How Space Travel Affects the Human Body

What challenges does the human body face in space? For over 50 years, NASA’s Human Research Program (HRP) has explored how space travel impacts the human body, paving the way for the future of space travel. Despite substantial research, many unknowns exist about the human body’s challenges during extended space travel.

Radiation exposure is a significant concern after being in space for long periods. Earth has a magnetic field that provides natural protection, but only if you are in the atmosphere. Still, space exposes crews to elevated radiation levels from particles trapped in Earth’s magnetic field, solar energetic particles, and galactic cosmic rays (NASA, 2024). These exposures could lead to both short- and long-term health consequences, including cancer and degenerative diseases. NASA is actively improving shielding, real-time radiation monitoring, and developing procedures to mitigate radiation effects on missions and Earth. For instance, they use advanced materials and technologies to enhance spacecraft shielding, and they have systems in place to monitor radiation levels in real-time during space missions (NASA, 2024). NASA collaborates with medical and scientific experts to develop countermeasures, such as drugs and dietary supplements, to protect astronauts from radiation exposure. NASA also uses cosmic rays in ground-based experiments to simulate space radiation and better understand the radiation risks astronauts face in space. This is crucial because it allows researchers to develop and test countermeasures to protect astronauts from harmful radiation. By replicating the space radiation environment on Earth, scientists can study its effects on biological systems and validate protective strategies before astronauts embark on their missions. 

Another effect comes from isolation and confinement during space missions, as they can create psychological and social challenges. The limited space and close-quarter living can affect mental health, team dynamics, and morale. To combat this, NASA has introduced innovative tools such as sleep monitors, LED (light-emitting diode) lighting systems to help regulate circadian rhythms, and self-assessment vigilance tests to counter these effects. (NASA, 2024). Additionally, virtual reality for relaxation and activities such as maintaining space gardens is beneficial for mental well-being. This helps because training focusing on communication and cross-cultural understanding further aids astronauts in coping with the stresses of long-term mission isolation.

By addressing physical and mental health challenges, NASA aims to ensure astronauts can thrive and complete their missions safely and effectively. Factors like noise exposure during launch, flight, and landing can lead to hearing loss, and the absence of standing causes the soles of the feet to lose calluses, becoming softer and more sensitive to pressure. Astronauts at the International Space Station (ISS) develop calluses on the tops of their feet due to the frequent use of footholds. Additionally, the confined and controlled environment of the ISS can lead to the growth of microbes on surfaces and astronauts’ skin. This microbial growth and a potentially weakened immune system in space can cause skin irritation, rashes, or infections. Maintaining hygiene and regularly cleaning the living space is essential to mitigate these issues and ensure the health and comfort of astronauts (Baylor College Of Medicine, 2023). To combat noise exposure, which can lead to hearing loss, space organizations like NASA have implemented strict acoustic guidelines for the ISS, limiting continuous noise levels to 72 dBA during work periods. The 72 dBA limit set by NASA on the ISS measures sound intensity in decibels adjusted for the sensitivity of human hearing (dBA). This level protects astronauts from potential hearing damage from prolonged noise exposure (NASA, 2023). For context, 72 dBA is roughly equivalent to the noise level of a busy office or a quiet vacuum cleaner, which is loud enough to be noticeable but not excessively harmful over short periods. Measures include using acoustic dosimeters (devices used to measure and monitor noise exposure over time), improving equipment insulation, and installing quieter ventilation systems​. To mitigate hearing loss from noise during launch and flight, NASA’s Acoustics Office focuses on reducing sound at its source and using sound-dampening materials in spacecraft design (NASA, 2023).

The distance from Earth is another major challenge for space travel, particularly for missions that venture beyond low orbit, 1,200 miles above Earth (NASA, 2024). While the ISS orbits at a height of just 240 miles, Mars is about 140 million miles away, leading to communication delays of up to 22 minutes for messages sent one way. This vast distance necessitates astronauts to be exceptionally self-reliant regarding medical procedures and problem-solving. To equip them for these challenges, NASA provides training in various skills, including how to create IV solutions and perform ultrasounds to assess organ health. Additionally, advanced tools and the potential use of artificial intelligence are being explored to aid real-time medical assistance decision-making.

