All of the Many (Actually Few) Things I Know About the Human Body

Now that I'm thinking about it, the human body is an amazing thing.  There is so much that it can do as long as it is taken care of.  It can digest food, breath in air and convert it to carbon dioxide, pump blood, lift things, smell things, touch things, see things, and most importantly think.  The coolest part about the human body is the brain and what it can do.  The brain can think anything that it wants to and develop many ideas.  If not for my brain, I would even be able to write this blog post or, for that matter, recall anything that I know about the human body.  Unfortunately, I don't know much about how the brain works, or any other part of the human body.  What I do know though is that the body is made up of many systems.  Each system has a different function and exists to accomplish a specific and unique task.  There are so many systems because there are so many things that we rely on our body to do for us.  Some of the systems I can think of are the nervous system, circulatory system, digestive system, respiratory system, immune system, muscular system, urinary system, and bone system.  I also know that there are some things a body needs to function.  One important thing is exercise.  I'm not exactly sure why this is important but I know it plays a significant role in keeping the human body running smoothly.  Other things include food, oxygen, vitamins, and energy.  I am pretty sure that the vitamins and energy often come from the food but can be acquired in other ways too.  For instance, I think that the body can take in some vitamins from the sun.  Regardless, the process of taking in food and processing it to take advantage of it occurs in the digestive system.  The purpose of the respiratory system is to take in air and use the oxygen in it for the body and produce carbon dioxide.  The urinary system's purpose is to remove waste products from the body.  The muscular system allows the body to move and do strenuous activities.  The immune system protects the body from disease and the circulatory system spreads oxygen in the blood throughout the body to all the other parts and systems.  The nervous system is what recognizes different senses and sends messages to the brain.  Each system can be made up of multiple parts of the body. For instance, the digestive system includes the stomach, large and small intestines, liver and maybe even some others.  There is also the reproductive system which lets the body produce offspring.  Each system contributes to the body in different ways but together they allow it to function as it does.

Photo Links:
http://www.joy2day.com/health/wp-content/uploads/2010/09/body-system.jpg
http://www.human-nervous-system.com/wp-content/uploads/2009/07/human-nervous-system.png

Can you roll your tongue? Well, that's genetics.

Over the past few days we've learned a whole lot about genetics.  We figured out that specific traits that one possesses are not a cross between the traits of his or her parents or just random but actually determined by the combination of genes and alleles.  There are two kinds of alleles: dominant and recessive.  Two dominant alleles paired together is called a homozygous dominant pair and this will obviously express the dominant trait.  A dominant allele paired with a recessive allele also known as a heterozygous pair will express the dominant gene or trait but still carry the recessive trait so that it may be expressed in future generations.  The only way for a recessive gene to be expressed is when there is a homozygous recessive pair or a pair of two recessive alleles.  We did several different tests both in class and at home to see which traits different people possess and, based on their parents traits, what their genotype is for that trait or what is the allele pair that they have.  Weather one possesses a certain trait or not and which kind of trait it may be is known as his or her phenotype. Below is a chart that shows the different phenotypes and genotypes of me and my family.

 Based on the phenotypes for each trait of each of my family members, I was able to determine their genotype for each trait because each allele pair is one of the alleles from your mother's pair for that trait and one from your father's pair for that trait.  Based on the different combinations possible for my brother and I from my mother and father's allele pairs, I could tell what genotypes we have.  For some of the traits however, I was not able to figure out the genotypes because for dominant traits that are present or recessive traits that are not present there are two options for allele pairs and the trait in my parents did not help me figure out which pair each person had for these traits.  I also decided to test for thumb crossing when one intertwines their fingers.  This is a trait that I learned was genetic on the internet and decided to see which thumb each family member puts on top when they intertwine their fingers.  I got the results similar to my Hitch-Hiker thumb results with my mom and I going left over right and my father and brother vice versa.  This means that my mother and I are heterozygous for this trait while my father and brother are homozygous recessive because left over right is a dominant trait.  I think it is really cool how you can figure out ones genotype based on the phenotypes of them and their family and how traits are passed down through Mendelian genetics.

GGGGENE TESTING!

