Human Disease and Their Control follow up questions 1a) When people refer to pathogens, they are talking about bacteria that cause disease. 1b)The toxins actually excreted by the pathogens are the main cause of diseases although thetoxins are only by-products of the pathogen's metabolism. 2a)In most cases, the toxins excreted by the pathogens find there way into the circulatory system. Thus, sometimes, the infection is caused somewhere else from where the toxins were excreted. An example of this would be Rheumatic fever. The toxins that ca Yet another example of where the disease is in a different location then where the toxin was released is Dipheria. The pathogen that causes Diptheria is usually located in the throat. As the toxin is released, it travels all the way to affect limb muscle 2b) Examples of where the disease is at the site of the bacteria could be Tetanus and Tuberculosis. The tetanus bacteria releases a deadly toxin which can affect the whole body which causes paralyzation. As it affects the whole body, the disease would mos 3a) In our environment, we encounter all sorts of micro-organisms. Sometimes these air-borne diseases are pathogens and could cause and make one sick. Examples of air-borne pathogens that cause diseases are the ones that cause whooping cough, scarlet feve 3b) An example for this kind of transmission would be the kind of pathogens found in feces. Typhoid fever is one of the kinds of diseases that are transmitted through water as these pathogens are found in feces. The feces released would sooner or later fi 4a) Besides transmitting disease through everyday drinking water and the air, another way of transmitting diseases are by contact. Chicken Pox and Small Pox are some of the many diseases that can be caused by contact. 4b) Veneral diseases like gonorrhea and syphilis can also be transmitted by contact. 5a) An example of a disease that can be transmitted if there is a wound would be our very familiar Tetanus. An example of how someone would acwuire tetanus from a wound would be like this: The construction worker moves around a lot and works very hard. Down on the floor is a tetanus infected nail. As the worker is too busy caring for his job, he accidently steps on the nail and gives the tetanus bacteria a chance to get into the body. The 6a) Immune carriers can be classified as those who have recovered from a certain disease and is immune to it, but still carries the pathogens. The immune carriers show no indecation of a disease with no symptoms, but this carrier can still trnasmit these 6b) One major disease carrier is the Anthropod. They pick up the pathogens in their food, where they walk and other places. As they carry the disease, they move to other places either for food or shelter purposes. When they bite or sting other organisms, 7) The skin is the main protector from pathogens. The first line of defense is the structure of the skin itself. It is almost impossible for pathogens to pass the skin layer. Those who do would go through the pores in our skin. The second line of defense 8a) Some cells that engulf pathogens are known as phagocytes. This is so because the phagocytes engulf the pathogens through a special process known as phagocytosis. An example of a phagocyte would be blood cells known as leucocytes. The whole job of thes 8b) What many people refer to as Pus is actually the left overs of dead leucocytes and pathogens. 8c) Serious infections cause the swelling of the nymph nodes as there are too many dead leucocytes and pathogens to store for excretion from the body. 9a) Antigens are foriegn proteins to the human body. In turn, these foreign proteins cause a reaction. Usually, the main cause of these foreign proteins would be toxins from pathogens or micro-organisms. 9b) When an antigen enters the body, a certain reaction occurs. When it has been found out that an antigen really is present, it causes the spleen and the lymph nodes to produce a substance known as antibody. This antibody is a specifically desgined aubst 9c) An antitoxin is a kind of antibody. This kind of antobody is specifically used to go after