Adjusting to different gravity environments adds further complications. The spacecraft’s harsh and confined environment presents risks such as changes in microbial behavior and increased stress hormone levels, which can weaken the immune system. Missions to Mars will involve experiencing weightlessness during transit, adapting to Mars’ one-third gravity, and eventually returning to Earth’s full gravity. These changes can influence coordination, muscle strength, and bone density. Extended time in microgravity (such as on the ISS) can lead to fluid shifts that may affect vision and increase the likelihood of kidney stones. While these effects are temporary, they are still dangerous if not tended to correctly. To mitigate these risks, rigorous exercise routines, compression garments, and continuous medical monitoring are implemented to promote bone and muscle health (JAXA n.d.).

Finally, NASA implements thorough air quality monitoring, microbial assessments, and sanitation protocols to safeguard astronaut health. Preventative strategies, including pre-mission quarantines and flu vaccinations, further enhance crew protection (NASA, 2023).

As NASA prepares for its Artemis mission to the Moon in September 2025, these efforts will provide critical data to help prepare for an even more ambitious Mars expedition. Through ongoing research and technological innovation, NASA is laying the groundwork for a safe and sustainable future in deep space exploration.

References

Baylor College of Medicine. www.bcm.edu/academic-centers/space-medicine/translational-research-institute/space-health-resources/how-the-body-changes-in-space.

GCELT. 4 Oct. 2024, gcelt.org/is-72db-loud-a-comprehensive-guide-to-decibel-levels-in-everyday-life/?form=MG0AV3.

JAXA. 2021, humans-in-space.jaxa.jp/en/life/health-in-space/body-impact/#:~:text=Bones%20and%20muscles%20weaken,muscles%20of%20your%20lower%20body. Accessed 21 Nov. 2024.

NASA. 7 Apr. 2024, www.nasa.gov/humans-in-space/leo-economy-frequently-asked-questions/#:~:text=Low%20Earth%20orbit%20(LEO)%20encompasses,(2%2C000%20km)%20or%20less. Accessed 21 Nov. 2024.

NASA. 2 Feb. 2021, www.nasa.gov/humans-in-space/the-human-body-in-space/. Accessed 21 Nov. 2024.

NASA. 23 Jan. 2023, www.nasa.gov/humans-in-space/experiments-to-unlock-how-human-bodies-react-to-long-space-journeys/.

NASA. 28 June 2023, www.nasa.gov/general/galactic-cosmic-ray-simulator-brings-space-down-to-earth/?form=MG0AV3.

Saving Pandas: One Cell at a time

With only 2,000 giant pandas remaining in the wild, the species face significant threats from habitat destruction, human encroachment, and limited genetic diversity. The question is, how can they be saved? Researchers have been actively seeking solutions to preserve this beloved species. In a promising discovery, a team of biologists has successfully converted panda skin cells into “induced pluripotent stem cells” (iPSCS),  cells that can be transformed into almost any other cell in the body. This research is a monumental step forward in creating primordial germ cells, the biological predecessors to sperm and egg cells, thereby paving the way for new reproductive methods. This research holds the potential not only to breed giant pandas but also to treat diseases and expand the genetic diversity of these giant pandas (Phys.org, 2024).

Induced pluripotent stem cells, or iPSCs, are adult cells reprogrammed to revert to a pluripotentstate, meaning they can differentiate easily. This means the cells have the potential to turn into almost any cell type in the body. Originally developed in 2006 by Shinya Yamanaka and Kazutoshi Takahashi at Kyoto University (Embryo Project, 2006), iPSCs are now used in various places in regenerative medicine and conservation biology. Unlike embryonic stem cells (ESCs), which are harvested from embryos, iPSCs offer a more “moral” alternative as they do not require the destruction of an embryo and can be sourced from adult tissues, such as skin or blood cells. iPSCs have shown promise in other endangered species. Researchers have successfully created iPSCs from rare species like the northern white rhino, Tasmanian devil, and even a rare zebra, showing the huge role that iPSCs can play in conserving species (Science.org, 2024). By creating cells that can eventually mature into reproductive cells or even entire organs, iPSCs are vital in the preservation of species. The adaptability of iPSCs for such applications has opened new avenues in conservation and biodiversity research. (Phys.org, 2024).

