Exercise 38 The Lymphatic System and Immune Response.

Exercise 38

The Lymphatic System and Immune Response

Lymphatic System

Lymphatic vessels Lymphatic tissues

Tonsils Primary lymphatic organs

Thymus and Bone marrow Secondary lymphatic organs

Lymph nodes, spleen

Lymphatic System

Lymphatic System

LymphFluid lost from the capillariesEdema

Functions of the lymphatic system:Transport lymph to the blood vesselsProtects the body

Lymphatic vessels

Lymphatic capillaries Lymphatic collecting vessels Lymphatic trunk Right lymphatic duct - drains lymph

from:Head right upper extremityRight thoraxDrains into right subclavian vein

Lymphatic vessels

Thoracic duct – drains lymph from:Rest of the bodyDrains into left subclavian vein

Cisterna chyli Characteristic of the lymphatic vessels

Walls with 3 tunicsPresence of valvesPresence of abundant anastomoses

Lymphatic vessels

Primary lymphoid organs

Bone marrowContain the stem cell that will give

rise to all lymphocytesSite of B cell differentiation or

immunocompetency Thymus

Site of T cell differentiation or immunocompetency

Thymus

Secondary lymphatic organs

Lymph nodesBean-shaped NumerousRegional lymph nodes:

• Cervical• Axillary• Inguinal, etc

HilusAfferent and efferent vessels

Secondary lymphatic organs

MicroscopyCapsule and subcapsular sinusTrabeculaCortex

• Outer cortex (follicles)• Germinal center containing

dividing B cells• Deep cortex or paracortical area

• Contain T cells

Secondary lymphatic organs

Medulla• Medullary cords• Medullary sinuses• Contain macrophages and plasma

cells

Secondary lymphatic organs

SpleenCapsuleWhite pulp

• Central artery• Lymphocytes

Red pulp• Venous sinuses• Reticular tissue• Macrophages arranged I splenic

cords

Spleen

Lymphoid tissues

TonsilsOne pharingeal Two palatinesTwo lingualsPresence of germinal centerPresence of crypts

Tonsils

The immune response It is a systemic response Destroys or neutralizes foreign substances Characteristics of immune responses

Memory• Immunocompetent lymphocytes are

monospecificSpecificityAbility to differentiate self from nonself

The immune response

AntigensForeign proteinsPolysaccharidesHaptens

Lymphocytes Responsible for the immune

response Autoimmunity

Organ, cells and cell interaction of the immune response

Hemocytoblasts in the bone marrow give rise to lymphocytes

Types of Lymphocytes:B - will stay in the bone marrow for

maturation (immunocompetence)T - will migrate to thymus for

maturation (immunocompetence)Natural Killers

Organ, cells and cell interaction of the immune response

B and T cell will then leave bone marrow and thymus, enter the blood stream and travel to secondary lymphatic organs Site for clonal selection

Organ, cells and cell interaction of the immune response

B and T cell will bind to specific antigens and then undergo clonal multiplication

B cell may becomeMemoryPlasma cellHumoral immunity

Organ, cells and cell interaction of the immune response

T cell may becomeMemoryCytotoxicHelperSuppressorCellular immunity

Antibodies and tests for their presence

Characteristics of antibodies or Immunoglobulins (Igs)Produced only by plasma cellsThey are plasma proteins

(gamaglobulins)Found in all body secretions

Antibodies and tests for their presence

Classes of antibodiesIgM, IgG, IgA, IgD, IgE

Structure of the immunoglobulins2 heavy chains2 light chains

Antibody