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Ch.8: Lymphatic System – Intro to Immunology
Notes on Ch.8 Lymphatic System in regards to how the Immune system ope...
Course
Histology (BIOL 4003)
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Students shared 23 documents in this course
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Auburn University
Academic year: 2018/2019
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Histology Chapter 8 – Lymphatic System Pt. Introduction of Immunology
A. Introduction of Immunity a. Two main groups of immune response: Innate vs. Adaptive i. Innate 1. Nonspecific 2. Initial response ii. Adaptive
- Specific
- Takes a little bit longer
- Involves Lymphocytes & Antigen Presenting Cells (APC) B. Lymphoid Organs & Diffuse Lymphoid Cells a. Primary Lymphoid Organs – Lymphocytes being formed i. Thymus ii. Bone Marrow b. Secondary Lymphoid Organs – Lymphocytes activated or proliferate i. Lymph Nodes ii. Spleen iii. Diffuse Lymphoid Tissue (Tonsils, Peyer’s Patches, Appendix) c. Diffuse Lymphoid Cells i. Mucosa Associated Lymphoid Tissue ( MALT ) 1. In digestive, respiratory, and urogenital mucosae ii. May contain lymphoid nodules that have proliferation and activation happening, but often times it is just a concentration of lymphatic cells in an area of infection or inflammation C. Innate Immunity a. Physical Barriers i. Skin ii. Mucosal Layer b. Neutrophils i. Can act quickly to remove bacteria, fungi, or parasites c. Toll Like Receptors (TLRs) – On Leukocytes i. Will allow recognition and binding of the surface components of the invaders d. Natural Killer (NK) Cells i. Can destroy unhealthy host cells (ones that have been infected with viruses or bacteria) ii. Also important in tumorigenic cells (cells that form tumors) e. These cells will produce antimicrobial chemicals that are crucial in innate immunity i. Hydrochloric Acid (HCl) & Other Various Organic Ac ids 1. Lower pH 2. Lowered pH (locally) can kill or inhibit the growth of microorganisms
ii. Defensins – produced by Neutrophils 1. Kill bacteria by disrupting the cell wall of the bacteria iii. Lysozyme – Enzyme made by Neutrophils & cells of the epithelial barriers
- Can hydrolyze bacterial cell walls iv. Complement
- System of proteins that is found in blood plasma and mucus
- Macrophages are involved in this secretion and this reacts with bacterial cell surface components and it aids in the removal of bacteria v. Interferons
- Paracrine factors from leukocytes and virus-infected cells that can signal the NK cells D. Adaptive Immunity a. Acquired gradually through exposure b. More specific c. Slower to respond d. B & T Lymphocytes are involved i. They become activated against specific invaders by an antigen producing cell ( APC ) e. Memory Lymphocytes may be produced during the response i. Which can mount a subsequent response pretty quickly if that specific invader reinfects
E. Cytokines a. Allow the various components of the immunity to communicate and coordinate the immune response b. Part of both innate and adaptive immunity
- It can cross the placental barrier and into fetal circulation a. This can create passive immunity for the fetus against certain infections until the newborn’s immune system is fully acquired ii. IgA – Second most common (10-15%)
- Present in exocrine secretions (saliva, milk, tears) as a dimer a. So it has a J-Chain binding to Y-shaped antibodies
- Protects the mucosa iii. IgM – Pentamer (J-chains bind it into the pentamer shape)
- Initial response
- Binds to the antigen and can activate complement iv. IgE – 0%, involved in allergies
- Monomer
- It is bound to the Fc region to the receptors on the surface of mast cells and basophils
- When the antigen binds to IgE it triggers the liberation of histamine, heparin, leukotrienes a. Which cause an allergic response v. IgD – least abundant/understood
- Monomer bound to the surface of B lymphocytes where it can act as an antigen receptor
- Seems to trigger B-Cell activation c. Functions of Antibodies When They are Bound to an An tigen: i. Neutralization of the Antigen
- Basically it covers the biologically active portion of the invader and neutralizes it ii. Agglutination
- When the antibodies will cross-link cells to form a “clump” iii. Precipitation
- An antibody binds to particles and forms an insoluble antigen-antibody complex, so they precipitate out of solution d. Exposed Fc Portion Following Antigen Binding by Ant ibody Promotes: i. Complement Fixation ii. Opsonization
- When the Fc region will bind to receptors on phagocytic cells to trigger phagocytosis iii. Activation of NK Cells
- Fc region of the antibody binds to an NK cell and triggers the release of cytotoxic chemicals G. Antigen Presentation (Major Histocompatibility Complex – MHC) a. Complex that will be a part of the integral membrane protein complexes b. Important in Recognizing Self
c. MHC 1 – Bind to a wide variety of proteasome-derived peptide fragments that represent a range of all proteins within the cell that they are presented on i. T-Cells can recognize these self-antigens and then ignore them d. MHC 2 – Are synthesized and presented ONLY in cells of the mononuclear phagocyte system i. Will bind fragments of whatever proteins the cell has ingested ii. Will display the peptide and signal the T-lymphocytes, activating the response against the antigen
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Ch.8: Lymphatic System – Intro to Immunology
Course: Histology (BIOL 4003)
23 Documents
Students shared 23 documents in this course
University: Auburn University
Was this document helpful?
Hoosier 1
Histology
Chapter 8 – Lymphatic System Pt.1
Introduction of Immunology
A. Introduction of Immunity
a. Two main groups of immune response: Innate vs. Adaptive
i. Innate
1. Nonspecific
2. Initial response
ii. Adaptive
1. Specific
2. Takes a little bit longer
3. Involves Lymphocytes & Antigen Presenting Cells (APC)
B. Lymphoid Organs & Diffuse Lymphoid Cells
a. Primary Lymphoid Organs – Lymphocytes being formed
i. Thymus
ii. Bone Marrow
b. Secondary Lymphoid Organs – Lymphocytes activated or proliferate
i. Lymph Nodes
ii. Spleen
iii. Diffuse Lymphoid Tissue (Tonsils, Peyer’s Patches, Appendix)
c. Diffuse Lymphoid Cells
i. Mucosa Associated Lymphoid Tissue (MALT)
1. In digestive, respiratory, and urogenital mucosae
ii. May contain lymphoid nodules that have proliferation and
activation happening, but often times it is just a concentration of
lymphatic cells in an area of infection or inflammation
C. Innate Immunity
a. Physical Barriers
i. Skin
ii. Mucosal Layer
b. Neutrophils
i. Can act quickly to remove bacteria, fungi, or parasites
c. Toll Like Receptors (TLRs) – On Leukocytes
i. Will allow recognition and binding of the surface components of
the invaders
d. Natural Killer (NK) Cells
i. Can destroy unhealthy host cells (ones that have been infected
with viruses or bacteria)
ii. Also important in tumorigenic cells (cells that form tumors)
e. These cells will produce antimicrobial chemicals that are crucial in
innate immunity
i. Hydrochloric Acid (HCl) & Other Various Organic Acids
1. Lower pH
2. Lowered pH (locally) can kill or inhibit the growth of
microorganisms