For the giant panda iPSC research, the team selected fibroblast cells, a type of skin cell integral to the structure and function of the skin. Fibroblasts produce collagen and also play a role in tissue repair. These cells are ideal for iPSC creation because they are accessible and can be sourced without invasive procedures.  Transforming fibroblasts into iPSCs, however, is not straightforward. Each animal species requires a unique reprogramming protocol because the transcription factors and reprogramming conditions vary across species. For giant pandas, scientists had to identify specific factors that would make the fibroblasts turn back into their pluripotent state. (Phys.org, 2024)

To convert giant panda fibroblasts into iPSCs, researchers introduced a carefully chosen combination of transcription factors and a specialized microRNA cluster known to aid in reprogramming. This microRNA cluster, when combined with the appropriate transcription factors, helped activate genes within the fibroblasts to reprogram them back to an embryonic-like, pluripotent state (Science.org, 2024).

There are two different kinds of iPSCs: naïve and primed. The former are early-stage, highly flexible cells that can easily form multiple cell types or even entire organisms under specific conditions, while the latter are further along the differentiation pathway. In this study, the researchers achieved a primed pluripotent state in panda iPSCs. This state is vital because it allows the iPSCs to differentiate into specialized cells needed for reproductive applications. However, the research team was not able to revert the iPSCs to their naïve state (Phys.org, 2024).

The giant panda iPSCs, or GPiPSCs, developed in this research demonstrated the ability to differentiate into the three primary germ layers—endoderm, mesoderm, and ectoderm—If successful, the ability to produce primordial germ cells from iPSCs could enhance breeding programs for pandas by creating reproductive cells without using invasive procedures. Additionally, GPiPSCs offer potential applications in medical research for these giant pandas, such as developing treatments for diseases that affect the panda population (Science News, 2024). 

This research on panda iPSCs opens promising pathways to conserving endangered species. The giant panda’s limited genetic diversity and reproduction challenges—joined with their isolated populations and inbreeding risks—make it imperative to try innovative approaches like stem cell research. Further research will focus on refining GPiPSC production methods, particularly in developing fully naïve iPSCs that can develop fully into chimeric embryos. Additionally, creating primordial germ cells from these iPSCs would offer flexibility in conservation, helping scientists support giant panda reproduction even in situations where normal breeding approaches are not possible (Science.org, 2024).

Not only is this discovery hugely impactful for the giant panda population, but for all animals around the world. Creating these cells could save numerous species on the verge of extinction. While each animal’s transcription process and microRNA are different, the fact that researchers made the discovery work for pandas is promising for other species (Science News, 2024).

References 

Liu, Y., Zhang, S., Zou, G., An, J., Li, Y., Lin, D., Wang, D., Li, Y., Chen, J., Feng, T., Li, H., Chen, Y., Zhang, M., Kumar, M., Wang, L., Hou, R., & Liu, J. (2024). Generation and characterization of giant panda induced pluripotent stem cells. Science Advances, 10(38). https://doi.org/10.1126/sciadv.adn7724

Yirka, B. (2024, September 23). Giant panda skin cells transformed into stem cells to help ensure their survival. Phys.org. https://phys.org/news/2024-09-giant-panda-skin-cells-stem.html

Journey Into Imagination

How does the mind control your imagination? Imagination is the key that unlocks the door to endless possibilities, a place in the mind where anything can happen. There are two main parts of a person’s brain that control their imagination: the prefrontal cortex, and the parietal and occipital lobes.The prefrontal cortex sits towards the front of the brain and is capable of sending signals all throughout the brain. It is an important piece of helping imagination work due to its ability to sync different parts of the brain (Hathaway & Newton, 2023). In addition to syncing up different parts of the brain, evidence shows that the prefrontal cortex controls much of the brain’s creativity, a factor in bolstering one’s imagination. The theory of mental synthesis proposes that the prefrontal cortex can also create completely new images from two previously existing images (Vyshedskiy & Dunn, 2015). The ability to form mental images, images that are formed in one of the parietal or occipital lobes (Wu & D’Costa, 2021), two lobes located in the middle and back of the brain. These lobes have control over sight, hearing, taste, and vision and are responsible for spacing images out into a person's imagination. The frontal lobe also helps with creative thinking, which is part of the imagination.

