722943
Description
Flashcards by Morgan Morgan, updated more than 1 year ago
|
Created by Morgan Morgan
over 10 years ago
|
|
| Question | Answer |
| Non-specific | Non-specific – inborn (‘innate’), general , fast Works against any type of invading agent |
| Specific | Acquired following exposure to specific pathogen; slower response. |
| 2 Main categories of WBCs | Granulocytes & agranulocytes |
| Neutrophils | Most commont - 50-70% of total Phagocytic 1st on scene at infected site Short-lived |
| Eosinophils | 2-4% of WBCs Weak phagocytes Effective against parasitic worms Anti-histamine properties |
| Basophils | 0.5-1% of WBCs Release histamine (dilates BVs) & heparin (anti-coagulant) from granules |
| Lymphocytes | 20-30% of WBCs 3 Types B-cells T-cells Natural killer cells |
| Monocytes | 3-8% of WBCs 12-20um Kidney-shaped nucleus Leave blood &enter tissues; transform into macrophages which phagocytose microbes ‘Fixed’ or ‘wandering’ |
| A macrophage extends a .............to pull in and engulf a bacterium. | pseudopod |
| Lymphatic System | Network of vessels which transport excess fluid away from interstitial spaces & return it to bloodstream Helps defend body against disease-causing agents. |
| Organs of the lymphatic system include? | Lymph nodes Spleen Thymus Tonsils |
| Parts of the Lymphatic System - Lymph? | A fluid similar to plasma but no plasma proteins |
| Lymphatic vessels (lymphatics)? | Carry lymph from peripheral tissues to the venous system |
| LYMPH NODES | Located along length of lymphatics, these filter lymph, trapping bacteria, etc. Lymphocytes in nodes attack & destroy microbes Swell during an infection due to ↑lymphocyte numbers. |
| Spleen | Largest lymphatic organ Site of B-& T-lymphocytes proliferation during infection. Phagocytosis of bacteria & old & damaged RBCs. Blood store –rupture of spleen causes severe blood loss & shock (low BP). |
| Thymus | 2-lobed organ behind sternum. Site of T-cell maturation. Produces hormones which promote maturation of T-cells. Most active during early life-critical role in development of immune system before birth & during childhood. Reaches maximum size at puberty& shrinks thereafter. |
| Tonsils | Group of lymph nodes at back of throat Produce lymphocytes and antibodies which defend against swallowed or inhaled microbes |
| Non-specific Resistance - Physical barriers | Intact skin Mucous membranes Hairs in nostrils (filter) Cilia in trachea (sweep particles away) |
| Chemical barriers | Stomach acid:- strongly acidic gastric juice kills most bacteria swallowed in food Sweat /sebaceous glands:- secrete bacteriocidal & fungicidal substances Lysosyme:- powerful bacteriocidal enzyme in tears, saliva, nasal secretions |
| Natural Killer (NK)Cells | Non-specific type of lymphocyte which attack & destroy a variety of cancer cells & virus-infected cells. Bind to cancer cell, release perforin which perforates cell membrane, killing cell. |
| Interferons | Proteins produced & released by virus-infected cells. INFs diffuse to neighbouring uninfected cells & bind to receptors. Induce production of anti-viral proteins which prevent viral replication in healthy cells. |
| Fever (pyrexia) | Chemical (pyrogens) released from damaged tissue act on hypothalamus (thermostat). ‘Thermostat’ re-set to higher temp. Increased body temperature: Inhibits microbial growth Speeds up tissue repair. |
| Summary of non-specific defences - 2nd line of defense? | Phagocytosis Complement Inflammation Interferon Fever NK cells |
| Any foreign substance which triggers an immune response is called an ....... (e.g.bacteria, viruses, transplanted tissue, pollen ,etc) | Antigen |
| Immune system remembers a particular antigen & responds much faster on 2nd exposure. Immune system can recognise & remember millions of antigens that may invade body. 2 types of lymphocytes involved? | B-lymphocytes (B-cells) T-lymphocytes (T-cells) |
| B- & T-cells are derived from ? | stem cells in bone marrow. |
| Immature T-cells must pass to the.......where they gain specificity. | thymus |
| B Cells provide? Defend against? | Provide antibody-mediated immunity. Defends against antigens and pathogens in body fluids i.e. outside cells. When activated, become plasma cells which produce antibodies. |
| T Cells provide? Defend against? | Provide cell-mediated immunity. Defends against abnormal cells (cancer cells ,transplanted cells) and pathogens inside cells (e.g.viruses) |
| Each T or B cell: responds only to a ...... antigen ignores all others | Specific |
| On exposure to specific antigens, .......are activated & transform into ...... cells which produce ......... which inactivate the antigen. Antibodies are proteins-immunoglobulins They are y-shaped molecules with specific receptor sites to bind specific antigen Used to attack free bacteria & viruses in body fluids (i.e extracellular pathogens) | B-cells plasma cells antibodies |
| Cell-mediated immunity (T-cells) | Method used for attacking virus-infected cells, cancer cells ; transplanted cells. Specific T-cells are activated (sensitized) when antigen is presented to it by an antigen-presenting cell , usually a macrophage. Sensitized T-cells then enlarge, differentiate & divide into a clone. Within clone, there are 4 types of T-cells |
| Helper T-cells | Identify virus-infected cells (or foreign cells) by presence of ‘non-self’ antigens on cell membrane. Help activate cytotoxic T-cells which attach to & kill infected cells. Induce antibody production by B-cells. HIV specifically attacks Helper T-cells, resulting in suppressed immune response |
| Cytotoxic (killer) T-cells | Recognise ‘foreign’ cell by ‘non-self’ antigen displayed on surface of cell membrane. Attach to infected, cancer or transplanted cell & release a chemical (perforin) which bursts cell membrane. |
| Suppressor T-cells | Dampen down the immune response once the infection is overcome. |
| Active Immunity | Long-lasting protection resulting from exposure to a particular antigen. Results in production of antibodies , T-cells & memory cells. Can be acquired naturally following exposure to the disease-causing pathogen or artificially by injecting weakened version of antigen i.e. vaccination (e.g.MMR, etc). |
| Passive Immunity | Temporary, short-term protection gained by receiving ready-made antibodies produced by another person. Natural passive – mother’s antibodies protect fetus & new-born baby by crossing placenta and presence in breast milk. Artificial passive – injection of ready-made antibodies given for serious, life-threatening conditions –e.g. tetanus, rabies |
Want to create your own Flashcards for free with GoConqr? Learn more.