee who has a bad attitude with poor work ethics. He consistently approaches these two jobs with minimal enthusiasm and effort.

When there is more extracellular sodium in comparison to intracellular potassium, the school bus driver is instructed to come to the school. As a reminder, he arrives in the form of an electrical impulse. It is this electrical impulse that tells sodium the facilitator of action to move into the schoolhouse. As agreed upon, calcium rushes up front to open the door and sodium moves into the schoolhouse. When the extracellular sodium moves into the schoolhouse, depolarization occurs. Depolarization results in whatever physiologic process the school controls. The heart will beat, breathing occurs, there is conscious thought, etc.

When most of the sodium has moved into the cell, the school bus driver tells potassium to move out of the school. When the intracellular potassium moves out of the schoolhouse, repolarization occurs. Repolarization results in deactivating whatever physiologic process the school controls.

As a side note, calcium gets stuck at the door during this process. This is like opening the door for your party at a busy restaurant. After your party goes through the door, there are people on the inside wanting to come out. Calcium, being a conscientious door holder, will wait until the intracellular potassium comes out of the schoolhouse before joining sodium. After potassium is told to move out of the schoolhouse, the school bus driver has completed his two duties and leaves the school yard.

After the school bus driver leaves, intracellular sodium realizes it stinks to be inside the schoolhouse. On the other hand, extracellular potassium realizes it stinks to be outside the schoolhouse. With their mutual perspectives, sodium moves back outside, potassium moves back inside, and calcium follows sodium wherever it goes. This is referred to as the return to resting potential. Once the cell attains resting potential, the school bus driver is instructed to come back and initiate the process of depolarization and repolarization, with the resulting return to resting potential. This process continues indefinitely until we die.

Why is the concept of cellular action potentials important to EMS providers? Understanding cellular action potentials will help EMS providers understand what is causing their patients to present with specific clinical findings. As an example, lets look at what causes a patient to present with an increased heart rate. This might be caused by increased levels of sodium moving into their cardiac cells. A bradycardia might be the result of too little sodium moving into those same cardiac cells.

Cellular action potentials also apply to the administration of medications. Medications that increase sodium influx will typically increase associated physiology. Medications that inhibit sodium influx will typically decrease associated physiology. Some medications can inhibit calcium from opening doors for sodium. This typically results in decreased physiology, as less sodium moves into the cell because calcium isnt there to hold the door open.

Cellular action potentials have a direct effect on normal patient physiology as well as patients suffering from injury or disease. Medications prescribed to patients or medications which are administered by EMS providers obviously influence cellular action potentials. Understanding cellular action potentials will help EMS providers relate to what is occurring within their patients.

For those interested in learning more about the concept of cellular action potentials, watch the video below. To test your knowledge, take the quiz: Quiz: Depolarization and polarization cellular action potential.

Physiology

/Filmcast Ep. 552 – The Gentlemen – /FILM

January 30, 2020 medical

David corrects a gross mistake he made about the physiology of the Navi. The cast feels nostalgic withStar Trek: Picard. For the feature review, David, Devindra, and Jeff takes onThe Gentlemen, the latest film by director Guy Ritchie.

Read about the life of a Hollywood Boulevards Supermanhere. Read about howThe Gentlemenis a safe space for menhere.

Thanks to our sponsor this week: Quip

Feature (~49:00)The GentlemenSpoilers(~01:09:00)

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/Filmcast Ep. 552 - The Gentlemen - /FILM

Physiology

Newly minted professors of distinction to be celebrated – CU Boulder Today

January 30, 2020 medical

Four members of the University of Colorado Boulder facultyhave been named 2019Professors of Distinction by the College of Arts and Sciences in recognition of their exceptional service, teaching and research.

The new professors of distinction areNoel Clarkof physics,Stephen Graham Jonesof English,Robert Pasnauof philosophy, andKenneth P. Wright Jr.of integrative physiology.

This reveredtitleis reserved for scholars and artists of national and international acclaim whose college peers also recognize as exceptionally talented teachers and colleagues. Honorees of this award hold this title for the remainder of their careers in the College of Arts and Sciences at CU Boulder.

The four will be honored onMonday, Feb. 3,at 3:30 p.m. in the CASE Auditorium/Chancellors Hall. At the free and public event, Clark, Jones and Wright will give a public presentation based on his research or scholarly work. Pasnau is unable to attend the event this year but will give his presentation next year.

Wright, Pasnau, Clark, and Jones. (left to right).

Noel Clark, whose talk is titledSplashing Around in Soft Matter,received his PhD in Physics from MIT in 1970. He subsequently held the positions of research fellow and assistant professor of applied physics at Harvard, before moving to CU Boulder in 1977.

Research in Clark's group is directed toward understanding and using the properties of condensed phases, ranging from experiments on the fundamental physics of phase transitions, such as melting, to the development of liquid crystal electro-optic light valves.

His primary experimental tools are laser light scattering, electrooptics, video microscopy and high resolution synchrotron X-ray scattering. Much of the research is on the physics of liquid crystals, phases of matter having structure intermediate to that of liquids and solids, and on the physics of colloids, suspensions of one material in another that exhibit order on large length scales.

Stephen Graham Jones, whose Feb. 3 talk is titledBeing Indian is Not a Superpower,is the Ivena Baldwin Professor of English. He received his PhD in Creative Writing (Fiction) from Florida State University in 1998, and came to CU in 2008. At that time, he had five novels and one story collection published.

Since then he's published 11 more novels, five more story collections, and some novellas and comic books and chap books, and he's currently got north of 300 stories published. He has been an NEA recipient, has won the Texas Institute of Letters Award for Fiction, the Independent Publishers Award for Multicultural Fiction, a Bram Stoker Award, four This is Horror Awards, and hes been a finalist for the Shirley Jackson Award, the World Fantasy Award, the Wonderland Book Award, and the Colorado Book Award.

