Lecture 16
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Transcript of Lecture 16
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 ToleranceThe 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
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
fluidlymph
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
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 lymph nodes
Include:
Function:
eliminates abnormal (sick, aged, or cancerous) cells and pathogens
Lymph NodesSpleenThymusTonsils
Lymphoid tissues
Spleen
Largest mass of of lymphatic tissue Upper left diaphragm Has two types of
tissueRed pulp-responsible
for removing RBCWhite pulp-site for
immune interaction
Spleen functions – Filter blood – defective blood cells and platelets – debris, foreign matter– – site for immune interaction