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LymphImmune System Katherine Lindberg Period 1 - Coggle Diagram
LymphImmune System Katherine Lindberg Period 1
Major Functions
protect body from illness-causing invaders
maintain body fluids
remove excess fluid from body tissues
absorb digestive tract fats
remove cellular waste
produce immune cells
Anatomy of Lymphatic System
Lymph nodes
function:cleanse lymph
function:site for lymphocyte activation and proliferation
stroma: reticular connective tissue
Spleen
function:cleanses blood and removes aged or defective red blood cells
function:site for lymphocyte activation and proliferation
function: stores platelets, monocytes, and iron
stroma: reticular conncetive tissue
MALT
function:prevents pathogens from penetrating mucous membrane
function:site for lymphocyte activation and proliferation
stroma: reticular connective tissue
Thymus
functions:site of T cell maturation
stroma: epithelial tissue
Innate vs Adaptive
Innate immune defenses
nonspecific
constitutes 1st and 2nd line defenses
1st line: external body membranes
mucosae
skin
2nd line: inhibit spread of invaders
microbial proteins
phagocytes
other cells
Adaptive immune defenses
specific
constitutes 3rd line of defense
attacks foreign substances
2 branches
humoral
cellular
innate and adaptive defenses are intertwined
both release and recognize the same defensive molecules
innate system releases proteins that alert cells of adaptive system to foreign molecules
Humoral vs Cellular
Humoral Immune Response
mediated by antibody molecules that are secreted by plasma cells
when B cell encounters target antigen, it provokes humoral immune response
antibodies are specific for particular antigen
Activation of B cells
B cells are activated when antigen binds to surface receptors
Active/Passive Humoral Immunity
Active: occurs when B cells encounter antigens and produce specific antibodies against them
artifically acquired: response to vaccine of dead pathogen
naturally acquired: response to bacteria infection
Passive: occurs when ready-made antibodies are introduced into body
naturally acquired: antibodies delivered to fetus via placenta
artificially acquired: injection of serum
Immunological Memory
primary response: cell proliferation/diferentiation upon exposure to antigen for first time
Secondary response: re-experinece to same antigen gives faster, prolonged, more efefctive response
Cellular Immune Response
doesn't involve antibodies
T cells provide defense against intracellular antigens
Activation of T cells: only activated when antigen is presented
activation is a 2 step process
Step 1: Antigen Binding
TCRs bind to antigen-MHC on APC surface
TCR must recognize both MHC and foreign antigen it displays
binding of TCR to complex triggers intralcellular signaling pathways that start cell activation
Step 2: Co-stimulation
compete T cell activation require T cell to bind to one or more co-stimulation signals on APC surface
Activation of CD8 cells
require TH cell to become activated into destructive cytotoxic T cells
Activation of B cells
helper T cells interact with B displaying fragments bound to MHC receptors
stimulate B cells to divide more rapidly
Antigens and antibodies
Antigens
substances that can mobilize adaptive defenses and provoke an immune response
self-antigens
all cells are covered with variety of proteins located on the surface that aren't antigens to self
MHC proteins are a group of glycoproteins
characteristics
can be self-antigen
contain antigenic determinants
can be complete antigen or hapten
Antibodies
basic structure
T or Y-shaped monomer
4 chains
2 heavy (H) chains
2 light (L) chains
antibody classes
IgA
IgD
IgG
IgE
IgM
proteins secreted by plasma cells
targets and functions
inactive and tag antigens
defense mechanisms
Precipitation: soluble molecules, crosslinked into complexes
Complement fixation: main antibody defense against cellular antigens
Agglutination: allows for antigen-antibody complexes to become cross-linked into large clumps
Neutralization: antibodies block specific sites on ciruses
cells involved
specific effector T cells
Cytotoxic T cells: directly attack and kill cells
activated cytotoxic T cells target:
cancer cells
foreign cells
virus-infected cells
cells with intracell bacteria
deliver lethal hit using two mechanisms
releases perforns and granzymes by exocytosis
binds on target cell and stimulates apoptosis
Regulatory T cells: prevent autoimmune reactions
Helper T cells: required for adaptive immunity
Activation of B cells
activate humoral/cellular, help activate B/T cells, include T/B proliferation, secrete cytokines that recruit immune cells
2 population of T cells
CD4 cells: become helper T cells that can activate B cells; direct adaptive immune response
can also become memory T cells
can become regulatory T cells
CD8 cells: become cytotoxic T cells
disorders
Immune Problems
Hodgkin's: a blood cancer that causes cancer of B cells
SCID syndrome: genetic defect with a marked deficit in B and T cells
Immunodeficiency: congenital conditions that repair immune cells
AIDS: acquired immunodeficiency syndrome
HIV: interferes with activity of helper T cells
Autoimmune Diseases
Autoimmunity: production of auto antibodies and sense Tc cells that destroy body tissue
Treatment includes suppression of entire immune system
results when immune system loses ability to distinguish self from foreign invaders
Hypersensitivity
systemic response is anaphylactic shock
Immediate hypertens
asymptomatic: initial contact with allergen
acute: seconds after contact with allergen
immune response to perceived threat that cause tissue damage