Creativity, the ability to create something using your imagination, is also extremely important to imagination (Smith, 2023). Additionally, creativity also uses the same pieces of the brain to function as the imagination, showing how deeply they are linked (JWU, 2023). One example of using imagination in life is creativity, the expansion of imagination into reality. Creativity is the use of imagination, so anything that is imagined is most likely going to move to the category of creativity.

Imagination is a mental process, meaning it is entirely contained within the brain. But what happens to the rest of the brain while someone is imagining? While you are imagining, multiple processes are activated in the brain. One effect of intense imagination is less precise brain activity and less spatial awareness because the brain focuses on receiving the mental images. These both go through similar processes, except that neurons are more spread out when imagining, making a slightly different image (Bridges, 2020). Furthermore, perception can also be distorted, such as changing colors or patterns. On the other hand, imagination improves human memory because it uses a similar function of information retrieval. This can delay dementia and help with improving the ability to recall previous images. It can also change neuron pathways by entering and changing memories as well as improving connections between the brain and other parts of the body.

Imagination and creativity can improve mental health by reducing stress, anxiety, and depression. Imagination helps innovate and fuel peoples’ desire to learn because it expands curiosity and gives space to build on questions and ideas (Futter, 2020). It keeps humans open-minded and in the mindset that anything is possible. Imagination can help solve problems and brainstorm ideas (Roos, 2023). Additionally, it allows for creativity and allows people to see images that no one has ever seen before (Vyshedskiy & Dunn, 2015). Imagination can improve many activities done in daily life such as memory, visualization, and brain coordination (Kober & Wood, 2017). 

References:

JWU. (2023, July 6). The Brain Region Behind Creativity and Imagination | JWU CPS. JWU College of Professional Studies. https://online.jwu.edu/blog/unlocking-power-mind-brain-region-behind-creativity-and-imagination/ 

Why Imagination? (2020, July 3). ImaginED. https://www.educationthatinspires.ca/why-imagination/

How do we imagine a novel object? (2016). ScienceDaily. https://www.sciencedaily.com/releases/2016/01/160105112105.htm 

De Souza, L. C., Guimarães, H. C., Teixeira, A. L., Caramelli, P., Levy, R., Dubois, B., & Volle, E. (2014). Frontal lobe neurology and the creative mind. Frontiers in Psychology, 5. https://doi.org/10.3389/fpsyg.2014.00761 

Bridges, C. (2020, July 9). Is what I see, what I imagine? Study finds neural overlap between vision and imagination. Web.musc.edu. https://web.musc.edu/about/news-center/2020/07/09/how-the-brain-sees-and-imagines-images 

Roos, J. (2023, February 21). Why Cultivating Curiosity & Imagination Benefits Your Business. Hult International Business School. https://www.hult.edu/blog/why-cultivating-curiosity-imagination-benefits-your-business/ 

Missing a Mind’s Eye: The Metacognition of Aphantasia. (2021, October 21). Grey Matters. https://greymattersjournal.org/missing-a-minds-eye-the-metacognition-of-aphantasia/ 

Kober, S. E., & Wood, G. (2017). How to Exercise by Imagining Movements. Frontiers for Young Minds, 5. https://doi.org/10.3389/frym.2017.00042

Hathaway, W. R., & Newton, B. W. (2020). Neuroanatomy, Prefrontal Cortex. PubMed; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK499919/  

Astrobiology

What if life outside Earth wasn’t truly fiction? Aliens have been an enigma since the beginning of time. Many find it unbelievable that life exists solely on Earth without any biota in the universe. Others find it absurd that scientists have not found any signs of life given the depth of astronomic discovery in the 20th and 21st centuries. This belief has taken on the form of the “Fermi Paradox,” highlighting that it is impossible that organisms on Earth are the only forms of life in the universe while it is also impossible that any other organisms in the universe exist because no scientific or mathematical discovery has shown life outside Earth (Shostak, 2019). This paradox has puzzled astrophysicists and ordinary stargazers alike. The confusion around life outside Earth has been expressed heavily in popular cinema such as Steven Spielberg’s E.T. and in literature under the science fiction genre, such as books by Isaac Asimov. 