Hes also made Bloody Disgustings Top Ten Horror Novels, and will soon receive the Western Literature Association's Distinguished Achievement Award. At CU Boulder he's won the Carolyn Woodward Pope Prize for Faculty Publication, the Boulder Faculty Assembly Excellence in Research Award, and the Kayden Book Award, and he's a faculty affiliate with the Center for Native American and Indigenous Studies, the Center for the American West, and the Department of Ethnic Studies.

Aside from teaching fiction and screenwriting workshops, Jones teaches courses on comic books, the haunted house, the slasher, the zombie and the werewolf. His fiction navigates the spaces between the commercial and the literary, often using the tropes of horror and fantasy and science fiction and the western and noir in unconventional ways. He says he's not running out of stories anytime soon, either.

Kenneth P. Wright Jr., whose talk is titledSleep for Optimal Health and Performance,is a professor in the Department of Integrative Physiology and the director of the Sleep and Chronobiology Laboratory at CU-Boulder.

Wright received a BS in psychology from the University of Arizona (1990) and a PhD in Behavioral Neuroscience from Bowling Green State University (1996). Following postdoctoral training in the Division of Sleep Medicine at Harvard Medical School and Brigham and Womens Hospital, he served on the faculty at Harvard Medical School prior to joining the faculty at CU Boulder in 2002.

Wright has more than 25 years of experience in sleep and circadian research, has led individual and multicenter/transdisciplinary team projects, and has participated in multicenter clinical trials. His research aims to understand the physiology of sleep and circadian rhythms in humans and the health and safety consequences of sleep and circadian disruptionsuch as, metabolic dysregulation, impaired cognition, and compromised performance.

Wrights research also explores strategies to promote sleep, enhance alertness and maintain health and safety when sleep and circadian rhythms are challenged, as well as treatment strategies for patients with sleep and circadian related disorders.

He is a frequently invited speaker and media contact and has published more than 115 peer-reviewed articles. Wright manages a large undergraduate, graduate and postgraduate training program in sleep and circadian physiology at CU Boulder.

Wright has served in leadership, consulting, and advisory roles for government, professional, community, and commercial stakeholders, such as, the Sleep Disorders Research Advisory Board of the National Institutes of Health, National Heart, Lung, and Blood Institute, and the Board of Directors of the Sleep Research Society. He also serves as a reviewer for numerous national and international granting agencies and scientific journals.

Robert Pasnauhas taught in the Department of Philosophy since 1999. His research concentrates on the history of philosophy, particularly the end of the Middle Ages and the beginnings of the modern era.

He is the editor of theCambridge History of Medieval Philosophyand ofOxford Studies in Medieval Philosophy. His most recent book,After Certainty: A History of Our Epistemic Ideals and Illusions(OUP 2017), is based on his Isaiah Berlin Lectures, delivered at Oxford University in 2014.

Pasnau is the founding director of the Benson Center for the Study of Western Civilization.

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Newly minted professors of distinction to be celebrated - CU Boulder Today

Physiology

Parkinson’s disease improved with both physical and cognitive exercises – The Star Online

January 30, 2020 medical

Parkinsons patients motor and non-motor symptoms were improved with a weekly exercise regimen that included physical and cognitive tasks, according to new research presented on Dec 16, 2019, at The Physiological Society early career conference Future Physiology 2019: Translating Cellular Mechanisms into Lifelong Health Strategies.

Parkinsons disease is a chronic neurodegenerative disease that can lead to disability and make it harder to lead an active lifestyle.

Previous research has shown that either physical or cognitive exercises are effective at improving and sustaining cognitive and/or physical function in people with Parkinsons.

However, doing different types of exercise (e.g. circuit training that also includes cognitive challenges) may be more beneficial in improving motor and non-motor symptoms.

Researchers at the University of Kent in the United Kingdom studied Parkinsons patients that performed a weekly multi-modal regime (physical and cognitive exercises).

This group participated in weekly exercise sessions for over a year and were assessed every four months for at least a year (some participants continued on for two or three years).

This once-a-week exercise programme with both physical and cognitive exercises for Parkinsons disease patients showed an improvement specifically in one-minute sit-to-stand tests and a cognitive test called MiniMental, but no other significant changes (i.e. no decline) in cognitive and physical health.

This is especially positive as Parkinsons is a degenerative disease, so the expected outcome, without any interventions for these symptoms, would be a decline.

These findings are important because they could allow Parkinsons patients to see improvements in their symptoms by correctly tailoring their exercise regimens to include both physical and cognitive exercise.

Anna Ferrusola-Pastrana, a researcher who was involved with the work said: "Finding the right set of exercises, both cognitive and physical, to improve Parkinsons treatment is an important step towards giving Parkinsons patients a better quality of life.

"This research is working towards honing this set of exercises, which can then potentially be performed by patients, with or without assistance at home.

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Parkinson's disease improved with both physical and cognitive exercises - The Star Online

Physiology

physIQ receives $500000 for its AI healthcare solutions – ITIJ

January 30, 2020 medical

Founded by Gary Conkright, an alumnus of Purdues College of Engineering, physIQ (which is incidentally a Purdue University-affiliated company) applies AI to real-time physiological data from wearable sensors in order to develop solutions that will improve healthcare outcomes.

The money that physIQ has received is from Purdue Research FoundationsFoundry Investment Fund, which was established in 2014 through a partnership between Purdue research Foundations and Cook Medical. The goal of the fund is to add critical capital for the transition from the discovery of a promising technology to founding a viable life sciences company. In the past five years, the Foundry Investment Fund has invested nearly $5 million in 13 companies.

The Foundry Investment Fund plays an important role in attracting interest in Purdue-affiliated life sciences companies, said John Hanak, Managing Director ofPurdue Ventures. Gary Conkrights team at physIQ offers a great example of the kinds of technology and products that align perfectly with the goals of the fund.

