Again, this is just a quick post. The main focus of these two questions appears to be simply defining some of the key terms when talking about cancer.
1. Why is the word potential important in defining the characteristics of invasion and metastases in cancerous tissue?
One of the characteristics of cancer is that it has the potential to invade and metastasise. Not all cancers invade or metastasise but the cancerous cells do need to have the ability to potentially break through the basement membrane of tissues to be considered cancer. Or something. It seems like a bit of a weird definition to me.
2. What is the difference between primary cancers and metastatic cancer?
This one is a bit easier to answer! Primary cancer is the first cancer that appears, while metastatic cancer refers to cancer that has spread around the body from its origin. For example, you can have breast cancer that metastasises to the ovaries. In this case, breast cancer is the primary cancer, while the cancer in the ovaries is metastatic.
Wednesday, July 1, 2015
The Immune System
The immune system is vastly complex but unfortunately my notes are rather limited. If you wish to learn more about the immune system you'll have to find your own resources for now until I take a microbiology and immunology in 2nd year and can share what I learn with you :P
1. How do natural killer cells differ from T-cells in their recognition of an enemy?
While natural killer cells and T-cells kill off invaders through a similar mechanism (contact followed by release of certain enzymes), they differ in their recognition of an enemy. T-cells have T-cell receptors that recognise particular antigens on the surface of invading cells and are thus relatively specific. Natural killer cells, on the other hand, simply look for whether or not an invader has a "self" marker on the cell surface, and can thus kill a wide variety of invaders. These markers are called major histocompatibility (MHC) antigens, and differ from person to person (except in the case of identical twins).
2. What cells are affected by HIV virus? What is the difference between HIV infection and AIDS?
HIV (Human Immunodeficiency Virus) affects CD4+ cells by entering and multiplying rapidly, destroying the cells in the process. Some of these CD4+ cells are CD4+ lymphocytes, which fight against infection. Hence, HIV weakens the immune system. This condition can lead to AIDS (Acquired Immune Deficiency Syndrome), in which the immune system is too weak to fight off regular infections, leading to otherwise harmless infections to become deadly.
1. How do natural killer cells differ from T-cells in their recognition of an enemy?
While natural killer cells and T-cells kill off invaders through a similar mechanism (contact followed by release of certain enzymes), they differ in their recognition of an enemy. T-cells have T-cell receptors that recognise particular antigens on the surface of invading cells and are thus relatively specific. Natural killer cells, on the other hand, simply look for whether or not an invader has a "self" marker on the cell surface, and can thus kill a wide variety of invaders. These markers are called major histocompatibility (MHC) antigens, and differ from person to person (except in the case of identical twins).
2. What cells are affected by HIV virus? What is the difference between HIV infection and AIDS?
HIV (Human Immunodeficiency Virus) affects CD4+ cells by entering and multiplying rapidly, destroying the cells in the process. Some of these CD4+ cells are CD4+ lymphocytes, which fight against infection. Hence, HIV weakens the immune system. This condition can lead to AIDS (Acquired Immune Deficiency Syndrome), in which the immune system is too weak to fight off regular infections, leading to otherwise harmless infections to become deadly.
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