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Homeostasis WK 9 Immune system

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winniesmith1's version from 2017-05-31 14:13

Section 1

Question Answer
What does the lymphoid system doprotects us against disease
What cells do the lymphoid system respond to Environmental pathogens, toxins and abnormal body cells, such as cancers.
What are pathogensOrganisms that cause disease- viruses, bacteria, fungi and parasites.
What are the 4 parts of the lymphatic system 1) Lymph(fluid), 2) lymphatic vessels (lymphatics), 3) lymphoid tissues and lymphoid organs, 4) lymphocytes and phagocytes
What is lymph fluid similar to plasma without plasma proteins
What do lymphatic vessels do carry lymph from peripheral tissues to venous system.
What are the 3 functions of the lymphoid system1. To produce, maintain, and distribute lymphocytes. 2. Return of fluid and solutes from peripheral tissues to blood. 3. Distribution of hormones, nutrients and waste products from tissue of origin to circulation.
How are lymphocytes producedIn lymphoid tissues (e.g. tonsils). Lymphoid organs (e.g spleen,thymus). In red bone marrow.
How are lymphocytes distributed Detects problem, travels into site of injury or infection.
Describe lymphatic capillaries not continuous capillaries, have dead ends.
Describe the difference between lyemphatic vessels and blood capillaries-Start as blind pockets rather than tubes -Have larger diameters -Have thinner walls -Flat or irregular in section -flaccid structure -has valves
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Section 2

Question Answer
Describe the lymphatic ducts Left side of the body, 3/4 goes to thoracic duct Right side of the body ¼ to lymphatic duct
What are the 3 types of circulating lymphocytes 1. T cells: thymus-dependent. 2. B cells: bone marrow derived. 3. NK cells: natural killer cells.
*production and distribution of lymphocytes diagram**page 13 of immune system lecture 1*
What are the lymph organs lymph nodes, thymus, spleen. Separated from surrounding tissues by a fibrous capsule.
What are the lymphoid nodules bundle of lymphoid tissue without fibrous capsule. e.g. tonsils, appendix; digestive system.
**lymphoid nodules diagram****page 15/16**
Describe lymph node circulation Lymph from Afferent Lymphatics Flows through lymph node in a network of sinuses: -From subcapsular space: contains macrophages and dendritic cells -Through outer cortex: contains B cells within germinal centers -Through deep cortex: dominated by T cells -Through the core (medulla): contains B cells and plasma cells, organized into medullary cords -Finally, into hilum and efferent lymphatics
What is the function of the lymph nodewhere armed interaction takes place.-A filter purifies lymph before return to venous circulation -Removes: Debris, Pathogens, 99% of antigens.
What are different types of lymph nodes distributed1. Lymph nodes of gut, trachea, lungs, and thoracic duct. 2. Lymph nodes (glands).
What do the lymph nodes of the gut, trachea, lungs and thoracic duct do Protect against pathogens in the digestive and respiratory systems.
What do the lymph nodes (glands) do Large lymph nodes at groin and base of neck. Swell in response to inflammation
What is lymphadenopathy Chronic or excessive enlargement of lymph nodes may indicate infections, endocrine disorders, or cancer
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Section 3

Question Answer
What is non-specific immunity innate, never changing, always there. -Block or attack any potential pathogen -Present from birth -No memory
What is specific immunity Adaptive. One part of the immune system responding to one specific disease, not born with it, but built up with exposure -Identify, attack and develop immunity to a specific antigen -Acquired in response to antigens -Has memory
What are nonspecific defences 1.Physical barriers 2.Phagocytic cells 3.Immunological surveillance (NK cells) 4.Interferons (antiviral) 5.Complement system 6.Inflammation 7.Fever
What is phagocytosis and antigen presentationThe pathogen is phagocytized by antigen-presenting cell (APC). Lysosome action produces antigenic fragments. These are bound to Class II MHC proteins (made by the ER). The antigenic fragments are displayed by the proteins on the cell membrane. To strongly signal other cells that these are bad and not self.
What are the classes of phagocytes Microphages and macrophages
What are microphages Neutrophils and eosinophils, Leave the bloodstream, Enter peripheral tissues to fight infections
What are macrophages Large phagocytic cells derived from monocytes, Distributed throughout body, Make up monocyte–macrophage system (reticuloendothelial system), May be fixed or free.
How do activated macrophages respond to pathogens - Engulf pathogen and destroy it with lysosomal enzymes - Bind to pathogen so other cells can destroy it - Destroy pathogen by releasing toxic chemicals into interstitial fluid
How do natural killer cells work Kill own body cells, such as host cells for viruses. 1) Recognition and adhesion. 2) Realignment of golgi apparatus. 3) Secretion of perforin. 4) Lysis of abnormal cell.
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Section 4

Question Answer
What are interferons Proteins (cytokines) released by activated lymphocytes and macrophages.
What are the 3 types of interferons -Alpha-interferons: Produced by leukocytes, Stimulate NK cells -Beta-interferons: Secreted by fibrocytes, Slow inflammation -Gamma-interferons: Secreted by T cells and NK cells, Stimulate macrophage activity
What do interferons do Increase resistance of cells to viral infection;slow the spread of disease.
What are complementsProteins always present in the body/blood.-11 complement (C) proteins -Complement antibody action -A chain reaction (cascade) 2 pathways of activation: classical pathway (fast) alternative pathway (slow). Conversion of inactive protein (C3) to active form (C3b)
What are the effects of complement activation -Stimulation of inflammation -Attraction of phagocytes -Enhancement of phagocytosis by opsonisation -Destruction of target cell membrane Five complement proteins join to form membrane attack complex (MAC)
Describe inflammation and the steps in tissue repairTissue is damaged. Inflammation causes chemical change in interstitial fluid. Mast cells release histamine and heparin. Area becomes red, swollen, warm and painful, due to dilation of blood vessels, increased blood flow, increased vessel permeability. This causes the formation of a clot. The mast cells also attract phagocytes, especially neutrophils, these release cytokines which cause the removal of debris by neutrophils and macrophages; stimulating fibrocytes and the activation of specific defences. Both of these pathways join to remove pathogens, clot erosion and scar tissue forms. Pg 31
What is a fever-Increase in body temperature due to release of pyrogens: Pyrogen – any material that causes the hypothalamus to raise body temperature
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