Genetic testing is a biological subject of constant research and innovation.  A relatively new procedure, genetic testing is when scientist can test one’s genes to determine the likelihood of the person getting certain genetic disorders by directly examining the strands of DNA for mutations in the sequence.  Any sort of sample can be used including, tissue, blood and hair.  The method of this examination is fairly complex and there are several different ways such genetic testing is preformed.  Sometimes, scientists use probes, which are short strands of DNA complementary to certain mutated strands that can lead to certain disorders and diseases.  Once placed in the body, these probes will find and flag any complementary mutated DNA strands if they are present in the human genome.  This means that using probes in gene testing only tests for specific disorders and diseases.  Another method of testing includes determining the DNA based on enzymes and other proteins because the nucleotide sequence of DNA determines the primary structure of all proteins.  This can tell scientists what DNA a person has and alert them of any mutations.  Gene testing can often lead to gene therapy where mutated DNA strands are altered and corrected in order to prevent certain diseases and disorders.  Currently there are over one thousand gene tests that can be preformed, each to test for the risk of a different condition.  Under the Genetic Information Nondiscrimination Act, no health care or insurance can discriminate against someone who has received gene testing.

            Gene testing can do many things for a person.  First of all, as previously mentioned, its main purpose is to determine whether someone will contract certain diseases.  Gene tests can also be used to identify if someone is carrying a certain  disease in one gene but they won't be affected because they are lacking a second gene that would cause them to contract this disease.  This is important because it lets someone know about any recessive disease genes a person has that could get passed down to their children.  If two people, each with a recessive gene that causes the same disease, had a child, this child will have a high risk of contracting the disease.  Gene testing can be used on newborns to alert parents of diseases the child might contract later in life.  It is often used to test people for adult disorders, cancers, and alzheimers before the patient has symptoms.    The genes of an embryo in-vitro can even be tested after fertilization to check for gene abnormalities that could lead to extreme diseases, disorders and mental handicaps.  This can allow parents to avoid having the child through an abortion so that it will not have to face extreme conditions in its lifetime.  When gene testing does show disease in ones future, doctors can often help the patient perform preventative measures.   Testing is also a way to confirm diagnosis and can also help determine specific treatment methods.

In the future, gene testing could make diseases that are fatal once contracted into completely treatable conditions and maybe even curable.  Research is currently being done with a common iron storage disease.  Even now, gene testing can save lives.  The constont monitoring of colon growth in people with familial adenomatous polyposis genes found during gene tests can prevent people from dying.

There are, however, several issues with gene testing.  For one, tests for disorders can sometimes be limited because they only provide a probability of contraction of disease.  The tests might give a high probability but people still sometimes never contract the conditions.  Gene mutation is also not the only thing that causes these conditions and combinations of genes and environmental factors often play an important role.  These tests are also sometimes considered immoral because of the anxiety they can create when high risk is determined.  Sometimes it is just better to know about a disease when you contract it, especially if there are no real forms of treatment and no cure.

In a recent genetic testing study scientists determined that it is possible to test genes in fluid and tissue samples around the fetus for mutations that lead to down syndrome in the child.  This new method is safer, cheaper, and faster and can lead to the decision of abortion so that the parents will not have a child that suffers from down syndrome.  The reliability of this new test is still being confirmed but it should be in use within two years.  Genetic testing is also helping those who contract scoliosis.  Although this disease is incurable, personal gene tests can determine specific treatment for each case and allow patients to begin treatment before the effects of scoliosis begin.  These are some of the ways that gene testing is helping people in different ways each day.

http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetest.shtml

http://www.myhealthnewsdaily.com/down-syndrome-fetal-test-maternal-blood-1241/

http://www.einnews.com/247pr/199858

Laron Syndrome - Imunity to Cancer?

I found this article about Ecuadorians with Laron Syndrome really fascinating.  It talks about how those with this syndrome have stunted growth but at the same time, the genes that cause the syndrome give these people immunity to cancer and diabetes.  This was first discovered by a scientist studying one hundred or so Ecuadorians with this condition who noticed that not one of them had ever had cancer or diabetes although the area where they all lived had high numbers of cancer and diabetes victims.  After some studies he finally learned why this was happening.  He soon discovered also that this condition first originated in Ecuador when some European carried it over many years ago.  I am amazed by all of this and the first thing that came to mind after reading this was if somehow people who don’t have the syndrome could use these genes to prevent cancer and diabetes.  This syndrome happens when there is a mutation in a certain gene that codes for growth hormone receptor and eventually produces lower amounts of IGF1, a growth factor. Because high levels of IGF1 can lead to cancer and diabetes, these low levels result in immunity.  I think it would be so great if we could cause this mutation in the gene in all humans so that everybody could be immune to these diseases.  All it takes is some research to see how this gene mutates and if it would be possible to simulate this mutation in those without the syndrome or if there is another way to decrease the levels of IGF1 while at the same time not resulting in stunted growth.  Specifically, there is a case of a young Ecuadorian that has Larons while her sisters do not even though they carry the same gene. It sounds like it is really difficult to figure out about how this could lead to prevention of cancer and diabetes, but if such a discovery is made, so many lives would be saved.   Tests and experiments should be made very carefully though because based on this article, it sounds like badly done tests could be very harmful to the body.  Tests are already being carried out in mice to test the effects of this condition and lack of IGF1.  In the future, drugs that cause this mutation of the gene could become common and lead to at least major prevention if not a cure.

