It's been several years since we last studied the human body in science class, however, I can still remember several things about the human body. The body is entirely composed of cells, which have been the basis of study for much of this year and can be read about in depth in many posts of this blog. The outside of the body is covered by many layers of skin cells, which are resistant to water and can heal themselves if damaged. Underneath our skin, we have bones connected by mussels and tendons and cushioned by cartilage. These bones have marrow inside of them, and are made of calcium. Throughout our entire body runs a vital substance called blood. In the blood there are many small cells, included red blood cells, which carry oxygen to the rest of the body, and white blood cells which fight diseases and parasites in the body. The disease-fighting agents are part of the lymphatic system. This system runs a substance called lymph through the entire body, which fights diseases and is filtered in certain places called lymph nodes. Blood can have four major types: O, A, B or AB. These types are determined by the presence or absence of certain antigens. Blood can also be RH positive or RH negative. Blood types are determined by genetics. The red blood cells receive oxygen in the lungs. In the lungs the oxygen diffuses into the cell. The blood is pumped by the heart, which has four chambers. These chambers come in two types, atrium or ventricle. Blood is brought in or out of the heart by veins or arteries. The brain controls the body, is sends signals to various body parts, telling them how to behave and complete their functions. The brain can be damaged in various ways, and yet it can also survive the most extraordinary circumstances. There is the remarkable case of Phineas Gage, who was stabbed in the brain. A metal rod went entirely through his head. His frontal lobe was destroyed, and even though his personality was changed he still lived for a remarkable twelve years before dying from seizures. The brain is a remarkable part of the human body, which is remarkably unknown.
The brain also controls the system which allows us to feel pain. This is done by nerves, which run throughout our bodies. They send signals to our brain, which make us feel pain. I know that when we eat food it travels down our esophagus into our stomach and through our intestines, where the food is broken down and nutrients are removed. This is the majority of what I know about the human body.
For a human being to function well, it is imperative that they remain healthy. This is the role of the immune system: to keep a body functioning smoothly. One key component of the immune system is the lymphatic system. The lymphatic system is made up of vessels that carry a substance called lymph. They lymph is cycled around the body, and remove bacteria, viruses, and rouge cells. It travels trough various areas that contain lymphatic tissue such as: the tonsils, the thymis gland, the spleen, and the bone marrow. It also travels through many small pockets of lymph tissue around the body called "lymph nodes". The purpose of the lymph nodes is to filter the lymph, which has picked up large amounts of foreign substances in the body. This is all very well and good, as long as the system works. It can be interrupted by several factors, some as simple as infections, which make the lymph nodes swell up. One of the most serious disturbances to the lymphatic system is a type of cancer called lymphoma. It is the seventh most common cancer in adults and the third most common cancer in children.
Lymphoma affects the lymphocytes found in the lymph. These lymphocytes identify any foreign cells, bacteria, viruses, and mutated cells. There are two different types of lymphocytes: B cells and T cells. B lymphocytes create antibodies which alert other cells, such as white blood cells, to the presence of pathogens so that the pathogens can be destroyed. T cells can kill pathogens without any outside help, and also assist in regulating the immune system. Once they have encountered a pathogen initially they will recognize it upon any further encounters. This is a key component in the way vaccines work. When a vaccine is injected into a person, the lymphocytes recognize the strain of the bacteria or virus and will attack it in the future.
A lymphoma occurs when either the B or T cells grow and multiply rapidly. The cells will continue to multiply, forming a large mass called a tumor. This tumor prevents the areas around it from having enough resources to function normally. Lymphomas are also able to metastasize and spread across the body very rapidly via the channels that make up the lymphatic system. Lymphomas are separated into two different categories: Hodgkin's Lymphoma (referred to as HL) and non-Hodgkin's Lymphoma (referred to as NHL). As of 2010, 628,415 people had lymphoma or were in remission. 153535 of these cases were HL and 474880 were NHL.
