_______________ 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:

• Lymphatic vessels resemble _______________ and _______________. These vessels collect lymph from the tissues and return it to the blood by emptying into the subclavian veins.
• _______________ organs include the tonsils, lymph nodes, spleen, and thymus gland.

Tonsils:

• _______________ tonsils - usually called "the tonsils", located in the back of the throat
• _______________ tonsil - called adenoids, located near the interior nasal opening
• _______________ tonsil - located on posterior surface of tongue

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:

• _______________ in tears & saliva kill bacteria.
• _______________ - a group of inactive enzymes (at least 14) that become activated by the binding of antigens and antibodies. These enzymes form a doughnut-shaped structure on the cell surface and create holes in the cell membrane causing the cell to die.
• _______________ - a small protein compound that produces immunity from viral infections. Protects other cells by interfering with the ability of the virus to reproduce in neighboring cells. Production of synthetic interferon makes this a promising drug therapy.
• _______________, _______________ & _______________ Activating Factor: attract macrophages and neutrophils to invading organisms.

These chemicals produce several effects:

• _______________ increasing blood flow to the area
• increased vascular _______________, allowing chemical mediators and blood cells to more easily leave the vessels and enter the tissues,
• _______________ ( caused by release of pyrogens )

• Interleukins - stimulate synthesis of several cytokines from other T cells.
  • Interleukin-1 - activates T-cells
  • Interleukin-2 - causes T-cells to multiply

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:

• _______________ T cells - stimulate other steps in the immune process; act as the "on/off" switch.
• _______________ T cells - (cytotoxic T cells) - actively attack cells using lymphokines and lysis of the cells
• _______________ T cells - provide long-lasting immunity

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:

• _______________ cells develop into immature B cells during the few months before and after birth. These are small lymphocytes with antibody molecules in their cytoplasmic membranes. They migrate chiefly to lymph nodes where they form _______________, identical cells.
• Immature B cell develops into an _______________ B cell initiated by contact with _______________ which bind to surface antibodies.
• Activated B cells divide repeatedly forming two groups of cells, plasma cells and memory cells.
• _ _______________ cells secrete 2,000 antibodies into blood per second for several days.
• _ _______________ cells are stored in lymph nodes but will become plasma cells upon a later exposure to the antigen.

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 _______________

TYPES OF IMMUNITY:

• Active natural immunity - results from _______________
• Active artificial immunity - results from _______________
• Passive natural immunity - results from transfer of _______________ from mother to child during pregnancy and breast-feeding
• Passive artificial immunity - results from _______________ antibodies produced in another organism; only temporary

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