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23 Cards in this Set
- Front
- Back
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Types of Defense Mechanisms
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1. Innate Immunity- (always there) rapid responses to a broad range of microbes. Ex: external defenses (skin, mucuous membranes, secretions); internal defenses (phagocytic cells, antimicrobial proteins, inflammatory response, natural killer cells(they nonspecifically target foreign cells)
2. Acquired Immunity- (slower but more specific) a slower response to specific microbes. Ex: humoral responses (production of antibodies); cell-mediated response (cytotoxic lymphocytes. It is mediated by specific T lymphocytes that attack and destroy virus-infected host cells or foreign cells. It is important in the defense against viral, fungal and mycobacterial infections) |
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Innate Immunity:
Phagocytic cells |
- Neutrophils (60%)- self destructive (short lifespan)
- Macrophages- transient or resident (in spleen, nodes) - Eosinophils- worm killers - Dendritic cells |
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Innate Immunity:
Antimicrobial |
- Complement system- 30 proteins that travel through the body and recognize antigens on bacteria (they either kill bacteria directly or inhibit them from replication)
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Innate Immunity:
Inflammatory Response |
- Dilation and Permeability- to bring in macrophages, etc to come and fight off infection
- Recruitment and Clotting |
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Cells of Innate Response
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*Mast Cells
*Phagocytes: - Macrophages - Neutrophils - Dendritic Cells *Basophils and Eosinophils *Natural Killer Cell- target host cells that have become infected (in a nonspecific manner. They are specialized to kill certain types of target cells. |
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Kinds of Acquired Immunity
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* Humoral- antibodies from plasma cells; B cells form the plasma and produce them. It activates B lymphocytes which replicate to form plasma cells (which produce specific antibodies)
* Cell-Mediated- Cytotoxic T cells. They divide into cytotoxic (killer) T cells which kill the host cell |
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Three Main Cell Types of the Immune Response
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- Lymphocytes (B and T)
- Natural Killer Cells - Antigen-presenting cells |
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B Lymphocytes
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- B= bone marrow
- 20-30% of lymphocytes - bone and GALT maturation - two types of cells that come from immature B cell: Memory B cells and Plasma Cells |
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T Lymphocytes
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- 70% of lymphocytes
- they mature in the thymus (thymus maturation) - three main types: Memory T cells Helper T cells (Th) Cytotoxic T cells (Tc) |
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Helper T Cell
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- macrophage breaks up antigen and puts it on surface. Helper T cell comes in and recognizes it and T cell becomes activated. It sends signal to either cytotoxic T cells or to B cells to have them become plasma cells
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The concept of vaccines
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- first exposure to antigen A: (primary immune response) body produces antibodies to antigen A. The response is characterized by a lag period of several days before antibodies can be detected in the blood. The initial response is inititaed by only one or a few B lymphocytes that have been genetically programmed to respond to that specific antigen)
- second exposure to antigen A: (secondary immune response) much higher to antigen A than the first response. It is more rapid and more intense (characterized by higher levels of secreted antibodies) because of the presence of specific memory B lymphocytes already programmed to respond ro that specific antigen. |
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Lymphatic System
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- four places we're worried about: spleen, thymus (those are the two main organs), lymph nodes and tonsils
-there are interactions between capillaries and lymphatic |
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Lymphatic Components
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- the difference between the two is whether or not they're encapsulated (surrounded by a capsule)
1. Diffuse Lymphatic Tissue- no capsule; ex: lymphnoid nodules 2. Nodular Lymphatic Tissue- capsule present; ex: lymph nodes, tonsils, spleen, thymus |
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Diffuse Lymphatic Tissue and Nodules
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- diffuse tissue- located just underneath epithelium (regions prone to invasion). Diffuse area.
- Nodule- active immune response taking place. It has a more defined shape with a darker outside and a lighter germinal center |
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Interaction between T and B lymphocytes
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look at figure
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Lymph Nodes
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- small encapsulated organs located along the pathway of lymphatic vessels
- filter lymph with blood - have a convex side- where smaller lymphatic vessels enter - have a concave (hilum) side- where the big blood vessel enters Layers: cortex (B lymphocytes); deep cortex or paracortex (T lymphocytes); medulla |
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Lymph Nodes- function and flow
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- septa extend into lymph node
- sinuses have lymphocytes that fight off infection (pathogens cleaned out of blood) - the fluids are cleaned either through the circulatory system or the lymphatic system |
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Tonsils
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- considered to be encapsulated
- three groups: 1. Pharyngeal- a single diffuse tonsil 2. Palatine- large tonsils at walls of oral pharynx; have deep crypts (these are the ones we think about when we hear the word tonsils); they are a large aggregation of nodules. 3. Lingual- at the base of the tongue |
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Thymus
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- produces T lymphocytes and makes sure they recognize foreign antigens (education)
- it is a bilobed lymphatic organ - usually the thymus gets smaller as we get older but in an alcoholic it gets larger - the thymus has a cortex and medulla |
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Thymus Education
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- lymphnodes travel from the medulla to the cortex and interact with the epithelial reticular cells (ERC).
- then they make different CD proteins. - the T lymphocytes that bind get to move on into the deeper cortex toward the medulla. - 2nd section: the "self antigen" cells are eliminated, leaving only active cells that act against foreign antigens. |
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Thymus Blood-Brain Barrier
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- there are multiple barriers separating the inside of the thymus. This isolates the education process from foreign antigens that may be in the circulatory system.
- so it is not a permeable barrier |
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Spleen
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- the largest lymphatic organ in the body
- function: filter blood from microbes and broken down RBC. Also to produce T and B lymphocytes. - no medulla or cortex - instead there are regions called red pulp or white pulp - Red Pulp= open sinuses and cords (made up of macrophages, plasma cells). Red pulp contains large numbers of RBC that it filters and degrades. - White Pulp= areas that look like nodules (have a central germinal area and darker outside area). Have a blood vessel going through the center. The white pulp consists of lymphatic tissue, mostly lymphocytes. |
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Spleen circulation
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- no lymphatic ducts, just a circulatory system
- circulation within red pulp allows macrophages to screen antigens in the blood - splenic nodule - PALS- lymphocytes that aggregate around the central artery. - sheathed capillaries - its either an open or closed circulatory system (we don't know which one) - the spleen performs both immune and hemopoietic functions (because it filters blood) |
