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Emily Saldivar- P.1 LymphImmune System - Coggle Diagram
Emily Saldivar- P.1 LymphImmune System
Major Functions of the Lymphatic & Immune Systems
Immune System
lines of defense that provide resistance to disease
Lymphatic System
returns leaked fluid from vascular system back into the blood
structural basis for immune system
help body's defense and resistance to disease
Innate (natural) immune defenses & Adaptive (acquired) immune defenses
Innate Defense System
1st Line- external body membranes
skin & mucous membranes- physical barrier, keratin resistant, and have chemicals that destroy microorganisms
Acid- acidity of skin & might inhibit growth, called acid mantle
Enzymes-in saliva, respiratory mucus & lacrimal fluids and kill many microorganisms
Mucin- sticky mucus that lines digestive + respiratory tract & traps microorganisms
2nd Line- Cells & Chemicals
necessary if microorganisms invade deeper tissues
Phagocytes- white blood cells that ingest + digest foreign invaders
Neutrophils- most abundant, die fighting, and become phagocytic when exposed to invader
Macrophages- develop from monocytes & are the main phagocytic cells
Natural Killer Cells- non-phagocytic lymphocytes that patrol the blood & lymph. Can induce apoptosis in cancer & virus infected cells + secrete chemicals to trigger inflammatory response
Inflammation- triggered when tissues are injured, disposes of cell debris + pathogens & prevents spread of damaging agents
Stages of Inflammation
Inflammatory Chemical Release- chemicals released into ECF by injured tissue or immune cells
Vasodilation & Increased Vascular Permeability- causes vasodilation of local arterioles, make capillaries leaky & attract phagocytes to area
Phagocyte Mobilization- when neutrophils flood the area first & macrophages follow
Antimicrobial Proteins (interferons & complement proteins)
Fever
Adaptive Defense System
specific defense system that eliminates almost any pathogen or abnormal cell in the body
Humoral Immunity
antibodies circulate in body fluids
bind temporarily to target cell
marks for destruction
Cellular Immunity
lymphocytes act against target cell
directly- by killing infected cells
indirectly- by releasing chemicals or activating lymphocytes or macrophages
Cells involved in the Immune System
Lymphocytes
B Cells (Humoral)- produce antibodies and mediates production of antigen-specific immunoglobulin
T Cells (Cellular)
Helper T Cells (CD4)- can activate B cells, other T cells & macrophages. Central cell in adaptive immune system
Cytotoxic T Cells (CD8)- can destroy cells carrying foreign antigens
Regulatory T Cells- moderate immune response & can become memory cells
Naive T Cells- fights off new & unrecognized pathogens, + can become regulatory T cells
Phagocytes
Neutrophils- most abundant phagocyte and becomes phagocytic when exposed to pathogen & dies fighting. Part of 2nd line of defense
Macrophages- developed from monocytes and are the main phagocytic cell. Part of 2nd line of defense
Antigen Presenting Cells
Dendritic Cells- in connective tissues & epidermis, acts as mobile sentinels of boundary tissues + phagocytize pathogens that enter
Macrophages- presents antigens to T cells which activates & further activates macrophage. Becomes phagocytic killer + can trigger inflammatory response
B Cells- presents antigens to helper T cells to help in their own activation
Anatomy of the Lymphatic System
Primary Lymphoid Organs
Thymus- site of T cell maturation
Red Bone Marrow- site of B cell maturation
Secondary Lymphoid Organs
Lymph Nodes- cleans lymph and is site for lymphocyte activation and proliferation
Spleen- cleans blood + removes defective red blood cells, site for activation & proliferation, and stores platelets, monocytes and iron
Mucosa Associated Lymphoid Tissue (MALT)- prevent pathogens from penetrating mucous membrane & site for activation and proliferation
Appendix
Tonsils
Disorders associated with the Immune System
Pus- creamy yellow mixture of dead neutrophils, tissue, and living + dead pathogens
Abscess- collagen fibers laid down, walling a sac of pus that may need to be surgically drained
Immunodeficiencies
Immunodeficiency- congenital or acquired conditions that impair function or production of immune cells
Severe Combined Immunodeficiency Syndrome (SCID)- genetic defect with marked deficit in B & T cells
Hodgkin's Disease- causes cancer of B cells and depresses lymph node cells
Human Immunodeficiency Virus (HIV)- cripples immune system by messing with Helper T Cell activity
Autoimmune Diseases
Rheumatoid Arthritis- destroys joints
Myasthenia Gravis- impairs nerve to muscle connections
Grave's Disease- hyperthyroidism
Type 1 Diabetes Mellitus- destroys pancreatic cells
Systemic Lupus Erythematosus- immune disorder affecting multiple organs
Glomerulonephritis- damages kidney
Antigens & Antibodies
Antibodies (Immunoglobins)- proteins secreted by plasma cells & is grouped into 5 classes
Antibody classes
IgM- secreted in primary response
IgA- found in body secretions
IgD- functions as B cell antigen receptor
IgG- most abundant in plasma & main antibody of secondary + late primary response
IgE- binds to mast cells & triggers cells to release histamine
Antigen-antibody complexes prepare them for destruction through innate defenses
Antibodies go after extracellular pathogens & don't invade solid tissue unless a lesion is there
Basic Structure- Overall T or Y shaped antibody monomer & consists of 4 looping polypeptide chains linked by disulfide bonds
Antigens- substances that can mobilize adaptive defenses + initiate immune response
Targets all adaptive immune responses & most are large, complex molecules not normally in body
Can be complete or incomplete + a self-antigen
All cells covered in a variety of proteins located on surface that are not antigenic to self but can be in a graft or transfusion
Important set of self-proteins are a group of glycoproteins called major histocompatibility complex (MHC) proteins
T cells can only identify antigens that are presented on MHC proteins
Humoral Response + Cellular Response
Humoral- when B cell encounters target antigen, humoral response is initiated
Receptor mediated endocytosis is triggered (clonal selection) & leads to proliferation and differentiation of B cells into effector cells
Most clone cells become plasma cells, which secrete antibodies
Antibodies circulate in the blood or lymph nodes, bind to free antigens & mark for destruction
Clone cells that don't become plasma cells become memory cells
Primary Immune Response- cell proliferation & differentiation when exposed to antigen for 1st time
Secondary Immune Response- re-exposure to same antigen that gives a faster and more effective response
Active + Passive Humoral Immunity
Active Humoral Immunity- B cells encounter antigens & produce specific antibodies against them
Naturally Acquired- formed in response to pathogen
Artificially Acquired- formed from vaccine
Passive Humoral Immunity- ready made antibodies introduced into body
Naturally Acquired- antibodies delivered to fetus via placenta or through milk
Artificially Acquired- injection of serum, like gamma globulin
Cellular- T Cells provide defense against intracellular antigens
Some T cells directly kill cells, while others release chemicals that regulate immune response
T cells only activated when antigen is presented to them & is 2 step process
Antigen Binding- T cell antigen receptors bind to antigen-MHC complex on APC surface & receptor must recognize both MHC & foreign antigen displayed
Co-Stimulation- complete T cell activation that requires T cell to bind to one or more co-stimulatory signals of APC
CD4 cells activate B cells, other T cells & macrophages (direct adaptive immune response)
CD8 cells can destroy cells harboring foreign antigens (moderate immune response)