Commenting on the funding, Conkright noted that, one of the many exciting factors of the collaboration is that it facilitates a closer alignment with some of Purdues experts. One specific example is the direct collaboration with the school of biomedical engineering, which will accelerate physIQs work in areas in which they excel. In tandem, we are providing real-world use cases to the schools research efforts, he said.

This investment is an incredible show of support and confidence in our technology and our vision from the Purdue Research Foundation, Conkright added. The Foundations support will help us continue to lead the way in changing how healthcare is developed and delivered through FDA-cleared physiology analytics.

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physIQ receives $500000 for its AI healthcare solutions - ITIJ

Physiology

Study advances the understanding of capillary regression – News-Medical.net

January 30, 2020 medical

Many diseases arise from abnormalities in our capillaries, tiny exquisitely branching blood vessel networks that play a critical role in tissue health. Researchers have learned a lot about the molecular communication underlying capillary formation and growth, but much less is understood about what causes these critical regulators of normal tissue function to collapse and disappear.

"Capillary regression (loss) is an underappreciated, yet profound, feature of many diseases, especially those affecting organs requiring a lot of oxygen to work properly," said George Davis, MD PhD, professor of molecular pharmacology and physiology at the University of South Florida Health (USF Health) Morsani College of Medicine, Tampa, Fla.

"If we know how blood vessels are altered or begin to break down we should be able to fix it pharmacologically," said Dr. Davis, a member of the USF Health Heart Institute.

A team led by Dr. Davis advanced the understanding of how capillaries regress in a study published Dec. 19 in the American Heart Association journal Arteriosclerosis, Thrombosis, and Vascular Biology. The USF Health researchers worked with the laboratory of Courtney Griffin, PhD, at Oklahoma Medical Research Foundation.

The researchers discovered that three major proinflammatory mediators - interlukin-1 beta (IL-1), tumor necrosis factor alpha (TNF) and thrombin - individually and especially when combined, directly drive capillary regression (loss) known to occur in diseases such as hypertension, diabetes, cardiovascular diseases, neurodegenerative diseases and malignant cancer. They also identified combinations of drugs - neutralizing antibodies to specifically block IL-1 and TNF, or combinations of pharmacologic inhibitors - that significantly interfered with capillary regression.

Capillaries, our body's tiniest and most abundant blood vessels, connect arteries with veins and exchange oxygen, nutrients and waste between the bloodstream and tissues throughout the body. The Davis laboratory grows three-dimensional human "blood vessel networks in a dish" under defined, serum-free conditions to delve into the complexity of how capillaries take shape to sustain healthy tissues. Lately, his team has begun applying what they've learned using this innovative in vitro model to attack, and possibly protect against, diseases.

For this study the researchers cultured two types of human cells: endothelial cells, which line the inner surface of capillaries, and pericytes, which are recruited to fortify the outer surface of the endothelial-lined tubes. Cross-communication between these cells controls how the blood vessel networks emerge, branch and stabilize. Macrophages, a type of immune cell, were activated in the cell culture media to simulate a tissue-injury environment highly conducive to capillary regression.

Among the key study findings:

- Macrophage-derived molecules IL-1 and TNF, combined with thrombin, selectively cause endothelial-lined capillary tube networks to regress; however, pericytes continue to proliferate around the degenerating capillaries. Why the pericytes are spared remains an intriguing question to be answered, but Dr. Davis suggests these more resilient cells may be left behind to help repair tissue damaged by inflammation.

- IL-1 and TNF, combined with thrombin, induce a unique set of molecular signals contributing to the loss of blood vessels. This "capillary regression signaling signature" is opposite of the physiological pathways previously identified by Dr. Davis and others as characterizing capillary formation and growth.

- Certain drug combinations (two were identified by the researchers) can block the capillary loss promoted by IL-1, TNF and thrombin.

The USF Health researchers found several other proinflammatory molecules that promoted capillary loss, but none proved as powerful as IL-1, TNF and thrombin, especially when all three were combined.

Antibodies to counteract the effects of IL-1 and TNF are already used to treat patients with some inflammatory diseases, including atherosclerosis, rheumatoid arthritis, and Crohn's disease. And physicians prescribe direct thrombin inhibitors for certain patients with atrial fibrillation, deep vein thrombosis and pulmonary embolism.

These drugs are out there and they work. Our data suggests that, if combined, they may actually prevent vessel breakdown (earlier in the disease process) and improve outcomes."

Dr. George Davis, a member of the USF Health Heart Institute

The USF Health team plans to investigate how abnormal capillary response may influence the loss of cells and tissues specific to disease states like sepsis, ischemic heart disease and stroke. Their model of 3D blood vessel networks can also be easily used to screen more potential drug candidates, Dr. Davis said. "We've identified some promising (existing) drugs to rescue capillary regression -- but there may be more therapeutic opportunities."

Source:

Journal reference:

Koller, G.M., et al. (2019) Proinflammatory Mediators, IL (Interleukin)-1, TNF (Tumor Necrosis Factor) , and Thrombin Directly Induce Capillary Tube Regression. Arteriosclerosis, Thrombosis, and Vascular Biology. doi.org/10.1161/ATVBAHA.119.313536.

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Study advances the understanding of capillary regression - News-Medical.net

Physiology

‘Like 5’4 and a complete badass’ – The Daily Evergreen

January 30, 2020 medical

In the Physical Education Building, junior and black beltAndrea Barcenas teaches karate, boxing and other forms of self-defense.

Barcenas practicesKaratedo Doshinkan, which she said pulls the best aspects of other martial artsforms and incorporate it into one. While she also teaches judo, Kyokushinkarate, Muay Thai and boxing in her class, Karatedo Doshinkan is what shesbeen training in for 15 years.

I try to make [the class] as fun and incorporating aspossible, Barcenas said. One thing I didnt like when I was younger was, ofcourse, a 6-year-old doesnt want to stand for three hours. But you learn, itsdiscipline. So yeah its tough, but its also fun.

Barcenas has been involved in martial arts since she wasfour, encouraged by her father, who did martial arts when he was a child.

