Download Lymphatic System and Immunity

Lymphatic System and
Immunity
Fluid Leaves Capillary
Cells
Blood
Blood Capillary
Capillaries
Functions of Lymphatic System
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Drain fluid from around cells
Absorb fat from intestines
Circulate lymph
Filter lymph
Immunity
Right Lymphatic
Duct
Thoracic
Duct
Lymph
• Fluid of the lymphatic system
• Similar to blood plasma and interstitial fluid
Lymphatic Vessels
• Transport lymph
• Lymph is returned to the circulatory system
at either the right or left subclavian veins
Lymph Nodes
• Filter lymph
– Microorganisms
– Cancer cells
• Lymphocytes
• Monocytes
Thymus
• Programs some
lymphocytes to
develop into T-cells
Spleen
• Filters blood
– Worn out RBC
– Bacteria
• Lymphocytes
• Monocytes
Fluid Movement
Edema
• Accumulation of interstitial fluid
Causes of Edema
• Blockage of lymphatic system
• Increased pressure in veins
• Lack of albumin
– Decreases fluid returning to blood capillaries by
osmosis
• Inflammation
Nonspecific Body Defenses
• Skin
• Acid
– Stomach
– Vagina
• Mucus
• Saliva
• Tears
More Nonspecific Defenses
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Phagocytosis
Complement
Fever
Inflammation
Complement
Inflammation
• Bodies response to tissue injury
• Classic signs
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Heat
Redness
Swelling
Pain
Skin
Blood
Tissue Damaged
Histamine Released
Capillary More Permeable
Plasma Leaks Out
Capillary More Permeable
Antibodies Leaks Out
Capillary More Permeable
WBCs Leave by
Diapedesis
Wall of Fibrin Forms
Pus Forms
Steroid Hormones
• Hydrocortisone, cortisone and others
• Depress inflammation
• Used to treat inflammatory diseases
– Rheumatoid arthritis
Antigens
• Molecules often found in the membrane of
cells
• Antigens of foreign cells stimulate an
immune response
Self Antigens
• Antigens of our own cells
• Do not cause an immune response in our
body
– Usually cause an immune response in another
person
• MHC proteins
– Major Histocompatibility Complex
Cells of the Immune System
• APCs
– Antigen-presenting cells
• B cells
– B lymphocytes
• T cells
– T lymphocytes
Antigen-Presenting Cells
• Macrophages
• Engulf foreign cells and attach the cells antigens
on their MHC proteins
Lymphocytes
T Cells
B Cells
B Cell
Foreign
Cell
Receptor
Cytotoxic T Cell = Killer T Cell
Body Cell
Receptor
Helper T Cell
Receptor
Antigen-Presenting Cell
APC
• Macrophages and
other cells
• Engulfs and digests
foreign cells
• Present antigens on
MHC proteins to T
cells
B Cells
• Lymphocytes that
react directly with
antigens
• Require stimulation
from Helper T Cells
• Offspring become
– Plasma cells
– Memory B cells
• Humoral Immunity
Plasma Cells
• Produce huge numbers of antibodies
– 2000/second
Helper T Cell
• Reacts with antigen from APC
• Stimulates Cytotoxic T Cells and B Cells
– Secretes Interleukin II
Cytotoxic T Cells
• Activated by antigens
on any body cell
• Require stimulation
from Helper T Cells
• Destroys body cells
infected with viruses
• Destroys cancer cells
• Cellular Immunity
Memory Cells
• T Cells and B Cells
• Remember antigen
• React to a second invasion of an antigen
more rapidly
Suppressor T Cells
• Stops T cells and B cells after an infection
has been conquered
Cytokines
• Chemicals used in cellular immunity
• Interleukin I
– Produced by macrophages
– Stimulates helper T cells
• Interleukin II
– Produced by helper T cells
• Perforin
– Causes lysis of target cell
Virus
Protein Coat
DNA or RNA
Virus Attaches to Body Cell
Viral DNA Enters Host
Protein Coats Synthesized
Viral DNA Synthesized
Viruses Exit Cell
Host Cell Killed by Virus
Interferon Produced by Dying
Cell
Acquired Immune Deficiency
Syndrome
• HIV Virus
• Attacks and destroys Helper T Cells
– Depresses humoral and cellular immunity
The End