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