http://abcnews.go.com/video/playerIndex?id=6303784

Cancer Cells of the Stomach

There are many types of cancer but one of the most horrible kinds is stomach cancer also known as gastric cancer. It is the fourth most common cancer in the world with 21,000 new cases in 2010 and 10,570 deaths according to the National Cancer Institute. It is most common in people in their sixties and seventies and is much more commonly found in men than women with approximately 13,000 men diagnosed in 2010 and 8000 women. Once diagnosed, 26% of people will survive the next five years if the cancer has already spread in the process of metastasis as most often the case is and 63% will survive if it is caught before metastasis has occurred. Thankfully, mortality rates are slowly decreasing across the world with developments in medicines and treatments everywhere.

There are five main types of gastric cancer. The most common of the five is gastric adenocarcinoma, which is the kind in 90% to 95% of stomach cancer cases. It occurs in glandular tissues around the stomach. Intestinal Adenocarcinoma is in tissues near the intestines and most common in those over 80 while diffuse adenocarcinoma is more likely to found in younger patients with blood type A. The remaining four types of stomach cancer are all much more rare. Gastrointestinal lymphoma is found in the immune system tissue of the stomach wall. Gastrointestinal leomysarcoma happens in the muscle layer of the stomach and often doesn’t spread to the lymph nodes. On the other hand, Gastrointestinal Stomal Tumors form in tissues that support the digestive organs when intestinal cells of Cajal are present. The last type, gastrointestinal carcinoid tumors, forms in the stomach tissues that produce hormones and this kind rarely metastizes and spread.

Stomach cancer is often unavoidable but there are some things that can encourage cancerous cell growth and some preventative measures that can be taken although not extremely effective. Smoking has been shown to be linked to gastric cancer and because of this, avoiding smoking is one of the preventative measures that can be taken. Lots of salt and not enough fruits and vegetables also increases the risk so it is good to stay away from salty foods and eat lots of fruits and vegetables because vitamin C is known to decrease the risk. A major cause of gastric cancer is the bacteria Helicobacter pylori (H. pylori), which can grow in the stomach and lead to the growth of cancerous cells. These bacteria are able to remain in the stomach often unnoticed. Although it doesn’t always lead to a case of stomach cancer, this is a very important and common risk factor.

The biggest cause of stomach cancer is genetic. Stomach cancer is largely hereditary meaning that it comes from genes passed down from parent to child. The mutations of these gene’s can lead to the uncontrollable growth of cancer cells in the stomach. Specifically, there are three main genes that can cause gastric cancer. CDH1, a gene that produces proteins that allow cells to adhere to each other and form tissues, acts as a tumor suppressor (a gene that checks to make sure that no problems occurred in the cell cycle and cell division). When this gene mutates, it doesn’t do its job of checking for problems, which can lead to continuous production of cancerous cells without being stopped. Another tumor suppressor gene, TP53, can cause gastric cancer for the same reason when it has mutated, is inactive, or is absent from the area. This happens in 80% of stomach cancer patients. The mutation of APC, a third tumor suppressor gene that also acts as a cell signaler, leads to gastric cancer as well. It mutates in only 25% of gastric adenocarcinoma cases but can mutate in as often as 60% of intestinal stomach cancers.

Another thing that can end up leading to cancer is cyclins. A cyclin is a protein that activates enzymes known as kinases. Kinases then tell a cell to continue on in the cell cycle and divide. Cyclin E in particular is sometimes overexpressed by 20% to 30% and this can lead to the constant production of cancerous cells. When this cyclin activates many kinases and they tell the cells to keep on dividing without stopping, then cancerous stomach tumors grow.

Once someone has a stomach cancer tumor growing inside them, there are several different symptoms that can identify it. They include pains and discomfort in the stomach, nausea and vomiting, swallowing difficulties, weight loss, feeling full even after eating a small meal, vomiting blood, and having bloody stool. These symptoms are not definitive however because they can be found as signs of other diseases as well. This means that if such symptoms are identified, the patient should see a doctor before drawing any conclusions.

