Endocrine Disruptors

            There are a number of compounds that can obstruct endocrine system pathways and cause harmful effects on the human body. These chemicals are known as endocrine disruptors, substances that may mimic or interfere with the function of hormones in the body. These compounds are also known as “endocrine modulators, environmental hormones and endocrine active compounds.” We are unknowingly exposed to these compounds in our daily life in the form of plastic products, makeup, canned food, detergent and pesticides/herbicides.

Endocrine disruptors work by three different mechanisms. They can imitate endocrine hormones (thyroid and sex hormone) and trigger their effects. Endocrine disruptors attach to receptors inside the target cells and obstruct the naturally occurring hormones from attaching. In this way, the signal is not produced and the body is not able to react correctly. Endocrine disruptors also can obstruct or control the pathway by which endocrine hormones are made. They affect at low concentrations and cause a variety of diseases. Some studies show that they decrease fertility and increase progression of diseases.

People are exposed to endocrine disruptors through the mouth, skin and respiratory tract. Some of these chemical such as dioxins, DDT and polychlorinated biphenyls are extremely persistent and decompose gradually. They are broadly distributed in our surroundings. Kids are at a higher risk from exposure to endocrine disruptors because they are generally more susceptible than adults. The endocrine system is responsible for development of body and it is adversely affected by the disruptor. To decrease the hazard from disruptors we can take some precautions from our side, such as reduce use of pesticides, use organic foods, do not use plastic containers or wraps to store foods, and do not provide your child with soft plastics toys etc.

Work Cited :

(1) http://www.niehs.nih.gov/health/materials/index.cfm (endocrine – endocrine disruptors.pdf) (2) http://www.nrdc.org/health/effects/qendoc.asp

Arial Donnell

Alzheimer’s disease is an irreversible, progressive brain disease that slowly destroys memory and thinking skills, and eventually even the ability to carry out the simplest tasks. There are three stages to the disease, mild, moderate, and severe. Currently there isn’t any cure for the disease and symptoms tend to worsen as the years progress and the individual moves into the later stages.

During a study, researchers used mouse models to test a protein, amyloid beta, to see how the loss of smell occurs in the brain. They found a tiny amount of amyloid beta causes smell loss in mouse models. In the beginning, the olfactory bulb, which receives input about odors detected by the nasal cavity, became hyperactive. Over years, amyloid beta increased inside the bulb and the more hypoactive the bulb became. Despite the longer period of sniffing, the mice were unable to remember smells and incapable of differentiating between odors. Same as in humans, as mice age they lose their sense of smell. To show a reverse of effects, researches then gave the mouse a synthetic liver x-receptor agonist, which is a drug that clears the protein, amyloid beta, from the brain. The mice were able to distinguish different smells again within two weeks. However, after one week of withdrawal, symptoms returned yet again.

Alzheimer’s disease not only affects the individual, but it also affects every person who plays a role in that individual’s life. With the findings and discovery, hopefully a cure for the disease will soon be made available. A cure will be greatly needed since studies show by 2050 Alzheimer’s disease is expected to triple to 16 million.

(1.) “Alzheimer’s Disease Fact Sheet.” National Institute on Aging. U.S. Department of Health and Human Services, n.d. Web. 13 July 2013.

(2.) Case Western Reserve University. “Early sign of Alzheimer’s reversed in lab.” ScienceDaily, 1 Dec. 2011. Web. 12 Jul. 2013.

Childhood Obesity and Taste Buds

Taste is something that most people don’t even think about experiencing in daily life other than after a delicious meal or, inversely, a terrible meal.  However, it is a complex system that is accomplished through the use of taste buds.  These taste buds allow us to taste five primary flavors: sweet, bitter, salty, sour, and umami, with umami tasting like meat.  Although we can taste all of these flavors, we have a higher sensitivity to sour and bitter substances likely due to survival needs.