The first known example of Hodgkins. lymphoma was found in 1666, by Malpighi. In his paper De viscerum structuru exercitatio anatomica, he describes the disease that would later be referred to as "Hodgkin's lymphoma" or "Hodgkin's disease". Almost 200 years later, in 1832, Hodgkin publishes his own paper on the lymphoma, and thus the affliction was named after him. Research into "Hodgkin's disease" continued for many years afterwards, and in 1898 Cal Sternberg, a German researcher, discovers the Reed-Sternberg cells present in Hodgkin's lymphoma. Four years later, in 1902, Dorothy Reed, working at the Johns Hopkins Hopital in the United States, discovered the Reed-Sternberg cell on his own. From that point on scientists devoted time and energy into finding a cure of this disease
An image of a lymphoma
Hodgkin's lymphoma is given a separate classification because it occurs from one specific abnormality in the B cells alone. The tumors also contain Reed-Sternberg cells, named for the scientists who initially discovered the cell. Hodgkin's lymphoma will typically start in the area around the neck. It will then spread downward through the nodes to the rest of the body. If the cancer manages to spread below a person's diaphragm it will infect the spleen and therefore infect both the liver and the bone marrow. The cancer will also begin in the chest occasionally. From there it will spread to the areas around the heart and the lungs. There are five different types of Hodgkin's Lymphoma: Nodular Sclerosing Hodgkin Lymphoma (NSHL), Mixed Cellularity Hodgkin Lymphoma (MCHL), Lympocyte Depleted Hodgkin Lymphoma (LDHL), Lymphocyte-rich Classic Hodgkin Lymphoma (LRCHL), and Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL).There are four different stages of HL. Stage I is the infection of one singular lymph node region. Stage II affects two lymph node areas on the same side of the diaphragm (either waist up or waist down). Stage III has lymph nodes affected on both sides of the diaphragm (both waist up and waist down). Stage IV indicates that the cancer has spread outside of the lymph nodes. The cause of Hodgkin's lymphoma is currently unknown, but there are many risk factors that can lead the the development of a tumor. Primarily, it is believed that immune suppressive diseases increase a person's risk of developing the disease. These include: having had mononucleosis as a young adult, having suffered from human T-cell lymphoctyotropic virus (a virus that affects the lymphatic system, also called HTLV), having contracted HIV, being infected with Hepatitis B or C, having herediaty diseases that affect the immune system (severe combined immunodefience, ataxia telangiectasia), having received immune suppressive therapy, exposure to toxic chemicals, or having a family history of lymphoma.
Non-Hodkgin lymphoma was first differentated from Hodgkin's lymphoma by Henry Rappaport in the years 1956 tp 1966, which led to the Rappaport classification, the first classification of Non-Hodgkin lymphoma. The classification "Non-Hodgkin's lymphoma" refers to any type of lymphoma without the Reed-Sternberg cells, which can affect both the B cells and the T cells and has a variety of genetic markers. There is a one in fifty chance that a person will develop non-Hodgkin's lymphoma at some point in their life, although the affliction is more common in men. There are thirty different types of non-Hodgkin's lymphoma, which fall into three different classifications. These are classifications are Indolent (slow-growing, low grade), Moderately aggressive (intermediate grade), and aggressive (high grade). These are differentiated by how quickly the cancers are spreading, with low grade as the slowest spreading and high grade as the fastest spreading. As with HL, the cause of NHL is unknown. However, scientists and researchers have linked the disease to "immune suppression". Immune suppression is when a person has had a disease which has impacted their immune system to a point at which it does not function properly. Some examples of these diseases would be HIV, HTLV, Hepatitis B or C, hereditary diseases that affect the immune system (severe combined immunodeficience, and ataxia telaniectasia) and mononucleoisis. Additionally, having contact the bacterium Heliobacter pylori can also increase the likelihood of developing a lymphoma (and has also been linked to stomach cancer). An interesting factor that can increase the chance of a person having a lymphoma is living in a faming community. Doctors believe that the use of pesticides and herbicides may be the reason, because they contain certain chemicals. These chemicals may also be found in black hair dye, the use of which has been linked to NHL. As with HL, a family history of lymphoma is also a factor.
Both HL and NHL have very similar symptoms. The most common of these are: swelling of the lymph nodes, fever, unexplained weight loss, sweating, chills, lack of energy, itching, rashes, lower back pain, and sore lymph nodes after drinking alcohol. Unfortunately, the symptoms vary greatly between cases, and are often misdiagnosed as the common cold or the flu.
There are three different treatments used on both HL and NHL. These are radiation therapy, chemo therapy, and biological therapy (or immunotherapy). Radiation therapy employs high-energy rays (radiation) to kill the cancerous cells. This is used on specific areas of the body, rather than the entire body. Chemotherapy uses powerful drugs to kill cancer cells. These are administered intravenously, then circulate trough the bloodstream impacting the entire body. Biological therapy is a relatively new type of therapy, which essentially trains the body to remove the cancerous cells on its own. There are three different types of biological therapy used to treat cancers. The first us Monoclonal anitbodies. A monoclonal antibody is an anibody that is made in a lab instead of in the body. They are designed to attack a certain pathogen. They are used by the immune system to kill tumor cells and or can bring raditation or chemotherapy directly to an “antigen”. The second is Cytokines. They are naturally in the human body, but can also be created in a lab. They are then brought into the body to assist in the finding of cancers. The third is a cancer vaccine. These vaccines do not prevent a cancer from developing, instead they allow the immune system to recognize cancerous cells and destroy them. After Hodgkin's Lympoma has been treated, patients typically make a strong recovery. Similarly, 30-60% of patients with aggressive non-Hodgkin's Lymphoma can be cured. However, there is currently no cure for indolent NHL, although patients typically live up to twenty years after the cancer has been diagnosed. Even after being treated, people who have had HL can have complications such as infertility, liver failure, lung problems, and the development of other cancers. People who have had NHL and are in remission can become Autoimmune hemolytic anemic and develop other infections.
In conclusion, there are a wide variety of lymphomas. They can be fatal if ignored, and are often mistaken for the common cold. However, when they are found they are usually treatable, and if we continue to focus our efforts on innovative treatments, such as immunotherapy, this cancer could be cured.
