Body Systems: Circulatory/Immune Systems (The Body’s Lines Of Defense) Flashcards
Immune system: functions:
-Protects against pathogens, bacteria, viruses, worms/parasites, Protozoa.
-Protects against foreign molecules ex) toxins.
-Removed dead or damaged cells.
-Recognize and remove abnormal cells ex) cancers.
The blood (specifically white blood cells) plays an important role in immunity. However the blood does not work alone…
The lymphatic system acts in conjunction with the circulatory system to protect the body against infection.
Lymphatic system and immunity:
-Network of vessels/nodes closely associated with capillaries.
-Vessels collect lymph fluid, which is similar to the composition of blood plasma.
-Lymph helps maintain balance of bodily fluids, bathing cells in interstitial fluid as it mixes with general blood circulation.
Functions of the lymphatic system:
-Found in intestinal villi—> carry some digested fats throughout the body.
-Works with WBC’s to protect body against infection.
•Lymph nodes are where WBC mature.
•Lymph nodes also contain macrophages which trap and destroy bacteria that are circulating within the body.
•When you are sick, sometimes you can feel the swelling of lymph glands behind your jawbone or under your arms.
The body’s three lines of Defense:
1. First line of Defense: physical and chemical barriers:
-Skin.
•protective barrier.
•acidic enough to inhibit growth of microbes.
-lysozymes.
•enzyme produced in tears, saliva, mucous and perspiration.
•destroy cell walls of bacteria.
-HCl.
•stomach acid.
•destroy invading microbes carried in the food.
-cilia.
•found in respiratory tract
•trap microbes and foreign debris.
•cough/sneeze to expel.
Edema:
Swelling.
Permeable:
Leaky.
The body’s three lines of Defense:
2nd line of Defense: non-specific/cell mediated:
-activated if the pathogen gets passed first line of Defense.
-3 types of phagocytes (WBC’s that engulf microbes):
•monocytes move into tissues and become macrophages.
•macrophages phagocytose foreign invaders.
•neutrophils move to infected tissues by a process called chemotaxis.
(chemical signals given off by cells that have been damaged by microbes) and eat the microbe and the damaged WBC.
-Remaining fragments of protein, dead white blood cells, and the digested invaders are called pus.
The body’s three lines of Defense:
2nd line of Defense: inflammatory response:
-Tissue damage due to physical injury initiates a localized inflammatory response:
A non-specific immune response resulting in swelling, redness, heat, pain.
•fever: system wide Defense to more severe damage or infections.
•when neutrophils or macrophages digest invaders, they release chemicals, which go to your brain, and increase your temperature (fever), which kills many invaders.
•a fever makes it difficult for harmful bacteria to survive.
•by taking Tylenol to reduce a fever, you may actually prolong the infection.
Three lines of Defense to help fight infection:
-1st line = non-specific.
•physical surface protection that keep microbes from getting into the body.
-2nd line = non-specific.
•chemicals that comes immediately into play if infectious agent make it past the 1st line.
-3rd line = specific.
•Includes antibodies that must be developed uniquely for each microbe through the action of specialized WBC’s.
Antigens are markers:
-antigens on cell membranes act as markers.
-T-cells distinguish the markers on the body’s cells from those of invading cells.
The body’s lines of Defense:
3rd line of Defense: specific defences/antibody mediated immunity: (0)
-immunity by lymphocytes target pathogens according to the specific markers they present:
1. B-cells: mature in the bone marrow.
2. T-cells: mature in the thymus gland.
3. Antibodies.
The body’s lines of Defense:
3rd line of Defense: specific defences/antibody mediated immunity:
1. T-cells:
-helper T-cells analyze pathogens broken down by phagocytes and recruit B-cells to help identify the foreign particles.
-killer T-cells recognize cells infected by a virus and/or cancerous human cells and destroy them.
-suppressor T-cells monitor T-cells to make sure they do not destroy healthy tissues.
-memory T-cells do not respond on first exposure, but remain in blood for future invasion.
The body’s lines of Defense:
3rd line of Defense: specific defences/antibody mediated immunity:
2. B-cells:
-recruited to the site of phagocytosis by T-cells, where they become activated and divide into 2 different types of B-cells:
•plasma cells.
•memory B-cells.
-plasma cells produce antibodies that recognize and attach to the antigens of specific pathogens, essentially slowing the pathogen down and marking it for destruction by phagocytes.
-antibodies remain in the bloodstream so that next time the pathogen enters the bloodstream, phagocytes can quickly destroy it.
-memory B-cells display antibodies (proteins) that match the antigens (proteins) presented by that particular pathogen.
-remain in the bloodstream so that if they ever encounter that pathogen again, they can quickly call a phagocyte to the scene.
The body’s lines of Defense:
3rd line of Defense: specific defences/antibody mediated immunity:
3. Antibodies:
-antibodies are proteins that recognize the antigens displayed by foreign particles and trigger a series of events to quickly neutralize or destroy them…
-generated after WBC’s destroy pathogens through phagocytosis.
*-binds to the antigen to create the antigen-antibody complex which gets destroyed by macrophages to prevent them from entering cells.
*-Y-shaped proteins made to specifically target invaders.