The experiments conducted on the almost 200 children, with a little over half being obese, were tasting tests that determined whether a child could differentiate between the five flavors and explain the intensity at which a flavor was administered.  The study found that obese children, when compared to normal weight children, would have difficulties distinguishing between both intensities and certain flavors.  These flavors were the salty, umami, and bitter tastes.  This study concluded that obese children have taste buds that are less sensitive than that of their normal weight counterparts.

As we begin to better understand childhood obesity, we can more easily attempt to stop it from happening.  Because we believe that these children have less sensitive taste buds and could be a contributing factor of the obesity, scientists could find a way to heighten the sensitivity of the taste buds.  Another solution could be to find foods with very high intensities to satisfy the cravings that these children have.  Ultimately, this will help the individual from suffering from conditions and diseases that the obese are prone to obtaining.

Tortora G.J. and B. Derrickson. 2012. Principles of Anatomy and Physiology. 13^th ed., John Wiley and Sons

BMJ-British Medical Journal (2012, September 19). Obese children have less sensitive taste-buds than those of normal weight. ScienceDaily. 12. Jul. 2013. Web.

Color Vision

In vision, color perception depends on wavelength. The photoreceptors that are involved in vision are rods and cones. Rods allow us to see dim light but don’t provide color vision in dim light so we only can see black, white, and shades of gray (Tortora & Derrickson). There normally about 120 million rods. Cones are stimulated by bright light which produces color vision. There are normally 6 million cones (Tortora & Derrickson). In essence, different people may see one subject in many different ways.

In a study on the evolution of color vision conducted at the Howard Hughes Medical Institute, researchers introduced a human gene into a mouse chromosome. The human gene code was for a light sensor that a mouse normally does not have (Nathans). The goal of th experiment was to see if a mouse’s brain was capable of using the human photoreceptor to see just as many colors as we can. The mice used in this study actually exceeded their expectations. They had to test the mice to see how well their color vision had developed so they showed them color panels. The mice chose the correct panels in 80 percent of the trials (Nathans). The study is what led them to the conclusion that the trichromatic color vision that we now enjoy came from distant ancestors of all primates. There are consequences of trichromacy as well. We perceive what we see on television and computer screens as a full spectrum of color when in reality the colors are just mixtures of red, green, and blue pixels. After reading this research, the evolution of color vision is clearly a complex process.

The study of the human eye is a task itself when there are so many different components that function around the eye. The retina can provide the most information when studying color vision. Maybe one day some researcher will be able to explain what all the human eye is capable of because without color vision everyone would only see black, white, and shades of gray. No one wants to live in a dim world.

Gerald J. Tortora and Bryan Derrickson. Principles of Anatomy and Physiology. 13^thed., John Wiley and Sons, 2012.

Nathans, Jeremy. “HHMI News: Genetic Studies Endow Mice with New Color Vision.”HHMI News: Genetic Studies Endow Mice with New Color Vision. Howard Hughes Medical Institute, 23 Mar. 2007. Web. 12 Feb. 2013. <http://www.hhmi.org/news/nathans20070323.html>.

LASIK surgery is an increasingly popular alternative to wearing glasses or contacts. It reshapes the cornea and changes the focusing power. The intent of the surgery is to correct the curvature of the cornea for conditions that include farsightedness, nearsightedness, and astigmatism (Tortora & Derrickson). Nearsightedness can be corrected by using a concave lens that diverges the light rays coming in so that they are in focus directly on the retina. In farsightedness, the correction is a convex lens that converges the light rays entering to focus directly on the retina (Tortora & Derrickson). After surgery, however, there could be side effects such as dry eyes and sensitivity to light.

