Lymphatic Immune System Mia Cortez Period 5
Lymphatic System
Major functions
Lymphatic vessels collect and carry away excess tissue fluid from interstitial spaces eventually returning it to the blood
Drains tissue fluid,waste products, & fights against infection
Organs
Thymus
Spleen
Lymph Nodes
Locations: Cervical, pelvic, thoracic, axillary, supratrochlear, abdominal. & inguinal regions
Functions:
Filter lymph & remove bacteria/ cellular debris before lymph is returned to blood
Immune surveillance: Monitors body fluids
Lymphocytes attack viruses, bacteria, & parasitic cells that enter a lymph node ; Macrophages engulf & destroy foreign particles, debris & damaged cells
Location: In the thoracic cavity, superior to the heart
Function: Provide immunity
Location: Next to stomach, behind ribs
Function: Filters blood & removes dead blood cells & bacteria
Antigens and Antibodies
Antigen
Antibodies
Can be any large molecules that trigger and immune response
Immune response is directed against "non-self" molecules (usually large & complex foreign molecules)
2 sets of steps for T cell and B cell activities
B cells Activities
T cell Activities
3) Either alone or more often in conjugation w/ helper T cells, the B cells = activated (B cell proliferates , enlarging it's clone)
4) Some of the newly formed B cells differentiate further to become plasma cells
2) B cells Encounter an antigen that fits its antigen receptors
5) Plasma cells synthesize & secrete antibodies whose molecular structure is similar to the activated B cells antigen receptos
1) Antigen bearing agents enter tissue
3) Antigens from the digested antigen bearing agents are displayed on the membrane of the accessory cell
4) Helper T cells = activated when it encounters a displayed antigen that fit it's antigen receptors
2) Accessory cell like macrophage , phagocytizes the antigen bearing agents & the macrophages lysosomes digest the agent
5) Activated helper T cells release cytokines when it encounters a B cell that has previously combines w/ an identical antigen bearing agent
1) Antigen bearing agents enter tissue
6) 5) Cytokines stimulate B cells to proliferate, enlarging its clone
7) Some of the newly formed B cells give rise to cells that differentiate into antibody secreting plasma cells
3 Methods of reacting to antigen
Activation of Complement results in opsonization, chemotaxis , inflammation, agglutination, neautralization, alteration, or lysis of antigen or antigen bearing cells
Inflammation : Simulation of local inflammatory changes in the area, that helps prevent the spread of the pathogens
Direct attack by aggulatination, precipation, or neutrolization of antigens ( make antigen more susceptible to phagocytosis)
Disorders of the immune system
Lines of Defense
Second
Third
First
Ex: Skin & mucous membreanes
Purpose: Stop the entry of bacteria and viruses
Purpose: Fever provides a hostile environment for pathogens that reproduce best under normal human conditions
Purpose: Chemical Barriers kill pathogens with enzymes, acidic environment, & interferons
Ex: Cellular immune & humoral immune response
Purpose: Cellular immune defense against intracellular and extracellular bacteria , Humoral immune response prevent the spread of intracellular infections
Purpose : Natural Killer Cells defend the body against viruses & cancer cells by secreting cytolytic substances called "Perforins"
Ex: Chemical barriers, natural killer cells, inflammation, fever, & phagocytosis
Purpose: Engulfment & digestions or pathogens, foreign particles & debris
Purpose: Inflammation stop spread of pathogens & infection
Autoantic damage body's body's own tissues
Autoimmune disorders may = from viral infection, faulty T cells develop, or reaction to nonself antigen that closely resemble a self antigen
Immune system manufactures antibodies ( autoantibodies) & cytoxic T cells against some of it's own antigen
Artificial vs. Naturally acquired
Artificially :
Naturally
Passive : Involves injection of gamma globulins containing antibodies or antiserum; short term
Active: Occurs through use of vaccines w/ out person becoming ill ; long term
Passive : Occurs as antibodies are passed from mother to fetus; short term
Active : Occurs after exposure to antigen long term
Passive vs Active
