THE IMMUNE SYSTEM


_______________ SYSTEM:

Includes lymph, lymphocytes, lymphatic vessels, lymph _______________, _______________, the spleen, and the _______________ gland.

Function:

1. _______________ balance - fluid returns from the tissues to the blood by way of lymphatic vessels.

2. _________ absorption - absorbs fat and other substances through special vessels called lacteals.

3. _______________ - filters microorganisms & other substances from lymph that flows through lymph nodes and in the spleen.

Lymphatic Structure:



Tonsils:



Tonsils contain large amounts of _______________ and provide protection against pathogens entering the body through the nose or mouth.

Lymph Nodes: rounded structures distributed along lymphatic vessels, large groups of nodes located in the _______________, _______________ region, and _______________ region.

Lymph nodes consist of lymphatic tissue containing large numbers of lymphocytes, and lymphatic sinuses containing _______________. Lymph enters the node through _______________ vessels and leaves through _______________ vessels.

As lymph moves through the body microoganisms in the lymph stimulate lymphocytes to divide and spread. Macrophages also remove microorganisms by _______________.

_______________: located in the left superior corner of the abdominal cavity; filters blood, not lymph; contains lymphoid tissue that remove foreign substances, destroys worn out erythrocytes and stimulates division of lymphocytes.

_______________: triangular gland located in the middle of the thoracic cavity, decreasing in size in adults; functions as a site for the production and maturation of lymphocytes. After maturation lymphocytes enter the blood and travel to other lymphatic tissues such as the tonsils and lymph nodes.









IMMUNE SYSTEM CELLS

_______________ - type of white blood cells;

most important of immune cells, estimated 1 trillion lymphocytes in body.

Phagocytes - cells that carry on phagocytosis, the ingestion and digestion of foreign cells or particles; includes two types of white cells , _______________ and _______________, as well as _______________. _______________ is an accumulation of dead neutrophils at the site of infection. Macrophages are monocytes that leave blood, enter tissues, and enlarge approximately 5 X's.

_______________ Cells - release inflammatory chemicals.

_______________ Cells (natural killer cells) - a type of lymphocyte that kills tumor and virus-infected cells using chemical mediators to destroy the cells.





CHEMICAL MEDIATORS:



These chemicals produce several effects:





IMMUNE SYSTEM CELLS

LYMPHOCYTES -

Types: _______________ cells and _______________ cells

Development of _______________ cells - primitive stem cells migrate from marrow to "bursa-equivalent" structure, perhaps the liver

"Bursa-equivalent" comes from the Bursa of Fabricius where B cells were first discovered to develop in chickens.

Development of T Cells - Stem cells from the marrow migrate to the _______________ gland. There are about 5 T cells for every B cell.

There are three main types of T cells:

Stem cells develop into T cells in thymus in months prior to and after birth; T cells migrate to _______________.

T cells develop into _______________ T cells when antigens bind to cell surface.

T cells produce _______________ immunity by directly killing the invading cells with lymphotoxins, by releasing chemicals that attract _______________ to them, chemotactic factor and macrophage activating factor.



B CELLS:



B Cells produce _______________ immunity by circulating antibodies in the blood.



_______________ - called immunoglobulins or gamma globulins

Antibodies have concave combining sites on their surface that "fit" a specific antigen's combining site called an _______________.

Antibodies bind to antigens to form complexes that act in several ways to deactivate the antigens.

1. _______________ toxins

2. _______________ of invading cells

3. _______________ - "prepare for eating" - helps phagocytes attach and digest

4. Initiates the binding of _______________

Summary of Steps in the Immune
Reactions
T-cell & B-cell Activity
1. Antigen-bearing agents enter tissues
2. Accessory cell such as a ____________ eats antigen-bearing agent
3. _______________ are displayed on the accessory cell's membrane
4. _________ __________ is activated by displayed antigen
5. Activated helper T-cell releases ___________ when it encounters a B-cell displaying the antigen
6. Cytokines stimulate B-cell to __________
7. B-cells differentiate into plasma cells and __________ cells
8. Plasma cells secrete antibodies(________________)
9. Antibodies help _______________ antigen-bearing agents

TYPES OF IMMUNITY:





AIDS - ACQUIRED IMMUNE DEFICIENCY SYNDROME

First diagnosed in 1981. Caused by a _______________ (a virus with RNA instead of DNA in its genes) that uses an enzyme to make _______________ from RNA. It integrates its genes into the DNA of T cells. The T cells are destroyed causing a shortage of T cells to fight disease.

Virus was called HTLV-III. Now called HIV, ______________________________.

AIDS disease goes through several stages, with symptoms that may not appear for 5-10 years.

Stage I - _______________ Infection

No symptoms except for possible mono-type symptoms 2 to 5 weeks later. No antibodies can be detected for 8 to 10 weeks.

Stage II - ______________________________

No symptoms but will have antibodies and other abnormal lab findings.

Stage III - _______________ (AIDS Related Complex)

Generalized illness, with or without night sweats, fever, diarrhea, weight loss, fatigue, and rare infections such as oral candidiasis, persistent vaginal candidiasis, and herpes zoster

Stage IV - ______________________________

Deficient immune system not due to known causes such as drugs, cancer, or other diseases; presence of opportunistic infections such as cryptococcal meningitis, ______________________________ pneumonia, _______________ sarcoma, Tuberculosis, Herpes simplex viruses