Astrobiology is the field of science that intersects biology, the study of life, with astronomy, the study of space. Astrobiologists' primary focus is searching for extraterrestrial life and biota (living things) in the universe. Scientists do this by first understanding what conditions allow life to thrive. To survive, life typically requires liquid water and a “habitable zone” to live in, which is the sweet spot regarding the distance to a nearby star. The Earth exists in a habitable zone as it is rich in liquid water and is the right distance from the sun to allow organisms to thrive. There are also abnormal habitable zones such as the habitable zone on Saturn’s moon Titan which holds methane and ethane, other substances necessary for life. Titan is way farther than the normal habitable zone yet it still has some of the building blocks of life so astrobiologists have classified Titan as a habitable zone even though it is not the right distance from the sun (Shostak, 2019).

As astrobiologists have defined habitable zones, their main task is to search for habitable zones outside this solar system. Advanced telescopes such as the Hubble telescope can find thousands of exoplanets (planets outside our solar system), but there are strict criteria that narrow which exoplanets could be habitable. The first criterion is that the exoplanet is a smaller and Earth-likein appearance. The second criterion is whether astrobiologists can measure the light emitted from the atmosphere to determine whether there are sufficient oxygen and methane levels in the atmosphere (Shostak, 2019).

NASA has a specific astrobiology program that uses additional methodology to understand life outside Earth. NASA runs experiments on Earth to simulate life on other planets. For example, an experiment simulated Mars in the remote Atacama desert to search for biomarkers (signs of life) that could be found on Mars. In addition to the experiments on Earth, the Curiosity and Perseverance Rovers on Mars determined through testing samples of soil and rock that Mars was previously a wetter and warmer planet, thus, the possibility of once containing life is more prominent. Additionally, if astrobiologists can prove life existed on Mars previously, then there is likely life outside the solar system at the moment if there are two signs of life inside one system (Kaufman, 2022).

As NASA continues to conduct experiments, astrobiologists are focusing on analyzing using steps of a strategy that they created that they believe is crucial in determining life in the universe. The first step is to analyze inanimate materials such as rocks, minerals, or sediments on various planets to see if they are conducive to facilitating the reproduction of organisms. The second step is to consider how water could have appeared on different exoplanets, as water is key to life. Another way that NASA astrobiologists are trying to find life is by understanding the chemical structure of a planet to see if the chemical information reveals anything about whether life is feasible on the planet. The last idea is performing experiments to determine whether life can exist without carbon or methane to see if there are different ways that life can exist (Kaufman, 2022).

Astrobiology is an emerging field working to solve the puzzling questions of human's solitary existence in the universe. Understanding astrobiology for humanity and to better understand life in space can help answer science’s age-old questions about what life is outside of Earth. By understanding and creating a definition of what life looks like outside the universe, astrobiologists can be key in informing what life truly is and whether there are intelligent beings in the vastness of space.

References

Kaufman, M. (2022, October 12). Life, here and beyond. Astrobiology at NASA.

     Retrieved November 5, 2024, from https://astrobiology.nasa.gov/about/

Shostak, S. (2019, February 14). Astrobiology. Britannica. Retrieved November 5,

     2024, from https://www.britannica.com/science/astrobiology

BRCA: The Breast Cancer Gene

BRCA is a gene that heightens the risk for certain cancers in the body. There are different variants of the BRCA gene; BRCA 1 and BRCA 2 are the most prominent. The purpose of the gene is to repair damaged DNA, but mutations can put patients at a higher risk for cancer. These mutations are hereditary genes which makes smaller groups of people more susceptible to the gene, as there is the mixing of similar genetic pools. Getting genetic testing at 18 is a great way to assess the risks of getting BRCA-linked cancer. New ways to test involve a saliva test instead of getting blood drawn. Among people who get genetic testing for BRCA, women with the mutation are more likely to get the linked cancers than men, although many men get linked cancers from being BRCA-positive patients.

