Immunology

Through contact, transfer of bodily fluids, droplets, ingestion, airborne transmission, vectors

Works against all pathogens, and consists of external defences, leucocytes and macrophages, the inflammatory response

• Mast cells release histamine, heparin into extracellular fluid • Histamine increases blood flow in the area by increasing the permeability of capillaries; causes heat and swelling • Heparin prevents blood clotting • Chemicals released by mast cells attract phagocytes • Abnormal conditions stimulate pain receptors

increases capillary permeability, hence blood flow in area; causes heat and swelling

Prevents blood clotting

High body temperature inhibits the growth of bacteria and viruses, increases the rate of chemical reactions. Can be harmful if exceeds 44 C

consists of all external barriers; skin, mucous membranes, sebaceous secretions

Protect the body from injury and infection - sneezing, coughing, vomiting

collects excess extracellular fluid and returns it to the circulatory system

contains lymphoid tissue that traps large particles such as bacteria

High body temperature inhibits the growth of bacteria and viruses, increases the rate of chemical reactions. Can be harmful if exceeds 44 C

Directed towards a specific pathogen

Mature in the bones, found in the blood and lymphoid tissue; involves in humoral and cell-mediated immunity

Matures in the thymus, found in lymph nodesl involved in cell-mediated immunity

Any substance capable of causing a specific immune response

recognised by the immune system as belonging to the body - don’t cause an immune response

recognised as not belonging to the body - triggers an immune response

• Antigen sensitises B cell • B cell enlarges, clones Either form plasma cells or memory cells • Memory cells respond to re-exposure of antigen (secondary response), while plasma cells/antibodies attack antigens

Combine with bacterial/ viral toxins/ enzymes and inhibit them Bind to viruses to prevent cell entry Coat bacteria – easier phagocytosis Cause agglutination of foreign particles Create insoluble substances – easier phagocytosis

• B cell/macrophage encounters antigen and presents it to nearest lymph node • T cell becomes sensitised • T cell enlarges and clones into 3 types of T cells or memory cell

migrate and attach to invading cells

cause more lymphocytes to become more sensitized, attracts macrophages and intensifies phagocytosis

Releases substances that inhibit B and T cell activity

Natural, artificial, passive, natural