Barcenas said she didnt like karate until she turned 13,where she started learning more about the outside world and saw its value.

One time my sister and me were walking home from schooland for some reason someone decided to choke her, and he said it was for fun,Barcenas said. And I was like Well, why dont you do that to me since its fun,and then this is, like, elementary [school] I grabbed him and I threw himover my back, on the pavement in front of all of the security guards, all ofthe teachers, all of the parents, and then I just grabbed [my sisters] handand walked away.

Right now Barcenas studies mechatronics robotics andautomation engineering, which WSU does not offer as a major but does providethe foundations for, Barcenas said. After college, Barcenas said she wants towork in animatronics, robotics or programming.

She said she is still considering opening a dojo butbesides needing the permission of her sensei, she said she doesnt think shesat that level yet.

Even after I got [my black belt, and] after 12 years itstill wasnt enough, but I think everyones definition of enough is different,Barcenas said. I feel like my bar is all the way up here, so, unrealisticallyhigh expectations.

Ive been in situations where Ive had a gun held to my face. I never want that to happen again.

Jillian Lenicka, WSUfreshman nutrition and exercise physiology major and student of Barcenas,said she is an energetic and passionate person when it comes to self-defense.

Computer science major and president of Judo Club MatthewMolitor said he first met Barcenas while she was doing a demonstration at amartial arts symposium, where she was breaking wooden boards and cinder blocks.

I was blown away by that because she was unassuming, like 54, and a complete badass,Molitor said. It kind of gave me a respect for karate.

Barcenas said she sees karate as a spiritual activity,something that shes incorporated into her life mentally, spiritually,physically, even if she doesnt do it every day.

Im terrified of the outside world sometimes, thats whyI wanted to learn to protect myself, she said. Because Ive been insituations where Ive had a gun held to my face. I never want that to happenagain.

Barcenas calls self-defense a security blanket, andsaid its important to learn to protect oneself if a dangerous situation comesup.

If youre like me and your mind runs at a hundred milesan hour youre always thinking about what could happen, Barcenas said. Inever want to be in that situation again, therefore Ill never let myself getin that situation again. If it happens, theyre not coming out of it.

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'Like 5'4 and a complete badass' - The Daily Evergreen

Physiology

MBBS Students scattered magnificence with flower rangoli, know the information – Sahiwal Tv

January 30, 2020 medical

The tennis garden of King George Medical University was embellished with flowers on the event of Vasant Panchami. A lovely view of gorgeous flowers was being constructed throughout.

Girl college students awoke all through the evening and made a rangoli of flowers, Saraswati Puja was completed within the morning courtyard. After which Medicose fiercely took a selfie in yellow garments.

Vice Chancellor Prof. MLB Bhat paid obeisance to mom Saraswati after performing and worshiping her. The Vice Chancellor advised the scholars in regards to the significance of Vasant Panchami and stated that Vasant Panchami is a pageant of worship of Mother Saraswati, which offers us with data, knowledge, knowledge and fame.

After the Saraswati Pujan, a program of Yajna, Prasad distribution was additionally organized.

->In which all the scholars together with medical college medical doctors, academics, college students of MBBS participated enthusiastically.

On this event, the complete courtyard was embellished with colourful Rangoli by the scholars of MBBS 2018 batch with the contribution of the scholars of MBBS 2019 batch.

The organized group, primarily fashioned by all the scholars of the 2018 batch, contributed to all the enjoyment and enthusiasm in organizing this system.

On this event, Rangoli competitors for the scholars of MBBS 2019 batch was organized by the Department of Physiology, together with Prof. Sunita Tiwari, Head of the Department of Physiology, Dr. Archana Ghilliyal, Acharya, and Professor and Principal of Physiology, Student Welfare, Prof. Narsingh Verma. Gave full contribution and steerage. Along with this, about 80 college students from four groups participated in Rangoli competitors.

Cartoon making competitors, collage making and pot portray competitors have been additionally organized on this event. In the stated program, former Principal of KGMU, Prof. AM Kar, inspired the scholars collaborating in varied competitions and honored the winners of the competitors by giving them prizes.

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MBBS Students scattered magnificence with flower rangoli, know the information - Sahiwal Tv

Physiology

The heroines STEM: Ten women in science you should know – East Bay Times

January 30, 2020 medical

By Lauren Kent | CNN

Science is often considered a male-dominated field.

In fact, according to United Nations data, less than 30% of scientific researchers worldwide are women.

Studies have shown that women are discouraged from, or become less interested in, entering the fields of science, technology, engineering and math (STEM) beginning at a young age. And according to the Pew Research Center, women remain underrepresented in engineering, computer science and physical science.

But despite challenges of gender discrimination and lack of recognition in the scientific community, countless inspiring women in these fields have made historic contributions to science and helped advance understanding of the world around us. Many were not recognized in their own lifetimes, but their achievements have helped generations of female scientists to come.

We all learned about Marie Curie and Jane Goodall, but here are 10 more women in science you should know.

American chemist Alice Ball was the first woman and first African American to receive a masters from the University of Hawaii and went on to become the universitys first female chemistry professor. At just 23 years old, Ball developed a groundbreaking treatment for leprosy a disease which previously had little chance of recovery and forced victims into exile.

Prior to Balls research on leprosy, the best treatment available was chaulmoogra oil, which was difficult for patients to ingest or apply topically and too thick to inject. While working as a research assistant at Kalihi Hospital in Hawaii, Ball developed an easily injectable form of the oil that ultimately saved countless lives and became the best treatment for leprosy until the 1940s.

Unfortunately she died before she was able to publish the findings, and the president of the University of Hawaii attempted to claim the research as his own until Balls former supervisor publicly spoke out that she deserved the credit for the lifesaving injection. It wasnt until the 21st century that her achievements were fully recognized and the governor of Hawaii declared February 29 Alice Ball Day.

