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The Immune System: Lizbet Reyes Period 6 - Coggle Diagram
The Immune System:
Lizbet Reyes Period 6
Innate immunity
vertebrates
barrier defenses
lysozyme in bodily fluids destroy cell walls of pathogens
tears
saliva
mucus secretions
stomach provides an acidic environment kills microbes before pathogens can enter the intestines
purpose of mucos is to trap pathogens or particles
oil and sweat glands on the glands on the skin prevent bacterial growth
cellular defenses
phagocytic cells
Neutrophils, circulate in the blood and are attracted by signals from infected tissues and then engulf and destroy infecting pathogens
Macrophages, large phagocytic cells
natural killer cells circulate through the body and detect through the body and detect an array of surface proteins characteristic of virus infected an cancerous cells
release chemicals that lead to cell death (apoptosis)
inhibits the spread of the virus or cancer
toll-ike receptors (TLRs) bind to the fragments of molecules on pathogens
recognition helps trigger an immune response
TLRs improve the efficiency of phagoctyosis
Many cellular defenses involve the lymphatic system
macrophages are found in the lymph nodes
interferons, proteins that provide innate defense by interfering with viral infections
limit cell-to-cell spread
some white blood cells secrete interferon that activates macrophages
virus infected body cells secrete interferon that causes nearby cells to produce substances that inhibit viral reproduction
inflammatory response
lots of chemicals signals sent out
macrophages and neutrophils discharge signaling molecules call cytokines, some of which promote blood flow to the site histamine triggers the nearby blood vessels to dilate and
defense triggered by physical injury of infection of tissue involing the release of substances that promote swelling, enhance filtration of white blood cells, and aid in tissue repair and destruction of pathogens
mast cells found in connective tissue release histamine
become more permeable increasing redness and local blood supply.
Invertebrates
Immune cells recognize and bid to molecules specific to viruses or microorganisms
Double stranded viral RNA
components of bacterial and fungal cell walls
Hemocytes ingest and break down invaders using phagocytize the epidermal layer
many release antimicrobial peptides that inactivate or kill bacteria or fungi
Lysozyme breaks down bacterial cell walls
Insect exoskeleton provides a physical barrier against infection
Function of the immune system
the immune system is made up of the cells and tissues of the body that interact with and destroy pathogens
they allow the body to avoid or limit infections
molecules don't have to be pathogenic to elicit a response
immune cells release molecules into body fluids that defend the body
animal body is the perfect environmet
nutrients, protection, transport
First line of defense
what happens when foreign subtances get though?
immune system must recognize invaders
immune system needs to distinguish self from nonself
immune cells produce receptor molecules from foreign cells or viruses and activate defense
two types of molecular recognition
innate immunity
adaptive immunity
Prevent pathogens from entering the body, barrier defenses
enzyme called lysozyme is antimicrobial and breaks down bacterial cells walls
mucus
tears
saliva
Secretions that trap or kill microbes also provide a defense
digestive tract
airway
skin or shell
entry by pathogens is blocked but not impossble
Adaptive immunity
humoral immune response
the activation and clonal selection of plasma and memory B cells, which produce antibodies that circulate in blood and lymph
clonal selections, B cells form clones in response to a specific antigen to amplify the response the cells can have
one clone forms a plasma cell that produces anitbodies to fight the anitgen
One clone forms a mermory cell that is long lasting and has receptors for the antigen
Primary immune response
body is first exposed to a foreign antigen and a B cell is activated, producing plasma cells that make antibodies against
activation begins when an antigen to amplify the reponse the cells can have
enhance by cytokines, small proteins that regulate the function of other cells
Secondary immune response
happens when the same antigen invades the body at another time; faster and greater magnitude
Cellmediated immune respond
Activation involves T cell receptors involves activation and clonal selection binding to antigens displayed by of cytotoxic T cells (Tc), which identify antigen-presenting cells (APCs) and destroy infected cells.
Pathogen enters host cell, Snzymes inside cell cleave the foregin molecules into smaller peptides that can be combines with host proteins and moved to the cell surface
T cell bind to and lyse infected cells and cancer cells
Characteristics
lymphocytes form from bone marrow and circulate through the blood and lymph recognizing specific pathogens
T cells, mature in the thymus
B cells, mature in the bone marrow
any substance that elicits a Bor T cell response is called an antigen
recognition occurs when an antigen binds to a B or T cell receptor
vertebrates only
Pathogen specific recognition
Active & Passive immunity
Active, happens when being exposed to an antigen leaves circulation memory cells
result of an infection
result of vaccinations
passive, happens when an individual receives antibodies
Placenta to fetus
Breast milk to infant
Disruptions in immune function
Autoimmune disease
immune system turns against specific molecules of the body allowing cytotoxic T cells to attack healthy cells belonging to self
Lupus, rheumatoid arthritis, type 1 diabetes, MS
immune system avoidance
changes in epitope experssion allows an antigen to avoid the immune system or the antigen goes into and inactive state
HIV escapes the immune system and attacks ( infects helper T cells)
Allergies
antibodies produces after first exposure to an allergen attach to receptors on mast cells
the next time, the allergen enters the body, it bonds to mast cell molecules and releases histamine and other mediators