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71 Cards in this Set
- Front
- Back
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Fxn of Lymphatic System
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protection
maintain fluid homeostasis surveillance of body |
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3 types of lymphocytes
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B Cells: humoral immunity
T-Cells: Cell-mediated immunity Natural Killer Cells |
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Support cells of the lymphatic System
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present antigens to lymphocytes, help to regulate immune response
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Cluster of Differentiation (CD) Molecules
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unique cell surface markers found on Lymphatic and Hematopoietic cells
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Major Histocompatibility Complex (MCH)
HLA in humans |
ID molecule required for recognition of Ag by lymphocyte
displays small fragments of digested foreign proteins on surface |
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How do MHC work?
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bind to foreign peptides
take them to surface of cell, where cell can be recognized by lymphocyte |
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Where are MHC 1 found?
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found in all nucleated cells and platelets
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What receptors do MHC 1 recognize?
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T cell receptor (TCR)
CD8+ molecules (CTLs) |
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what cells does MHC 1 target?
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Abnormal Host (Self) cells
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What peptides does MHC 1 display?
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All peptides that are synthesized
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Fxn of Lymphatic System
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protection
maintain fluid homeostasis surveillance of body |
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3 types of lymphocytes
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B Cells: humoral immunity
T-Cells: Cell-mediated immunity Natural Killer Cells |
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Support cells of the lymphatic System
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present antigens to lymphocytes, help to regulate immune response
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Cluster of Differentiation (CD) Molecules
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unique cell surface markers found on Lymphatic and Hematopoietic cells
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Major Histocompatibility Complex (MCH)
HLA in humans |
ID molecule required for recognition of Ag by lymphocyte
displays small fragments of digested foreign proteins on surface |
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How do MHC work?
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bind to foreign peptides
take them to surface of cell, where cell can be recognized by lymphocyte |
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Where are MHC 1 found?
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found in all nucleated cells and platelets
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What receptors do MHC 1 recognize?
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T cell receptor (TCR)
CD8+ molecules (CTLs) |
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what cells does MHC 1 target?
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Abnormal Host (Self) cells
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What peptides does MHC 1 display?
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All peptides that are synthesized
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what receptors do MHC 1 react w/?
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T cell receptor (TCR)
CD8+ molecules (CTLs) |
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where is MHC 2 expressed?
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on the surface of Antigen Presenting Cells (APC)
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what does MHC 2 do in cells?
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presents partially digested foreign peptides to CD4+ helper T Cells only
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what receptors react w/ MCH 2 cells?
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only TCR and CD4 molecule of Helper T Cells
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what cells secrete Cytokines?
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activated Helper T Cells
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what systems do Cytokines fxn in?
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Autocrine (same cell) or Paracrine (neighboring cell) via binding cytokine to receptors
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What is the main fxn of Lymphocytes?
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70% circulating pool of immunocompetent cells
immunologic surveillance |
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What type of Lymphocytes reside in circulation?
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long-lived, mature T Cells
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Tissue Specific Lymphocytes
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30%, short-lived immature lymphocytes
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Where do T cells differentiate?
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Thymus
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What is the fxn of T cells?
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Cell-mediated immunity
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What do T cells Express?
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CD2, CD3, CD7 and T Cell Receptors (TCR's)
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Classification of T Cells:
CD4+ |
helper T Cells
interact w/ T and B cells |
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Classification of T Cells:
CD8+ |
Cytotoxic T Cells (Killer cells)
virus, cancer, transplant and parasites affected |
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Classification of T Cells:
ydelta T cells |
express neither CD8 or CD4
1st line of defense found at interface of internal/external environment |
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Where do B Lymphocytes Mature?
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Bone Marrow
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B Lymphocyte Fxn
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produce and secrete circulating Abs for Humoral immune response
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what do B Lymphocytes express?
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MHC 2
membrane-bound Ig called B-cell Receptors (BCRs) |
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Natural Killer Cells
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not considered T or B Lymphocytes
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what is the Fxn of NK cells?