Legend has it that British chemist and DNA researcher Rosalind Franklin knew she wanted to be a scientist since she was 15 years old. That dream went on to become a reality when she was offered a prestigious scholarship to Kings College London, where she became an expert in the X-ray crystallography unit.

Franklins research data was the first to demonstrate the basic dimensions of DNA strands and reveal the molecule was in two matching parts, running in opposite directions. Her data was used by James Watson and Francis Crick to get their research on the DNA model across the finish line, and was published separately as supporting data alongside Watson, Crick and Maurice Wilkins research articles in Nature.

Many people in the scientific community argue that Franklin should have been awarded a Nobel Prize alongside Watson, Crick and Maurice Wilkins, who won the 1962 Nobel Prize in Physiology or Medicine for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material. Unfortunately, Franklin died from ovarian cancer in 1958, just four years before the prize was awarded, even though at the time the organization could have awarded it posthumously.

Dorothy Hodgkin was a British chemist on the cutting edge of X-ray crystallography. In 1964, Hodgkin became the first and only British woman to win the Nobel Prize in Chemistry for her determinations by X-ray techniques of the structures of important biochemical substances.

Throughout her career, she made numerous breakthrough discoveries, including the atomic structure of penicillin, the structure of vitamin B12 and the structure of insulin. Hodgkin also spent decades improving X-ray crystallography techniques, which made it possible for her to complete her innovative research on insulin and improve treatments for diabetes.

She also became the second woman to win the UKs prestigious Order of Merit in 1965. While Hodgin was a professor at Oxford University, she even mentored Prime Minister Margaret Thatcher, who would go on to win the Order of Merit herself.

Grace Hopper was a trailblazing computer programmer who helped develop multiple computer languages and is considered one of the first programmers of the modern computing age.

Armed with a masters degree and PhD in mathematics from Yale, Hopper went on to have an influential career in the private sector and the US Navy. She joined the US Naval Reserve in 1943 to help with the American war effort, and throughout WWII she worked in a prestigious lab responsible for top-secret calculations such as calibrating minesweepers, calculating the ranges of anti-aircraft guns and checking the math behind the creation of the plutonium bomb.

Her career also contributed to modern computer vernacular. While Hopper was developing some of the earliest electromechanical computers MARK I and MARK II she dismantled a malfunctioning computer to find that a dead moth was causing the problem. She became the first person to call computer problems bugs in the system.

American botanist Barbara McClintock was responsible for several groundbreaking discoveries in the field of genetics following her decades-long career studying the genetic structure of maize. McClintock studied how genetic characteristics are passed down through generations, eventually uncovering that some genes could be mobile.

In the 1940s and 1950s, McClintocks research revealed that genetic elements could sometimes move on a chromosome and thus cause nearby genes to activate. But it wasnt until decades later that scientists apart from maize specialists understood and recognized the immense value of her discovery.

McClintock was awarded the National Medal of Science in 1971 and won the Nobel Prize in Physiology or Medicine in 1983 for her discovery of mobile genetic elements, now called transposons.

Austrian physicist Lise Meitner contributed significant advancements to the field of nuclear physics. She was also the first woman to become a physics professor in Germany.

Meitners work on nuclear fission was instrumental in her longtime research collaborator Otto Hahn winning the 1944 Nobel Prize in Chemistry, so much so that many scientists later argued it was unfair for her contributions to not have been recognized equally by the Nobel Committee. Meitner was also an advocate for the peaceful use of atomic energy and flatly refused to work on the Manhattan Project because she strongly opposed using fission to create an atom bomb.

Today, multiple prestigious awards in physics are named in honor of Meitner and she even has a chemical element meitnerium named after her.

NASA astronaut Sally Ride became the first American woman in space, serving as a mission specialist on the space shuttle Challenger in 1983. At 32 years old, she was also the youngest American to ever leave the atmosphere. (She wasnt the first woman in space, though that title belongs to Soviet cosmonaut Valentina Tereshkova.)

After the Challenger disaster in 1986, in which an explosion occurred shortly after takeoff and claimed the lives of seven astronauts, Ride served on the Rogers Commission, which investigated the tragedy. She also helped investigate the space shuttle Columbia disaster in 2003, during which the shuttle disintegrated as it re-entered the atmosphere, making Ride the only person to serve on both investigation commissions.

Ride went on to have an award-winning career as a public servant and as a physics professor at the University of California, San Diego. She also founded Sally Ride Science, an organization that aims to inspire young people in STEM, and she wrote several books about her experience in space to teach kids about science.

Pharmaceutical chemist Tu Youyous discovery of a new malaria treatment has saved millions of lives. Tu, who studied traditional Chinese and herbal medicines, found a reference in ancient medical texts to using sweet wormwood to treat intermittent fevers a symptom of malaria.

Tu and her research team were able to extract a malaria-inhibiting substance called artemisinin (or qinghaosu in Chinese) from wormwood. She even volunteered to be the first human subject to test the substance. Since her discovery of artemisinin in the 1970s, antimalarial drugs based on the substance have saved millions of lives.

Tu is now chief scientist at the China Academy of Traditional Chinese Medicine a position she reached without a medical degree, a PhD, or research training abroad. She won the 2015 Nobel Prize in Physiology or Medicine for her discovery, which has been deemed arguably the most important pharmaceutical intervention in the last half-century by the Lasker Foundation for medical research.

Maria Winkelmann was a pioneer in German astronomy. In 1902, she became the first woman to discover a new comet. Sadly, her husband Gottfried Kirch published the discovery in his own name, and did not publicly reveal her as the true source of the comet discovery until years later.

However, Winkelmann was still widely recognized as an accomplished scientist during her time, and her research and observations on sunspots, Aurora Borealis and comets were met with high regard. She also took on an active role in improving the Berlin Academy of Science, where her husband served as the principal astronomer.

But years later the Academy turned on her. While serving as an assistant to her son at the Berlin Observatory, Academy members complained she took on too prominent of a role and forced her into retirement ending her astronomy career in 1716, aged 46.