There are many cancers that BRCA mutations can create a heightened risk for cancers such as breast cancer (for both males and females), ovarian cancer, prostate cancer, fallopian tube cancer, primary peritoneal cancer, and pancreatic cancer. Some methods can reduce the risk of getting BRCA-related cancers such as surgical prevention and hormone therapy. 

Many BRCA-positive women choose to remove their breast tissue via prophylactic mastectomies and have their ovaries removed. Because of BRCA’s hereditary nature, BRCA 1 and BRCA 2 are most common in Ashkenazi Jewish populations with 2% of people, usually with a founder mutation. Norwegian, Dutch, and Icelandic populations also carry founder mutations, with different populations having different mutations. 

References:

https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet

https://www.hopkinsmedicine.org/health/conditions-and-diseases/breast-cancer/inherited-cancer-risk-brca-mutation

https://www.nationalbreastcancer.org/what-is-brca/#:~:-text=A%20BRCA%20mutation%20occurs%20when,helping%20to%20prevent%20breast%20cancer.

Mitosis

Mitosis is the process cells undergo to divide. The reason mitosis is crucial to all organisms is because it is what causes growth and repair within cells. For example, someone gets a paper cut and over time it begins to heal and the skin comes back. That is mitosis on a small scale. The result of mitosis is two identical cells, also referred to as “daughter cells” (Britannica, T. Editors of Encyclopaedia, 2024). It is a simple crucial process of growth that all cells must go through. 

A cell spends most of its life in interphase which includes growth phases that are not mitosis. There is the G1 phase which is growth in the cell, the S stage which is DNA replication and then the G2 stage DNA coils and organelles and “equipment” needed for mitosis are prepared (Sandra Alters & Brian Alters, 2006).

After interphase, prophase begins. Prophase is the phase where all DNA is coiled and condensed into chromosomes. The DNA is condensed and packed up into chromosomes so that none of it will get lost during the process of division. It can be thought of as packing up boxes when someone is moving so that nothing will get lost in the process. During prophase, the nucleus, nucleolus, and nuclear membrane all dissolve. This happens so that the cell will be able to begin metaphase, the next stage of mitosis (Britannica, T. Editors of Encyclopaedia 2023).

 Metaphase is crucial to cell division because this phase begins the lining up of the chromosomes. In the middle of the cell, chromosomes line up to then be pulled apart during anaphase. The mitotic spindle is what is used to pull apart the chromatids (Petruzzello, 2023). The chromatids are created during the DNA replication. Chromatids consist of a short arm, a long arm, and a centromere that connects the two (Rogers, 2023).

Anaphase happens directly after metaphase. Anaphase is the stage where the chromatids split apart in the middle of the cell. The chromatids are pulled to opposite ends of the cell by the mitotic spindle. This is an important phase of mitosis because it is used to ensure the chromatids are split on to each side evenly. In addition, the cell becomes larger and starts to pinch inwards preparing for the division (Britannica, T. Editors of Encyclopaedia 2023).

Telophase is the next stage of mitosis. This stage is when the chromosomes begin to uncoil back into long strands (noodle like) of DNA. The nucleus, nucleolus, and nuclear membrane all began to reform. The chromosomes begin to uncoil inside of the nucleus so that they do not get lost in the cell. The cell also pinches inwards more and begins separation (Petruzzello, 2023). This leads up to the last stage: cytokinesis. Cytokinesis is the separation of the cell into two identical cells (Britannica, T. Editors of Encyclopaedia 2019).

Bibliography

Alters, S., & Alters, B. (2006). Chapter 12: Cell reproduction. In Biology: Understanding life (pp. 182-183). John Wiley & Sons.