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recognize viral or tumor cells
not restricted to cells w/ MHC |
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how do NK kill cells?
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similar to CD8+ T Cells
use Preforins and Fragmentins, which induce apoptosis |
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How do Antigen Present Cell (APC) work?
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endocytose Ag, breaking it down into 8-10 AA peptides
AA peptides are bound to MHC 2, transported to membrane |
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how do Macrophage (APC) break down MO?
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digest pathogenic MO via Lysosomes
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Macrophage Secretions
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Multiple Cytokines
IL-1, TNFa |
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Primary vs. secondary lymphoid organs?
Primary |
Primary: produce cells of immune system
bone marrow and thymus |
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Primary vs. secondary lymphoid organs?
Secondary |
where immune response occurs
lymphatic nodules, lymph nodes, tonsils, spleen |
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Types of Immune Responses:
Innate response |
Fast, non-specific
neutrophils, macrophages, mast cells, NK cells |
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Types of Immune Responses:
Adaptive response |
Slow and specific
requires Ag recognition by T and B cells forms memory cells |
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Primary (1st encounter) immune response
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1st encounter w/ Ag
lag period of several days before Abs/lymphocyte detection results in production of Ag specific B Cells (memory cells) |
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Secondary Immune Response
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more rapid due to memory cells
reason for immunization |
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Hypersensitivity Rxn
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intense secondary immune response resulting in tissue damage
caused by discharge of mast cell granules containing Histamine |
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Adaptive Immune Responses:
Humoral |
Ab-mediated
B Cell binds to Ag via MHC to acitivate causes secretion of Ab, which is targeted by NK cells or phagocytosis |
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Adaptive Immune Responses:
Cell-Mediated |
CTLs (CD8+) induce apoptosis of foreign cells and virally altered self-cells
also uses T Helper cells to induce Humoral Response |
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How do CTLs (CD 8+) cause apoptosis?
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release Perforins that generate pores in plasma membrane
release Fragmentins that enter pores and induce apoptosis |
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Activation of T Cells:
First Signal |
interaction of TCR and CD4/CD8 with Ag-MHC complex
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Activation of T Cells:
Second Signal |
interaction b/t membrane proteins on T Cells and APC
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Activation of Helper T Cells:
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release of Cytokines, which stimulate T Cells, B Cells and NK cells
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Activation of B Cells:
how many signals are needed? |
requires 2 signals
reacts w/ single Ag site |
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Activation of B Cells:
First signal |
interaction of BCR and Ag--> fragments of Ag + MHC 2 on surface
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Activation of B Cells:
Co-stimulatory signal |
T Helper Cell binds to B Cell, causing secretion of Cytokines
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Formation of Lymph:
Arterial End of Capillaries |
blood pressure> Osmotic pressure
water and electrolytes exit capillaries into extracellular space |
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Formation of Lymph:
Venous end of Capillaries |
Osmotic Pressure> blood pressure
fluid returns to capillaries |
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Where are Lymphatic Capillaries not found?
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bone, placenta, THYMUS
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Characteristics of Lymphatic Capillaries
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contain lymph and leukoctyes
no RBC |
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Lymphoid System Organization
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Diffuse Infiltration
Unencapsulated Lymphoid Nodules Encapsulated Lymphoid Organs |
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Diffuse Lymphatic Tissue (MALT)
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lymphocytes in loose clusters
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where is Diffuse Lymphatic Tissue found?
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lamina propria of GI, respiratory, and genitourinary tract
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Function of Diffuse Lymphatic Tissue?
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antibody formation via lymph nodes
initiate immune response |
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Unencapsulated Lymphatic Nodules:
Primary Nodules |
appear basophilic
consist of small lymphocytes and lack germinal center |
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Unencapsulated Lymphatic Nodules:
Secondary Nodules |
have germinal center in center
indicate immune response |
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Peyer's Patches
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found in Ileum
lymphatic nodules of T and B cells |