Chinese-American physicist Chien-Shiung Wu is credited with disproving one of the basic laws of physics, called conservation of parity. Prior to Wus work, the laws of physics stated that all objects and their mirror images behaved in the same way, symmetrically, meaning that nature could not distinguish between right and left. Wus breakthrough research revealed that during the process of radioactive decay, decaying identical nuclear particles didnt always behave symmetrically.

She also worked on the Manhattan Project, helping develop the process for separating uranium metal and developing better instruments to measure nuclear radiation.

In 1973, Wu became the first woman to lead the American Physical Society, and in 1975 she received the National Medal of Science. Her book Beta Decay remains a standard textbook for nuclear physics students.

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The heroines STEM: Ten women in science you should know - East Bay Times

Physiology

Skeletal system 1: the anatomy and physiology of bones – Nursing Times

January 28, 2020 medical

Bones are an important part of the musculoskeletal system. This article, the first in a two-part series on the skeletal system, reviews the anatomy and physiology of bone

The skeletal system is formed of bones and cartilage, which are connected by ligaments to form a framework for the remainder of the body tissues. This article, the first in a two-part series on the structure and function of the skeletal system, reviews the anatomy and physiology of bone. Understanding the structure and purpose of the bone allows nurses to understand common pathophysiology and consider the most-appropriate steps to improve musculoskeletal health.

Citation: Walker J (2020) Skeletal system 1: the anatomy and physiology of bones. Nursing Times [online]; 116: 2, 38-42.

Author: Jennie Walker is principal lecturer, Nottingham Trent University.

The skeletal system is composed of bones and cartilage connected by ligaments to form a framework for the rest of the body tissues. There are two parts to the skeleton:

As well as contributing to the bodys overall shape, the skeletal system has several key functions, including:

Bones are a site of attachment for ligaments and tendons, providing a skeletal framework that can produce movement through the coordinated use of levers, muscles, tendons and ligaments. The bones act as levers, while the muscles generate the forces responsible for moving the bones.

Bones provide protective boundaries for soft organs: the cranium around the brain, the vertebral column surrounding the spinal cord, the ribcage containing the heart and lungs, and the pelvis protecting the urogenital organs.

As the main reservoirs for minerals in the body, bones contain approximately 99% of the bodys calcium, 85% of its phosphate and 50% of its magnesium (Bartl and Bartl, 2017). They are essential in maintaining homoeostasis of minerals in the blood with minerals stored in the bone are released in response to the bodys demands, with levels maintained and regulated by hormones, such as parathyroid hormone.

Blood cells are formed from haemopoietic stem cells present in red bone marrow. Babies are born with only red bone marrow; over time this is replaced by yellow marrow due to a decrease in erythropoietin, the hormone responsible for stimulating the production of erythrocytes (red blood cells) in the bone marrow. By adulthood, the amount of red marrow has halved, and this reduces further to around 30% in older age (Robson and Syndercombe Court, 2018).

Yellow bone marrow (Fig 1) acts as a potential energy reserve for the body; it consists largely of adipose cells, which store triglycerides (a type of lipid that occurs naturally in the blood) (Tortora and Derrickson, 2009).

Bone matrix has three main components:

Organic matrix (osteoid) is made up of approximately 90% type-I collagen fibres and 10% other proteins, such as glycoprotein, osteocalcin, and proteoglycans (Bartl and Bartl, 2017). It forms the framework for bones, which are hardened through the deposit of the calcium and other minerals around the fibres (Robson and Syndercombe Court, 2018).

Mineral salts are first deposited between the gaps in the collagen layers with once these spaces are filled, minerals accumulate around the collagen fibres, crystallising and causing the tissue to harden; this process is called ossification (Tortora and Derrickson, 2009). The hardness of the bone depends on the type and quantity of the minerals available for the body to use; hydroxyapatite is one of the main minerals present in bones.

While bones need sufficient minerals to strengthen them, they also need to prevent being broken by maintaining sufficient flexibility to withstand the daily forces exerted on them. This flexibility and tensile strength of bone is derived from the collagen fibres. Over-mineralisation of the fibres or impaired collagen production can increase the brittleness of bones as with the genetic disorder osteogenesis imperfecta and increase bone fragility (Ralston and McInnes, 2014).

Bone architecture is made up of two types of bone tissue:

Also known as compact bone, this dense outer layer provides support and protection for the inner cancellous structure. Cortical bone comprises three elements:

The periosteum is a tough, fibrous outer membrane. It is highly vascular and almost completely covers the bone, except for the surfaces that form joints; these are covered by hyaline cartilage. Tendons and ligaments attach to the outer layer of the periosteum, whereas the inner layer contains osteoblasts (bone-forming cells) and osteoclasts (bone-resorbing cells) responsible for bone remodelling.

The function of the periosteum is to:

It also contains Volkmanns canals, small channels running perpendicular to the diaphysis of the bone (Fig 1); these convey blood vessels, lymph vessels and nerves from the periosteal surface through to the intracortical layer. The periosteum has numerous sensory fibres, so bone injuries (such as fractures or tumours) can be extremely painful (Drake et al, 2019).

The intracortical bone is organised into structural units, referred to as osteons or Haversian systems (Fig 2). These are cylindrical structures, composed of concentric layers of bone called lamellae, whose structure contributes to the strength of the cortical bone. Osteocytes (mature bone cells) sit in the small spaces between the concentric layers of lamellae, which are known as lacunae. Canaliculi are microscopic canals between the lacunae, in which the osteocytes are networked to each other by filamentous extensions. In the centre of each osteon is a central (Haversian) canal through which the blood vessels, lymph vessels and nerves pass. These central canals tend to run parallel to the axis of the bone; Volkmanns canals connect adjacent osteons and the blood vessels of the central canals with the periosteum.

The endosteum consists of a thin layer of connective tissue that lines the inside of the cortical surface (Bartl and Bartl, 2017) (Fig1).

