Histology practical write up Essay Example | Topics and Well Written Essays - 1000 words

Histology practical write up - Essay Example Upon the maturation of the beneficial T cells, they are released into the blood. The thymus is a primary lymphoid organ (Paul, 2013). The spleen on its part is an immunologic blood filter. The spleen is of T cells, B cells, dendritic cells, natural killer cells, red blood cells and macrophages. The spleens functions by capturing antigens from the blood passing through the spleen. The migratory macrophages together with the dendritic cells transport the foreign bodies to the spleen through the blood stream. When the antigens get to the spleen and gets into contact with the appropriate B or T cells, an immune response is initiated. The B cells once activated produces large amounts of antibody which kills the antigen as well as aged red blood cells. The spleen contains two types of T-cells which are helper T-cells and killer T-cells. The helper T-cells are responsible for systematising the attack while the killer T-cells destroys the infected cell since it has then been turned into a virus reproduction factory. The spleen is a secondary lymphoid organ since it contains both T and B cells and requires an antigen entry to stimulate the lymphoid cells (Turgeon, 2014). Since the tissue sections are in wax, they are placed in hot plates for 2 minutes till all the wax is melted, and no traces of wax found in the tissues. Within a two-minute interval, the tissues are placed in absolute alcohol, 90% alcohol and 70% alcohol. In order to stain the tissues, they are placed in Ehrlich’s Haematoxylin for 45 minutes. Since this is a regressive stain, over stained tissues will have the stain solution removed with a tissue paper and rinsed for 30 minutes with tap water. The tissues should appear bluish purple/dark blue. The tissues are in acidic alcohol for 4 minutes and turn red. Immediately the slides are put into ammoniated alcohol and will turn blue. Within two-minute duration, the tissue

Greenhouse gasses Assignment Example | Topics and Well Written Essays - 500 words

Greenhouse gasses - Assignment Example The 19th century alone saw increase of 10 percent in carbon dioxide concentration in the earth’s atmosphere thanks to the burning of fossil fuels. It is being said that the Industrial revolution has contributed 40 percent to carbon dioxide and it is being estimated that if the activities continue at such pace the global temperature would rise by staggering 2 degree centigrade by 2050. The main constituents of green house gases are carbon dioxide itself, nitrous oxide, methane, sulfur dioxide, besides these gases, deforestation is a serious threat and every tree cut gives rise to emission of more carbon dioxide into the atmosphere. Deforestation results in rise in number of floods and droughts because the trees stop the flow of floods. This climate change will hit different parts of the world in different manner and it is being believed that dry regions would get further drier and temperatures would soar in those parts of the world where as cold and wet regions would get further wet and temperatures will remain low throughout the duration of year. The overall climate change will affect the available natural water, with rise in sea levels, the salt water would join the ranks of fresh water resources, and this can also result in increasing level of sediment. Existence of †Dead Zone† with low concentration of oxygen would be on a more frequent display .The Overall Scenario will have direct implications on human life in form of asthmas and other respiratory illnesses associated with heat waves and different environmental conditions. Ecology constitutes the study of overall natural system that encircles plants, animals, woodlots, lakes, and human beings themselves. Strong relationship exists between human beings and their surroundings. The mankind has a great impact on how the surroundings are today and how they will be 50 to 100 years down the lane. The Ecosystem in itself is at a great threat from