In order to diagnose someone with stomach cancer, a gastroenterologist may use several methods. First of all he might feel the abdomen for any abnormalities including swollenness of the lymph nodes. He also might perform an endoscopy where a camera is sent through the mouth and numb esophagus to look inside the stomach for any tumors. A biopsy might also be preformed in which the doctor would use an attachment of the endoscope to remove some tissue. This tissue sample could then be examined for cancer cells.

If the gastroenterologist determines that a patient truly does have stomach cancer, the tumor and cancerous cells must be staged. The purpose of this staging is to determine the best treatment for the patient. The stage of a cancerous tumor is based off of several factors, mainly the tumor itself, the lymph nodes around it, and the amount of metastasis that has taken place. A combination of all these factors determines which stage the cancer is in. Diagnosis tests show the state of each of these factors and help doctors stage the cancer.

The most common method of treatment for stomach cancer at an early stage is surgery. This always involves removal of the tumor. A gastrectomy not only removes the tumor but also the entire stomach. Partial or subtotal gastrectomys are also preformed and this is where only part of the stomach is removed. A third type of surgery that can be used to treat stomach cancer is a resection where the specific tumor is removed along with the surrounding tissues. Each of these methods also normally removes the lymph nodes around the tumor. When such surgery is preformed, the doctors always check back to make sure that the entire tumor was removed and no cancerous cells were left in the body.

Another way that gastric cancer can be treated is using radiation. This is when radiation waves are sent into the body to damage and kill cancer cells. This form of treatment involves repeated radiation sessions and doses for months. The kind of radiation used for stomach cancer is known as external radiation in which a machine directs radiation to the cancerous cells and tumor in the body using a ray. This ray is very direct and specifically pointed so as not to effect places uninhabited by cancerous cells. Radiation doesn’t usually kill noncancerous cells although sometimes it can but all efforts are made to direct it only at cancerous tumors. There unfortunately can be side effects to radiation.

A final method of treatment for gastric cancer is chemotherapy. Medicine and drugs are given to the patient to kill the cancer cells as they divide. They do this by interfering with DNA replication, messing up the spindle fibers that pull apart chromosomes, and damaging DNA. This, as with radiation can have an effect on noncancerous cells but, in the same way, rarely does.

As shown, gastric cancer is a horrible form of constantly dividing cells that form tumors and strongly affects tens of thousands of human beings each year. Although there is not yet a cure for this form of cancer, scientists are working hard to protect and save the lives of those with stomach cancer.

Stomach (Gastric) Cancer

• http://www.cancer.gov/cancertopics/wyntk/stomach
• http://www.cancer.net/patient/Cancer+Types/Stomach+Cancer?sectionTitle=Overview
• http://www.cancer.gov/cancertopics/pdq/prevention/gastric/HealthProfessional/page2
• http://www.omnimedicalsearch.com/conditions-diseases/stomach-cancer-types.html
• http://www.cancerquest.org/gastric-cancer-introduction
• http://www.cancerquest.org/cancer-treatment-surgery
• http://www.cancerquest.org/demo/ACS/RT/RadiationTherapy_V2.swf
• http://www.cancerquest.org/chemotherapy-introduction
• http://www.cancer.gov/cancertopics/factsheet/Risk/h-pylori-cancer
• http://www.biology-online.org/articles/cellular_molecular_aspects_gastric/molecular_mechanisms_gastric_carcinogenesis.html

That Amazing Process We Call Photosynthesis!

This week we have been learning about an amazing process that goes on in plant cells known as photosynthesis.  This process uses the suns energy to make energy for the plant.  In general terms, what happens in photosynthesis begins with the chlorophyll in chloroplasts in a plant cell absorbing the suns rays or photons.  Then they convert the light energy into chemical energy which they can store as sugars at the end of this process.  There are two parts to achieving this.  They are the light reactions and the Calvin cycle which is light independent.  One of the amazing things about this process is that it is, as far as I know the only one that can oxidize water molecules into their electron, proton and oxygen.  Oxygen is also released when CO2 is oxidized for the use of the carbons.  This oxygen can then be used for our breathing needs.  Another astonishing thing about photosynthesis is the rates at which it happens.  You can learn more about how the two steps in photosynthesis work in this jing video about photosynthesis!



There are somethings however that i think might effect the rates of photosynthesis.  I think that the temperature of the area around the plant might have some effect on it and that plants in different climates might go through photosynthesis more or less. I also believe that the strength of the sunlight would as well as in how intense the sunlight is and whether its coming through clouds or not.