Also known as spongy bone, cancellous bone is found in the outer cortical layer. It is formed of lamellae arranged in an irregular lattice structure of trabeculae, which gives a honeycomb appearance. The large gaps between the trabeculae help make the bones lighter, and so easier to mobilise.

Trabeculae are characteristically oriented along the lines of stress to help resist forces and reduce the risk of fracture (Tortora and Derrickson, 2009). The closer the trabecular structures are spaced, the greater the stability and structure of the bone (Bartl and Bartl, 2017). Red or yellow bone marrow exists in these spaces (Robson and Syndercombe Court, 2018). Red bone marrow in adults is found in the ribs, sternum, vertebrae and ends of long bones (Tortora and Derrickson, 2009); it is haemopoietic tissue, which produces erythrocytes, leucocytes (white blood cells) and platelets.

Bone and marrow are highly vascularised and account for approximately 10-20% of cardiac output (Bartl and Bartl, 2017). Blood vessels in bone are necessary for nearly all skeletal functions, including the delivery of oxygen and nutrients, homoeostasis and repair (Tomlinson and Silva, 2013). The blood supply in long bones is derived from the nutrient artery and the periosteal, epiphyseal and metaphyseal arteries (Iyer, 2019).

Each artery is also accompanied by nerve fibres, which branch into the marrow cavities. Arteries are the main source of blood and nutrients for long bones, entering through the nutrient foramen, then dividing into ascending and descending branches. The ends of long bones are supplied by the metaphyseal and epiphyseal arteries, which arise from the arteries from the associated joint (Bartl and Bartl, 2017).

If the blood supply to bone is disrupted, it can result in the death of bone tissue (osteonecrosis). A common example is following a fracture to the femoral neck, which disrupts the blood supply to the femoral head and causes the bone tissue to become necrotic. The femoral head structure then collapses, causing pain and dysfunction.

Bones begin to form in utero in the first eight weeks following fertilisation (Moini, 2019). The embryonic skeleton is first formed of mesenchyme (connective tissue) structures; this primitive skeleton is referred to as the skeletal template. These structures are then developed into bone, either through intramembranous ossification or endochondral ossification (replacing cartilage with bone).

Bones are classified according to their shape (Box1). Flat bones develop from membrane (membrane models) and sesamoid bones from tendon (tendon models) (Waugh and Grant, 2018). The term intra-membranous ossification describes the direct conversion of mesenchyme structures to bone, in which the fibrous tissues become ossified as the mesenchymal stem cells differentiate into osteoblasts. The osteoblasts then start to lay down bone matrix, which becomes ossified to form new bone.

Box 1. Types of bones

Long bones typically longer than they are wide (such as humerus, radius, tibia, femur), they comprise a diaphysis (shaft) and epiphyses at the distal and proximal ends, joining at the metaphysis. In growing bone, this is the site where growth occurs and is known as the epiphyseal growth plate. Most long bones are located in the appendicular skeleton and function as levers to produce movement

Short bones small and roughly cube-shaped, these contain mainly cancellous bone, with a thin outer layer of cortical bone (such as the bones in the hands and tarsal bones in the feet)

Flat bones thin and usually slightly curved, typically containing a thin layer of cancellous bone surrounded by cortical bone (examples include the skull, ribs and scapula). Most are located in the axial skeleton and offer protection to underlying structures

Irregular bones bones that do not fit in other categories because they have a range of different characteristics. They are formed of cancellous bone, with an outer layer of cortical bone (for example, the vertebrae and the pelvis)

Sesamoid bones round or oval bones (such as the patella), which develop in tendons

Long, short and irregular bones develop from an initial model of hyaline cartilage (cartilage models). Once the cartilage model has been formed, the osteoblasts gradually replace the cartilage with bone matrix through endochondral ossification (Robson and Syndercombe Court, 2018). Mineralisation starts at the centre of the cartilage structure, which is known as the primary ossification centre. Secondary ossification centres also form at the epiphyses (epiphyseal growth plates) (Danning, 2019). The epiphyseal growth plate is composed of hyaline cartilage and has four regions (Fig3):

Resting or quiescent zone situated closest to the epiphysis, this is composed of small scattered chondrocytes with a low proliferation rate and anchors the growth plate to the epiphysis;

Growth or proliferation zone this area has larger chondrocytes, arranged like stacks of coins, which divide and are responsible for the longitudinal growth of the bone;

Hypertrophic zone this consists of large maturing chondrocytes, which migrate towards the metaphysis. There is no new growth at this layer;

Calcification zone this final zone of the growth plate is only a few cells thick. Through the process of endochondral ossification, the cells in this zone become ossified and form part of the new diaphysis (Tortora and Derrickson, 2009).

Bones are not fully developed at birth, and continue to form until skeletal maturity is reached. By the end of adolescence around 90% of adult bone is formed and skeletal maturity occurs at around 20-25 years, although this can vary depending on geographical location and socio-economic conditions; for example, malnutrition may delay bone maturity (Drake et al, 2019; Bartl and Bartl, 2017). In rare cases, a genetic mutation can disrupt cartilage development, and therefore the development of bone. This can result in reduced growth and short stature and is known as achondroplasia.

The human growth hormone (somatotropin) is the main stimulus for growth at the epiphyseal growth plates. During puberty, levels of sex hormones (oestrogen and testosterone) increase, which stops cell division within the growth plate. As the chondrocytes in the proliferation zone stop dividing, the growth plate thins and eventually calcifies, and longitudinal bone growth stops (Ralston and McInnes, 2014). Males are on average taller than females because male puberty tends to occur later, so male bones have more time to grow (Waugh and Grant, 2018). Over-secretion of human growth hormone during childhood can produce gigantism, whereby the person is taller and heavier than usually expected, while over-secretion in adults results in a condition called acromegaly.

