Lypm Immunity System

8/10/2019 Lypm Immunity System

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LYMPHATIC SYSTEM

AND IMMUNITY


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Lymphatic System and ImmunityMajor function in the body

Circulates body fluids and defends againstdisease-causing agentsInnate defenses and immunity protect against

general and specific damage or diseaseLymphatic system is closely related tocardiovascular and digestive systems


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Lymphatic system - is composed of lymph vessels, lymph nodes,and organs.

The functions of this system include theabsorbtion of excess fluid and its return to the blood stream,absorption of fat (in the villi of the small intestine) and the immune system function.

Immunity - is the body's capability to repel foreign substances andcells.

The immune response includes both specific and nonspecificcomponents.The nonspecific responses are the first line of defense.

- Nonspecific responses block the entry and spread of disease-causing agents. Highly specific responses are the second line of defense and aretailored to an individual threat.

- Antibody-mediated and cell-mediated responses are twotypes of specific response.


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Lymph organs

bone marrow lymph nodes spleen thymus

The immune system isassociated withdefense against disease-causing agents,problems in transplantsand blood transfusions, and diseases resulting fromover-reaction (autoimmune,allergies) and under-reaction (AIDS ).


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Bone marrow - contains tissue that produceslymphocytes. B-lymphocytes (B-cells) mature in thebone marrow. T-lymphocytes (T-cells) mature in thethymus gland. Other blood cells such as monocytes and

leukocytes are produced in the bone marrow.

Lymph nodes - are areas of concentratedlymphocytes and macrophages along the lymphaticveins.

Lymph Organs


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Lymph Organs

Thymus secretes a hormone, thymosin , thatcauses pre-T-cells to mature (in the thymus)into T-cells.

Spleen is similar to the lymph node exceptthat it is larger and filled with blood. Spleenserves as a reservoir for blood, and filters orpurifies the blood and lymph fluid that flowsthrough it. If the spleen is damaged orremoved, the individual is more susceptible to

infections.


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Lymph Nodes

Along lymphaticvessels and scatteredthroughout the bodyGroups near surface

regions of:Cervical area AxillaryInguinal

Capsule withtrabeculaeInner network ofreticular fibers and

fibroblasts


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LYMPH NODES


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Spleen

Largest mass of lymphatic tissuePassage for splenic artery, splenic vein andefferent lymphatic vesselsWhite pulp

Lymphocytes and macrophagesCentral arteries

Red pulp

Venous sinusesSplenic cords

RBCs, macrophages, lymphocytes, plasma cells, andgranulocytes


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Functions of Spleen

Macrophage removal of damaged bloodcells and platelets

Storage of platelets

Hemopoiesis of fetus


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ThymusTwo lobes separated by capsule of connective tissue

Trabeculae - separate lobes of tyhmus into lobules

Cortex - produce thymic hormonesTypes of cells in cortex

T cells, dendritic, and macrophagesEpithelial cells

Medulla localization and storage of mature thymic cellsT cells matureThymic (Hassalls) corpuscles

Populates secondary lymphatic organs and tissues with T cells


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Nonspecific Resistance (Responses)

Present at birth - tears and saliva secrete enzymes thatbreakdown bacterial cell wallsImmediate protection against variety of pathogens andforeign substances

First line of defenseSkin and mucous membranes - lining the respiratory,digestive,urinary, and reproductive tracts

Physical and chemical - Damaged cells releasechemical signalssuch as histamine that increase capillary blood flow

into the affected area (causing the areas to become

heated and reddened).


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Nonspecific Resistance (Responses)

Second line of defense Antimicrobial proteins, natural killer cells andphagocytes, inflammation, and fever

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Specific Resistance or Immunity(Responses)

Defense against a particular type of invader Antigens (Ags) - antibodies specific to a given antigen(molecules carried or produced by microorganisms thatinitiate antibody production)

Foreign and provoke response

Specificity for particular foreign bodiesSelf from non-selfMemory for previously encountered Ags

Provokes more rapid and vigorous response

Immune system

has a memory component that improves response time when aninvader of the same type (or species) is again encountered.


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isorders associated with thelymphatic system

Lymphomas - progressive painless enlargement of lymph nodesthroughout the body


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Lymphodenitis - caused by microbes transported in lymphfrom other areas of infection. nodes become inflamed, enlargedand congested with blood, and chemotaxis attracts largenumbers of phagocytes.

ex. septicaemia or bacteraemia - Septicaemia (blood poisoning) is causedwhen bacteria enter the bloodstream and multiplyuncontrollably.

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