Bioguider

 When the body senses a shortage of blood cells , it sends signals to reactivate the yellow bone marrow. 1. Detection of Blood Cell Shortage In conditions like anemia , injury , or infection , there are not enough red blood cells (RBCs) or other blood cells. The body detects low oxygen levels or low cell counts in the blood.  2. Signal Release The kidneys release a hormone called erythropoietin (EPO) . Cytokines (immune signaling proteins) are also released. These signals reach the bone marrow through the blood.  3. Stem Cell Activation in Yellow Marrow The yellow marrow contains mesenchymal stem cells (fat-storing stem cells). Under normal conditions, these produce fat. But in response to signals (like EPO and cytokines), they start converting into hematopoietic cells (blood-producing cells). 4. Fat Cells Decrease Fat cells in yellow marrow shrink or die off . More space opens up for blood-forming cells to grow. 5. Re...

  Complement system is significant part of innate immune system.it contains 30 proteins in blood plasma and on the surface of the cell which will activate as a chain reaction (one will activate the next) Following are the major functions of complement system. Opsonization- label the microbes so that the phagocytic cells will get activated Chemotaxis-Attract the immune cells to the infected site Cell lysis- Forms a membrane attack complex (MAC) that can directly kill bacteria Clearance of Immune complexes- Helps to remove  antibody antigen complex from the body Pathways 1. Classical pathway classical pathway will be triggered by the antibodies and it comes under the part of adaptive immunity. Example If a person got infected with the measles virus . The body will start produced IgG antibodies against the virus. These antibodies bind to the virus. The classical pathway is activated to destroy the virus . classical pathway needs antibodies to induce the immune response . 2. Lect...