If there is a fracture in the epiphyseal growth plate while bones are still growing, this can subsequently inhibit bone growth, resulting in reduced bone formation and the bone being shorter. It may also cause misalignment of the joint surfaces and cause a predisposition to developing secondary arthritis later in life. A discrepancy in leg length can lead to pelvic obliquity, with subsequent scoliosis caused by trying to compensate for the difference.

Once bone has formed and matured, it undergoes constant remodelling by osteoclasts and osteoblasts, whereby old bone tissue is replaced by new bone tissue (Fig4). Bone remodelling has several functions, including mobilisation of calcium and other minerals from the skeletal tissue to maintain serum homoeostasis, replacing old tissue and repairing damaged bone, as well as helping the body adapt to different forces, loads and stress applied to the skeleton.

Calcium plays a significant role in the body and is required for muscle contraction, nerve conduction, cell division and blood coagulation. As only 1% of the bodys calcium is in the blood, the skeleton acts as storage facility, releasing calcium in response to the bodys demands. Serum calcium levels are tightly regulated by two hormones, which work antagonistically to maintain homoeostasis. Calcitonin facilitates the deposition of calcium to bone, lowering the serum levels, whereas the parathyroid hormone stimulates the release of calcium from bone, raising the serum calcium levels.

Osteoclasts are large multinucleated cells typically found at sites where there is active bone growth, repair or remodelling, such as around the periosteum, within the endosteum and in the removal of calluses formed during fracture healing (Waugh and Grant, 2018). The osteoclast cell membrane has numerous folds that face the surface of the bone and osteoclasts break down bone tissue by secreting lysosomal enzymes and acids into the space between the ruffled membrane (Robson and Syndercombe Court, 2018). These enzymes dissolve the minerals and some of the bone matrix. The minerals are released from the bone matrix into the extracellular space and the rest of the matrix is phagocytosed and metabolised in the cytoplasm of the osteoclasts (Bartl and Bartl, 2017). Once the area of bone has been resorbed, the osteoclasts move on, while the osteoblasts move in to rebuild the bone matrix.

Osteoblasts synthesise collagen fibres and other organic components that make up the bone matrix. They also secrete alkaline phosphatase, which initiates calcification through the deposit of calcium and other minerals around the matrix (Robson and Syndercombe Court, 2018). As the osteoblasts deposit new bone tissue around themselves, they become trapped in pockets of bone called lacunae. Once this happens, the cells differentiate into osteocytes, which are mature bone cells that no longer secrete bone matrix.

The remodelling process is achieved through the balanced activity of osteoclasts and osteoblasts. If bone is built without the appropriate balance of osteocytes, it results in abnormally thick bone or bony spurs. Conversely, too much tissue loss or calcium depletion can lead to fragile bone that is more susceptible to fracture. The larger surface area of cancellous bones is associated with a higher remodelling rate than cortical bone (Bartl and Bartl, 2017), which means osteoporosis is more evident in bones with a high proportion of cancellous bone, such as the head/neck of femur or vertebral bones (Robson and Syndercombe Court, 2018). Changes in the remodelling balance may also occur due to pathological conditions, such as Pagets disease of bone, a condition characterised by focal areas of increased and disorganised bone remodelling affecting one or more bones. Typical features on X-ray include focal patches of lysis or sclerosis, cortical thickening, disorganised trabeculae and trabecular thickening.

As the body ages, bone may lose some of its strength and elasticity, making it more susceptible to fracture. This is due to the loss of mineral in the matrix and a reduction in the flexibility of the collagen.

Adequate intake of vitamins and minerals is essential for optimum bone formation and ongoing bone health. Two of the most important are calcium and vitamin D, but many others are needed to keep bones strong and healthy (Box2).

Box 2. Vitamins and minerals needed for bone health

Key nutritional requirements for bone health include minerals such as calcium and phosphorus, as well as smaller qualities of fluoride, manganese, and iron (Robson and Syndercombe Court, 2018). Calcium, phosphorus and vitamin D are essential for effective bone mineralisation. Vitamin D promotes calcium absorption in the intestines, and deficiency in calcium or vitamin D can predispose an individual to ineffective mineralisation and increased risk of developing conditions such as osteoporosis and osteomalacia.

Other key vitamins for healthy bones include vitamin A for osteoblast function and vitamin C for collagen synthesis (Waugh and Grant, 2018).

Physical exercise, in particular weight-bearing exercise, is important in maintaining or increasing bone mineral density and the overall quality and strength of the bone. This is because osteoblasts are stimulated by load-bearing exercise and so bones subjected to mechanical stresses undergo a higher rate of bone remodelling. Reduced skeletal loading is associated with an increased risk of developing osteoporosis (Robson and Syndercombe Court, 2018).

Bones are an important part of the musculoskeletal system and serve many core functions, as well as supporting the bodys structure and facilitating movement. Bone is a dynamic structure, which is continually remodelled in response to stresses placed on the body. Changes to this remodelling process, or inadequate intake of nutrients, can result in changes to bone structure that may predispose the body to increased risk of fracture. Part2 of this series will review the structure and function of the skeletal system.

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Iyer KM (2019) Anatomy of bone, fracture, and fracture healing. In: Iyer KM, Khan WS (eds) General Principles of Orthopedics and Trauma. London: Springer.

Moini J (2019) Bone tissues and the skeletal system. In: Anatomy and Physiology for Health Professionals. Burlington, MA: Jones and Bartlett.

Ralston SH, McInnes IB (2014) Rheumatology and bone disease. In: Walker BR et al (eds) Davidsons Principles and Practice of Medicine. Edinburgh: Churchill Livingstone.

Robson L, Syndercombe Court D (2018) Bone, muscle, skin and connective tissue. In: Naish J, Syndercombe Court D (eds) Medical Sciences. London: Elsevier

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Tortora GJ, Derrickson B (2009) The skeletal system: bone tissue. In: Principles of Anatomy and Physiology. Chichester: John Wiley & Sons.

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Skeletal system 1: the anatomy and physiology of bones - Nursing Times