There are many different studies being conducted involving the sensitivity of the cornea after the surgery takes place. In one particular scientific study, patients were examined to investigate whether LASIK surgery was the cause of patient’s cornea sensitivity and dry eyes. Twenty patients who had undergone myopic LASIK surgery two to five years previously were placed with ten people who had not received the surgery. The cornea sensitivity was assessed by using a non-contact esthesiometer. (PubMed)

The degree of dry eye symptoms was significantly higher in patients who had received the LASIK eye surgery treatment, rather than the patients in the control group. The majority of patients also reported ongoing symptoms, although the testing for that in particular was not conducted. (PudMed) Some claimed they had never had such symptoms until after the surgery.  It appears that the LASIK surgery could have played a role in the tear deficiency of the patients, as well as the sensitivity.

Works Cited:

Gerard J. Tortora and Bryan Derrickson. Principles of Anatomy and Physiology. 13^th ed., John Wiley and Sons, 2012.

Journal of Refractive Surgery from PudMed.gov 2007. <http://www.ncbi.nlm.nih.gov/pubmed/17455828>

The individual components of the eye work in unison, with each part playing a vital role in providing clear vision.  The cornea acts as the eye’s main focusing segment.  It takes a widely diverging ray of light and bends it through the pupil which is surrounded by the colored iris.  The eye is very complex, and with this complexity various problems can occur.  With new technology, doctors are able to restore many forms of impaired vision.

A new study completed in Kobe, Japan looked into the development of mammalian eyes from stem cells.  Yoshiki Sasai grew what is now known as an optic cup using human stem cells.  This breakthrough was encouraging due to the ability for Sasai to grow three-dimensional tissues unlike the two-deminsional sheets that were being developed.  Observing the optic cup, structural similarities were seen when compared to normal development of an human in vitro eye.  Sasai was impressed to notice that layers of the eye were grown in the same sequence without his aid.

This new achievement could aid scientists in a clinical setting aiding to the increased successes in transplanting stem cell photoreceptors into mice.  This transplant only offered rod receptors that would only give unclear images.  Sasai’s optic cup is being looked at to one day integrate both photoreceptor tissues into humans.

Yoshiki, Sasai, Eiraku Mototsugu, et al. “Self-organizing optic-cup morphogenesis in three-dimensional culture.” Nature. 472.7341 (2010): 51-56. Web. 28 Jan. 2013. <10.1038/nature09941 >.

Tortora, Gerard J., and Bryan Derrickson. Principles of Anatomy and Physiology. Hoboken, NJ: John Wiley & Sons, 2010. Print.

There are many reasons as to why people go blind. For example, blindness can occur because the lens of the eye became cloudy, which prevents light from entering the eye, or because the retina got degraded and deteriorated, which affects the perception of images (1). Another cause of blindness could be caused by a change in eye shape, which alters the projection of an image, or because of damage to the optic nerve, which disrupts the flow of visual information to the brain (1).  Blindness can also occur because of an eye injury or trauma (1). However, the leading cause of blindness in the United States is caused by eye diseases (1).

Because technology has advanced so much in the past few years, people with failing vision can now get a corneal transplant. However, now there is an even better solution to improving eye vision. The University of Tuebingen in Germany has developed a chip that can be implemented into the eye which transforms images into electrical impulses that are sent to the brain, which allows the person to see (2). The clinical trials for the chip implant were done on people who suffered from retinitis pigmentosa, a hereditary condition that destroys the retina (2). The results showed that out of the eleven people who received the surgery, five were able to see or distinguish objects (2).

Although this new chip implant discovery does not work a hundred percent, I believe it is only the beginning. With this new discovery, people who have suffered from blindness can now have the hope that they will be able to see once again. This new discovery will not only provide hope to the family of the victim, but it will also give the victim confidence and raise his or her self- esteem.  He or she will once again be able to live his or her life however he or she wishes. Furthermore, with technology improving every day, I am sure one day people will not have to suffer from blindness anymore.

1.)    Thompson, Dennis. “What Causes Blindness? .” EverydayHealth.com. (2010): n. page.      Web. 30 Jan. 2013.

2.)    Bukowski, Jack . “Let There Be Light: New Technology Enables Some Blind Patients to   See .” InsidersHealth.com. (2011): n. page. Web. 30 Jan. 2013.