Passive: Obtained by recieving antibodies; since there is no antigen contact & no immune response occurs, no memory B cells are produced (short term)
Active: Obtained through antigen exposure; an immune response occurs in the person, on which antibodies & memory cells are produce (Long term)
Innate vs. Adaptive Immune Defenses
Innate
Adaptive
Inflammation (Second line of D)
Respond only against a specific type of pathogens ; respond slowly ( Specific)
Species Resistance (Second line of D)
Accomplished by specialized lymphocytes, which secrete cytokines or antibodies
Resistant to diseases that affect other species
Based on: A) Different chemical environment, B) Body temp. that doesn't provide the conditions required by pathogens, & C) Presence or absence or receptors for particular type of pathogens
Chemical Barriers ( Second line of D)
Mechanical Barriers (second line of D)
Natural Killer (Second line of D)
Guard against many type of pathogens ; respond quickly (Non-Specific)
Includes : Hair, Mucus, & sweat
1st Line of Defense
Function: Prevent entry of certain pathogens by providing a physical separation of pathogens & internal tissues
Examples: Unbroken skin & mucous membranes of the body
Function: Stop spread of pathogens & infections
Characterized by redness, swelling, heat, & pain
Chemicals that kill many pathogens
Acidic Environment : Provided by HCI in gastric juice, lethal to some pathogens
Enzymes : Pepsin in the stomach & lysozyme in tears, (destroy many pathogens)
Interferons: Hormone like peptides secreted by lymphocytes & fibroblasts when viruses or turmor cells are present
Small group of lymphocytes, other than T cells & B cells
Function: Defend the body against viruses & cancer cells by secreting cytolytic substances (perforins) which break apart cell membranes of pathogens (also secrete substances that enhance inflammation)
Phagocytosis (Second line of D)
Are attracted to the injured area
Neutrophils engulf smaller particles
Most active phagocytosis = neutrophils & monocytes
Monocytes attack larger particles
Function: Engulfment & digestions of pathogens, foreign particles, & debris
Fever (Second line of D)
Elevated body temp. causes liver & spleen to take up iron
Phagocytic cells attack w/ greater vigor when the temp. rises
Fever provides a hostile environment for pathogens that reproduce best under normal human conditions
Occurs when body temp. is re-set to a higher set point (results in elevated body temp)
Third line of D
Include Cellular & humoral response
Performed by lymphocytes & macrophages that recognize & remember specific foreign molecules on particular pathogens
Immune Responses
Humoral
Cellular
Some T cells secrete toxins, growth inhibiting factors, or interferon
Types of T cells
T cells also synthesize & secrete cytokines (interleukins & colony stimulating factors) that enhance cellular responses to antigen
Memory T cells provide a quick response to any future exposure to the same antigen by dividing to produce a large number of cytotoxic T cells
Response through cell to cell contact, as activates T cells interact directly w/ antigen bearing cells
Helper T cells: Stimulate B cells to produce antibodies against the displayed antigen
Cytotoxic T cells: Monitor's body's cells, recognizing & eliminating cancer cells & virus infected cells
When helper T cells encounter a B cell that has already encountered & bind to an antigen
Some of the B cells differentiate plasma cells, which produce & secrete antibodies (immunoglobulins)
But most B cells need helper T cells for activation
B cells may become activated & produce a clone of cells when it encounters an antigen that matches it's receptors & binds to it
Antibodies travel through the body fluids to attack & destroy antigens
Other B cells become memory B cells ; these remain dormant at he time, but respond to future encounters w/ the antigen
Cells involved in the immune system
Neutrophils : Help macrophage kill even after it dies
Macrophage : Attack & eat pathogens
Cytoxic T cell: Eliminate bacteria
Monocyte : Attack particles entering the body
Helper T cells : Activate B cells
Natural Killer : Defend body against cancer cells & viruses
Memory B / T cells : Help prevent getting sick from the same pathogen
B cells : Create Antibodies
T cells : Cell mediated immunity
Main Functions
Drains tissue fluids
drains waste products
Fight against infection