Suppressor T cells They are capable of suppressing the function of both cytotoxic and helper T cell They serve functions of preventing the cytotoxic cells from causing excessive immune reactions that may damage the body own tissues, this called immune tolerance Immune Tolerance The condition of not mounting an immune response against the antigens that normally found within one’s own body. Lack of self tolerance underlies autoimmune diseases
Autoimmune Disorders Antigens stimulate development of antibodies that are unable to distinguish antigens of internal cells. Body makes antibodies and T cells against itself and attacks own tissues.
Acquired Immune Deficiency Syndrome (AIDS) Caused by HIV (Human Immunodeficiency Virus) HIV infects T-helper cells AIDS name applied during advanced stages of disease After immune system destroyed, opportunistic infections occur.
LYMPHATIC SYSTEM The lymphatic system take away the excess fluid from around the cells and returns it to the blood The fluid from around the cells is called tissue fluid Once inside the lymphatic system the fluid is called lymph
Functions of lymphatic system 1. To remove excess fluid from the tissue 2. To return the fluid to the blood 3. To produce antibodies and lymphocytes 4. To clean and filter the fluid 5. To transport absorbed fats from the intestines to the blood
Lymph System Lymph originates in blood plasma Interstitial fluid cleans and nourishes body tissues collects cellular debris, bacteria
The main function - collect excess large particles and tissue fluid lymph
Special lymph capillaries --- Lacteals - collect digested fats ( in chylomicrons)
Travel along with blood vessels. lymphatic vessels
Lymphatic System Lymphatic system consist of: Lymphatic tissue Lymphatic vessels lymph
Components of Human Immune System
blind ended vessels
permeable to proteins even cells
Flow of Lymph Once lymph enters a lymphatic vessel, valves prevent lymph from flowing backward (back toward the interstitial space) Lymph can only move toward a collecting duct As it moves through vessels, it is filtered periodically by lymph nodes.
Valves are present to prevent backflow.
Lymph Nodes located in lymph vessels small round or oval structures (filters) depositories for cellular debris bacteria and debris phagocytized
Lymph Nodes inside are masses of tissue which contain WBCs (lymphocytes) invading cells destroyed in nodes and often swell as an indicator of the disease process
Lymph Nodes small organs embedded in connective tissue-– near body surface cluster along lymphatic vessels function – filter lymph as it is transported back to bloodstream mall organs mall organs mall organs embedded in connective tissue embedded in connective tissue embedded in connective tissue cluster along lymphatic vessels cluster along lymphatic vessels cluster along lymphatic vessels function function function – filter lymph – filter lymph – filter lymph • as it is transported back to bloodstream • as it is transported back to bloodstream • as it is transported back to bloodstream
functions of Lymph Nodes 1) filter* – phagocytic macrophages remove & destroy microorganisms enter the lymph from loose connective tissue – prevent them from being delivered to the blood 2) activate the immune system 3) fight against antigens – lymphocytes located in lymphnodes
Include: Function: eliminates abnormal (sick, aged, or cancerous) cells and pathogens Lymph Nodes Spleen Thymus Tonsils
Spleen Largest mass of of lymphatic tissue Upper left diaphragm Has two types of tissue Red pulp-responsible for removing RBC White pulp-site for immune interaction
Spleen functions – Filter blood – defective blood cells and platelets – debris, foreign matter– – site for immune interaction