Britannica, T. Editors of Encyclopaedia (2024, May 6). mitosis. Encyclopedia Britannica. https://www.britannica.com/science/mitosis

Britannica, T. Editors of Encyclopaedia (2023, March 17). prophase. Encyclopedia Britannica. https://www.britannica.com/science/prophase

Britannica, T. Editors of Encyclopaedia (2023, March 24). anaphase. Encyclopedia Britannica. https://www.britannica.com/science/anaphase

Britannica, T. Editors of Encyclopaedia (2019, October 1). cytokinesis. Encyclopedia Britannica. https://www.britannica.com/science/cytokinesis

Petruzzello, M. (2023, March 17). metaphase. Encyclopedia Britannica. 

https://www.britannica.com/science/metaphase

Petruzzello, M. (2023, March 23). telophase. Encyclopedia Britannica. https://www.britannica.com/science/telophase

Rogers, K. (2023, February 15). chromatid. Encyclopedia Britannica. https://www.britannica.com/science/chromatid

Stingray Parthenogenesis

A North Carolina aquarium is home to the most remarkable stingray in the world. An adult female stingray called Charlotte is pregnant with four pups - without a male stingray to mate with in sight. At first it appeared Charlotte had a tumor, but on the eighth of February, scientists confirmed she was pregnant. According to the scientists managing the aquarium, she has not shared a tank with a male member of her species in at least eight years. There was speculation that she mated with one of the five sharks in her tank, but experts easily refute this theory because species cannot produce hybrid offspring with a species not closely related. The immaculate conception of Charlotte is rather a result of a phenomenon known as parthenogenesis, a form of asexual reproduction during which offspring develops from unfertilized eggs without genetic contribution by a male. These kinds of pregnancies happen most often in human care.

During the process of parthenogenesis, a female egg typically fuses with another cell known as a polar body and triggers cell division and the creation of an embryo. Parthenogenesis is a form of automixis; during an alternative form of this process, an egg cell will replace, reorganize and separate, while the polar bodies act as sperm and fertilize the egg. Dr. Dan Dombrowski, chief veterinarian at the North Carolina Museum of Natural Sciences in Raleigh, calls parthenogenesis a "stress response, or a way to save genetic material." It is known to occur in some insects, fish, birds and reptiles, such as California condors, Komodo dragons and yellow-bellied water snakes. 

Finley, B. (2024, February 14). Charlotte, a stingray with no male companion, is

     pregnant in her mountain aquarium. Phys.org. Retrieved April 5, 2024, from

     https://phys.org/news/2024-02-charlotte-stingray-male-companion-pregnant.html

Izlar, R. (2024, February 20). How a Stingray Likely Got Pregnant on Her Own.

     PBS North Carolina. Retrieved April 5, 2024, from https://www.pbsnc.org/

     blogs/science/how-a-stingray-likely-got-pregnant-on-her-own/

Human Body Systems

The human body is a single structure but comprises billions of smaller structures, including systems, organs, and cells. Systems are organizations of varying numbers and kinds of organs and different types of cells arranged together to perform complex functions for the body. Homeostasis is the state of balance among all of the body systems needed for the body to survive and function correctly. The survival of the human body depends on maintaining homeostasis of its internal environment and having all of the processes in the body work together to support the individual’s well-being and life.

Each of the major systems in the body is essential to the survival of the human organism, and each serves as a critical companion to the others. The nervous and endocrine systems direct the action and function of the body. The digestive, respiratory, and circulatory systems work together to supply oxygen and blood to tissue, remove waste, and break down, utilize, and absorb nutrients. The circulatory system carries crucial nutrients to the skeletal and muscular systems. The muscle and skeletal system collectively act to move the body based on the directions from the nervous system. The skeletal system also protectively houses internal organs, such as the brain, heart, and lungs while the muscle system aids in any body movement ranging from breathing muscles to 1-millimeter muscular structures. The skeletal system also interacts with the nervous system to coordinate sensory and muscle responses. When one of these systems is not functioning properly, one is guaranteed to feel this imbalance throughout the other systems within the body. The natural history of aging is that at some point in an individual’s life, one or more of the homeostasis processes is affected, leading to more or less significant unfavorable changes and ultimately death.

References

SEER Training Modules, Intro to the Human Body. U. S. National Institutes of Health, National Cancer Institute. 11 April 2024 <https://training.seer.cancer.gov/>.

Niemchick, A. and Rogers, . Kara (2023, November 29). human body systems. Encyclopedia Britannica. https://www.britannica.com/topic/human-body-systems-2237111